Useful Workshop Hints & Tips.

The content of this page is for information only.

By Ken Webber

1.

Vice jaws.

Ever thought of replacing those hardened, serrated standard vice jaws with mild steel, aluminium or brass ones? The standard ones are often a pain in the neck in many respects. Although they will grip rough surfaces securely they will mark finished surfaces, take teeth off files and saw blades and require the use of awkward vice clams to protect delicate finishes.

Alternative jaws can be made of almost any size material provided that it is equal to or bigger than the originals. Fixing holes can be transferred from the original jaws and it is a good idea at this stage to replace the usual slotted countersunk screws with socket head cap screws. These are much easier to remove and replace when changing jaws in the future. You may well have to dismantle the vice and use an impact screwdriver to get the originals out. Equally it may be found that they are loose anyway. Other advantages may be found as follows:

1. They can be made of any shape to aid forming and bending

2. Large area jaws may be made for holding sheet metal more easily.

3. Grooves may be machined in them for holding bar sections.

4. They are easily refaced as a pair in the four jaw chuck, on a milling machine or on a shaper or surface grinder.

5. Being of soft material they may be used as filing or sawing guides.

6. The tops may be drilled to take standard pins or to hold sheet metal horizontally, or tapered components.

Think about it. The effort and time involved in making them will be worthwhile for the convenience offered. Milling, drilling and shaper vices can benefit from the same treatment.

Gripping stuff!

2.

Reaming.

However careful we are with initial centre drilling in the lathe a drilled hole rarely runs true with a turned diameter produced at the same setting. This is particularly true if we have to rely on off-hand grinding of our drills. Such drills rarely cut to size anyway. Reaming the hole after drilling to size doesn't always help, as we all know that a reamer will always follow a pre-drilled hole.

The solution to this is to centre and drill the hole say 1/32" undersize to start with. Then bore the mouth of the hole to just take the business end of the 'reaming size' drill to a depth equal to the drill diameter. Follow through with the reaming drill and finally ream. Such a procedure will make holes run true and also compensate for drill grinding inaccuracies.

Boring stuff?

3.

Fine feeds.

Do you sometimes feel you could do with a finer radial feed than the small diameter cross slide index will allow? If so try this.

Turn the top slide (compound slide) clockwise to an angle of 11.5 degrees relative to the lathe centreline. (Possibly showing 78.5 on the graduated scale). Then using the saddle to turn the diameter and the top slide to put on the cut you will find that an indicated .005" on the top slide dial will advance the tool radially .001".

Talking of feeds, it is sometimes difficult to maintain a consistent rate of feed on long lengths using the saddle handwheel.

Try this....

Disengage the leadscrew from its gear train at the headstock end, engage the saddle nuts and rotate the lead screw to give the required feed. Myford supply a handwheel for the tailstock end of the leadscrew but it is not difficult to devise a simple hand crank if you lack the kosher item.

If you have a small lathe which has no rack and pinion drive for the saddle, ignore the last paragraph.

Feed for thought?

4.

Lubrication.

1. When tapping blind holes, try filling the hole with a paste type tapping compound before inserting the tap. As the tap progresses down the hole the chips produced will be forced up the flutes by the tapping compound trying to get out. This gives less chance for the tap to get wedged in the hole thereby risking a tap breakage.

2. Make your chuck jaws resist wear and stay true longer by cleaning thoroughly with something like WD 40 and then sprinkle a small amount of powdered graphite on the scroll and jaw teeth whenever you change them. (Graphite is obtainable from locksmiths and good ironmongers in small squeeze packs).

3. When applying an oil gun to lubricating nipples the back pressure developed often results in oil overflowing and making a mess when the gun is removed. Try putting a clean rag over the nipple before applying the gun. This will... a) provide a better seal between gun and nipple, ... b) filter the oil as it goes in and... c) avoid a mess as you withdraw the gun.

Slip this one in!

5.

File cleaning.

One of the worst enemies of files is what is known as the 'File Card'. The spring steel tines are hard and tend to blunt the file teeth, and their diameter will not allow them to get between the teeth of anything finer than bastard cut teeth. A brass wire suede brush applied parallel to the teeth will do a much better and safer job, but even this will not cope with smooth cut file teeth. The solution is a tooth scraper.

Take a piece of copper tube about 5/16" diameter and flatten one end for a length of about 3/8" by squeezing in the vice. File the squeezed end square with a smooth file leaving any filing burrs in place. Apply the tool at 45° to the file surface with the edge 90° to the slope of the teeth and gently push. You will be surprised at the amount of muck it will shift. When worn simply re-file the end of the scraper.

File this for later?

6.

Wire brushes.

Ever wished that you had a small wire brush for cleaning seams for soldering, removing flux in comers, old paint from joints or for giving the smoke box a really good clean? Well you can, with very little time and effort.

Two things are needed:

1. A short end of soft metal tubing about 3/16" or 1/4" diameter, annealed brass, copper, steel or aluminium say 4" to 6" long. 2. About three feet of braided or twisted brass or steel wire. Picture hanging wire or small diameter bowden cable is ideal.

Soft solder the wire to stop it unravelling and cut a nice clean end. File the end smooth. Don't be tempted to grind it! If the coil gets caught up in the grinder it will have your fingers off like a cheese cutter.

Now thread the prepared end in one end of the tube and out the other, leave a small loop and go back the other way, loop and feed back again and continue until the tube is as full as you can get it. Cut off the spare end (doesn't matter now if it frays) and squeeze both ends of the tube flat in the vice for about 1/4" to grip the wire tight. With a light touch, grind back the loops to about 1/8" from the flattened end of the tube. Wear safety glasses, (they are easier to replace than a MK1 eyeball) as sometimes little bits of wire may fly. Bingo! Little wire brush.

Obviously different sizes can be made and the brush can be bent to get into awkward comers. When the business end gets unusable, grind the wire back to the tube (remember your safety glasses), flatten the tube end a bit more and cut about 1/8' off the end of the tube to expose more wire.

Get scratching.

7.

Vertical slide setting.

Setting the vertical slide at right angles or parallel to the lathe spindle axis can be a time consuming business with square or dial test indicator. There is however a much quicker method.

Mount the face plate on the spindle nose having ensured that the threads, register diameter and abutment face are quite clean. Mount the vertical slide loosely on the cross slide and adjust the saddle and cross slide so that the vertical slide can be pressed firmly against the face plate in the required position. While holding the slide thus, tighten the securing bolts.

For mounting parallel to the spindle axis, secure a parallel mandrel in the chuck. (A short length of silver steel will do.) Mount the vertical slide as above and push against the mandrel. Secure as before.

Vices can be aligned using similar principles except that parallels may be needed in the vice jaws to enable us to 'reach' the face plate or mandrel. No parallels or mandrels? Don't worry. Remember that silver steel is parallel, round and very close to nominal size and that bright drawn mild steel sections are as parallel as you will need. They are also surprisingly square and very near to nominal size.

Square up to it!

8.

Datum finding.

Many machining operations require the 'picking up' of an edge or face. Let's look at two basic, simple and practical methods of doing this

1. Touching the edge with the cutter.

In this case contact is usually sensed by sight or sound but invariably results in an unknown amount being taken off the work. A coating of blue or black felt tip pen. or cigarette paper stuck on with a thin film of oil, helps this common method. Once contact is made. move over half the diameter of the cutter and hence its centreline will be aligned with the edge. Naturally this method cannot be used if it is imperative that the datum face is not to be damaged or marked in any way.

2. Using a mandrel and feelers.

This avoids damaging the reference face but requires a small amount of extra effort. The cutter is replaced with a suitable diameter mandrel or piece of silver steel. The work is advanced to the mandrel until say a .010" feeler strip is just gripped. Any piece of thin shimstock would do. Repeat this two or three times, noting the slide index each time. Remove the feeler and move the slide the thickness of the feeler plus half the diameter of the mandrel. Hence the datum edge is now under the centre of the spindle. This method can, with care, position the spindle to the work within plus or minus 0.001" easily.

Those of you with wigglers. wobblers, centre finders, optical chucks, jig borers and computer numerical control machines please disregard the above.

Get the edge!

9.

Uses for pipe cleaners & fag papers.

Pipe cleaners and 'roll your own' cigarette papers are most useful items to have in the workshop.

Use pipe cleaners for:

Cleaning small holes, tubes and dies.

Applying small dabs of paint and varnish.

Applying adhesives, grease, oil, fluxes and jointing compounds.

Wiping off excess solder while molten.

Tying rubbish sacks.

Keeping bandsaw blades, wire etc. coiled.

Keeping nuts and washers together.

Keeping paint brush bristles straight while drying.

Use Ciggy papers (0.0015 thick) for:

Packing for correcting squareness or parallelism in set ups.

Protecting finished surfaces. (Stick on with grease).

Picking up surfaces with milling cutters, (Stick to surface with smear of grease, advance cutter until paper is just removed, the cutter is then a nominal 0.001 in. from surface.

Using taper mandrels that are just that much too small.

As very sensitive feelers.

Picking up turned surfaces. (Advance tool with paper between tool and work until paper just tears when pulled away.)

Cleanup, touchup and pickup?

Nearly forgot! You can also use them for cleaning your pipe and rolling your own.

10.

Polishing sticks.

As most will know, these are wooden sticks covered with emery paper and are used in the instrument and watchmaking business for polishing and removing that last 'tenth' from a diameter. They are quite expensive and don't last long particularly if a sharp edge or corner is inadvertently caught. However, they can be easily and cheaply made in whatever shape, form or length you may require.

Use Ramin strip or section from a DIY store and the abrasive material of your choice. Glass paper, wet or dry, emery cloth, leather, aluminium oxide, silicon carbide, felt or whatever. Lay the abrasive face down and cut to width using a steel rule and a Stanley knife. ( Watch your fingers). Press double sided tape (ideally the sort used for carpets but the thinner stuff will do) onto the wooden stick and press down well. Strip the paper coating, position the abrasive carefully and press down firmly. I find that a wall paper seam roller does well for this.

Any section of suitable timber can be used, including dowelling. In this latter case, measure the diameter of the dowel, multiply by 3.142 and cut the abrasive to the resultant dimension. If the abrasive is a bit stiff bind over tightly with string or elastic bands and leave overnight. The felt or leather strip is ideal for polishing using lapping paste as the abrasive.

Give it some stick.

11.

Lathe bed wipers.

Why is it when lathe manufacturers go to the trouble of fitting a bed wiper to the headstock side of the saddle do they not fit one to the front of the tailstock?

If we turn hard brass or cast iron, swarf tends to spray all over the place and builds up in front of the tailstock. Move the tailstock and inadvertently lift the front slightly and the swarf gets underneath. Re-clamp and the result is bed marking which is undesirable if not unsightly. Hence to me, a bed wiper attached to the front of the tailstock is a good idea. You don't think so ? Then read no more.

Next problem is what to make this wiper from. Ideally an adaptation of the one on the saddle and why not? Thick piece of felt, simple cover strip and two 4BA round head screws. Easy. Get lost I hear you cry. I'm not taking my headstock apart. It turns parallel as it is and it took four hours to get it to do so. Try this on the Myford.

Remove the tailstock and remove the large nut and plate that you will find on the underside. At the front and rear you will find a socket head grub screw. Fill the head of one of these with putty, Plasticine, Bluetack or grease and slacken the other one, one or two turns. Now undo the socket head grub screw under the tailstock handwheel and the base will come off. Now is your chance to see how the clamp works, give it a clean and a touch of graphite grease.

Now do what is necessary on the base i.e. two appropriate tapped holes, in the correct end please. Clean the mating surfaces, give a very thin smear of grease and reassemble in the reverse order of disassembly. Provided that you don't touch or move the screw whose head you have filled it is most unlikely that the tailstock setting will have been affected.

The alternatives will be less permanent and will probably involve an adhesive of some suitable type to stick a felt or flexible rubber (oil resistant) strip to the appropriate place in question. Draught excluder comes to mind and I used part of an old plastic one that I found in a builders skip. It's now falling off simply because I did not take the trouble to clean the surfaces enough before using the double sided tape. I've now acquired a piece of draught proofing brush strip which seems to offer the ideal solution. Must get down to tapping the tailstock base!

Autoslydenwypen

12.

Drill chucks.

Key type Jacobs and similar chucks seldom give any trouble unless they become clogged with swarf, brick and plaster dust (when drilling overhead) or if they are not lubricated occasionally. To lubricate, apply one or two drops of light oil or WD40 at each end of the outer sleeve and the chuck body. You'll be surprised at the difference that this will make if the chuck is a bit stiff.

Dismantling can seem a bit of a mystery until you know how and then it's quite simple. First of all it is important that during the operation the chuck jaws must be adjusted to be underflush with the chuck body as no force must be applied to them when pressing the chuck apart.

We now require two steel sleeves made from odd pieces of tube of diameter dependant on the size of chuck in question and of a length say 1/4" longer than the chuck. Bore one piece of tube so that it will bear on the outer sleeve but clear the chuck body at the rear end. Bore the other end so that it will bear on the teeth at the front end but clear the chuck body (where the key holes are). Make sure that the tubes are square at each end.

Use the first tube to press off the outer sleeve over the chuck nose. It can take quite a bit of effort if the chuck is old and has never been apart. Use a vice to do the pressing but if not a hide or plastic mallet will suffice. Once the sleeve is off, the action and reassembly will become obvious. Note which jaws go in which holes in the body and clean everything thoroughly. Lubricate very sparingly with oil or grease (I prefer powdered graphite) and reassemble using the second tube.

Spares for Jacobs chucks should be available by order from any reputable dealer as are the keys.

Thats the drill!

13.

Tool sharpening.

Double sided oil stones are quite expensive items and intended for sharpening of flat bladed tools such as plane irons and wood chisels, engineers scrapers, gouges, knives, flat topped form tools and the like. However with use (and abuse) they tend to become worn in the centre part, become clogged with dried oil and loaded with steel particles. In this state they are of little use to man nor beast and are often discarded, found in junk shops or even turn up at club auctions for very nominal sums.

They can however, be readily refurbished with a small amount of effort. You will need:-

1. A lump of hard paving stone, a piece of plate glass or a piece of boiler plate,

2. A lump of Plasticine and

3. A tin of coarse silicone carbide lapping paste. Build a wall of Plasticine around the edge of the plate, mix some of the lapping paste into a slurry with a little paraffin and tip It on the plate. Put the oilstone on top and rub with a circular motion covering the area available as evenly as possible. Lift the stone occasionally to redistribute the paste and continue until the stone is flat. Don't expect instant results and you may need to change or add more abrasive when it stops 'biting'.

Stone me! It works.

14.

Gripping rough surfaces.

The first job on a rough casting is often to create a datum surface from which dimensions may be taken or upon which geometry may be based. However, we are often faced with the problem of gripping rough surfaces which are often none too parallel in smooth jawed vices or chucks.

Trying to do this will often result in a poor grip, damage to vice jaws and sometime disastrous movement of the job when machining starts. Naturally we are going to knock off as many obvious knobs from the casting first but then try putting a piece of thin plywood, hardboard or thick cardboard between the job and the jaws. Several thicknesses of kitchen paper will also work.

This will of course crush with the force of clamping but this is the idea to take up any unevenness and to distribute the clamping force over a larger area than would otherwise be. The idea can also be applied to the clamping of work on the machine table, on the faceplate and in chucks.

More gripping stuff!

15.

Radial holes.

One of the most difficult and time consuming jobs that crop up is drilling radial holes in small pins and shafts to take solid or split pins, particularly small ones. For instance a half inch split pin at one inch to the foot scale is only .041" diameter and to put a hole of this size centrally through a shaft that is only 3/32" diameter is almost impossible using conventional marking out techniques and a vee block.

Try this, take a piece of say 1 " square mild steel about 1.5" long and mark out with a centre line on two adjacent faces. On these centre lines, carefully and as accurately as possible, mark centre and drill two holes - one to take the component to be drilled on one of the centre lines and on the other the size of hole to be drilled for the pin. If the hole to be drilled is to be dimensioned from a shoulder then the drill guide hole can be sited that distance from the end of the block. Put the component to be drilled in the hole, put the drill down the other and, if your marking out is anywhere near, then the job is done.\par A stop can easily be arranged for siting holes a particular distance from the end of a shaft. The method is worthwhile for even a one off job and the time and effort involved is worth it in terms of scrapped parts, broken drills and bad language. The method can be used for radial holes at 90 degrees using square stock or holes at 60 degrees using hexagonal material.

Don't get cross (or bored).

16.

Anti chatter.

Countersinks will often chatter, particularly those with an even number of equally spaced teeth. This little problem can be readily solved by folding a small piece of rag, say 1" square, twice to give four thicknesses of material. Put the rag between the hole and the countersink, use a slow speed, say 400 rpm and bingo no chatter.

Make sure that the rag pad is SMALL and that there are no loose ends or straggly cottons or fibres sticking out. Keep your fingers out of the way!

If buying a new countersink go for a single flute type. They rarely chatter and are easy to sharpen.

No talking??

17.

Improvised 'Tee' handles.

Tee handled hexagon wrenches (posh allen keys) are most useful items but are expensive to buy. In any case they are generally of standard lengths, the handles are quite bulky and cannot be removed. So, if you want one, try this.

Take an old, worn or broken hexagon wrench of the size that you require, (junk shop, junk box. Club auction, boot sale or odd spare one) and cut off about a 1 " length. This is easier said than done but if you nick it all round on the corner of a grinding wheel, put it in the vice with the nick in line with the top of the jaws and, most important this, cover the end with a thick wodge of rag and clout it, it will snap off.

Then:

Measure the hexagon across corners and across flats. Subtract the across flats dimension from the across corners dimension. Divide by 2.

Add this dimension to the across flats dimension and select a drill to this size or near enough.

Now make a tee handle of the length you require. (I've got one that reaches the moving jaw securing bolts on my milling vice. It's about a foot long), in one end drill an axial hole using the drill you have selected, about 1/2" deep. The other end can be cross drilled for a tommy bar or made into any other type of handle that you prefer. In the very small sizes a knurl may be enough.

Drive or preferably press the hexagon wrench piece into the axial hole after grinding a chamfer on the cut end. I've found that this drive fit is sufficient to retain it but if you want a belt and braces job, put a drop of Loctite retainer (601) in the hole first.

Socket and see!

18.

Using parallels.

Machine vices in general usually need a packing strip or parallel under the workpiece to support it to ensure parallelism or squareness depending on the operation. The problem is that in the case of a drilled through hole or a through slot the parallel gets in the way and in the case of a hardened parallel is quite a disaster for the cutter. This problem is usually overcome by using two thin parallels on edge so that the drill or slot drill will pass between them. However, such thin parallels or strips often fall over or become misaligned when loading or removing the part or while tapping the part down tight to overcome ‘jaw lift’ which is inherent in most vices.

The problem can be overcome by putting a short, square ended compression spring or piece of sponge rubber between the two parallel strips so that they are held against the fixed and moving jaws respectively. Problem solved.

Incidentally, I find that a small lead mallet or a posh shot filled plastic faced (Thor), neither of which bounce, is more effective than a hammer to get the component to grip the parallels. If neither comes to hand put a block of hard wood between the hammer and the job.

Even more gripping stuff!

19.

Universal Tee slot tenons

The tee slots on your mill or cross slide are parallel or square to the motion of the slide by design and manufacture, and hence are used to locate standard items such as vices on the table or slide. Other items such as angle plates may need such a reference.

One way of ‘picking up’ a tee slot is to machine a bar of material to be a close slide fit in the tee slot to effectively duplicate the tenons in the base of a standard vice. This of course limits them to use on the one machine. A ‘universal tenon’ is more versatile and easy enough to make.

Measure the total depth of the tee slot and add 1/4" . Measure the width of the tee slot and divide by 2. Choose a piece of bright mild steel to these dimensions and about 4 to 6” long. Tap two through holes in the centre of the plate width and about 1 “ from each end to suit a couple of set screws. (Bolts threaded to head). 2BA, 3/16”, 1/4” or even 4mm will do . Cut these screws to a length just less than the tee slot width. Assemble the set screws into the tapped holes, against the side of the tee slot and there you have it. Vary the dimensions to suit your application as necessary.

What a line up!

20.

Tee nuts & studs.

Tee nuts and studs are essential items for clamping purposes on all machines equipped with tee slots. They can be bought as standard sets but are expensive and never seem to be the right length. Tee bolts with integral heads always seem to be a particular curse to me. However, sets to suit your particular machine can be readily, inexpensively and quite easily made.

STUDS

Use standard screwed rod which is readily available in 1m (or even 36") lengths in DIY stores from 1/4"-1/2" or 6-12mm depending on your age (?). Cut to length (2 of each in a range to suit yourself say in 1/2" increments), turn and chamfer each end and ideally put a screwdriver slot in each end to hold them if you happen to get a stiff nut or to secure them on the table by tightening down in the tee nut. Nuts and washers are readily available from the same source. While about it you may like to go the whole hog and make some stud extenders which are simply short pieces of hexagon material tapped to enable two studs to be secured together. This reduces the range of studs to be made.

TEE NUTS

When I was an apprentice, the use of bolts with filed heads, heads beaten wider with a big hammer on an anvil and bolts with heads with a pin through them were common place for milling machine setups. Why we never had standard studs and tee nuts I shall never know.

If you have a milling machine, then tee nuts are no big deal. Mill in a stick, mark out, drill and tap, cut to length, remove sharp corners and there you have it, or them. If you have no milling machine then there are two possibilities. Turn or fabricate. Turned ones are ideal in the small sizes as are needed for machines such as Myford. Choose a diameter of mild steel about 1/4" or 3/8" bigger than the bottom of the tee slot is wide. Turn a shoulder about 1/16" less than the top part of the tee slot is deep and about 1/64" less in diameter than the top of the tee slot is wide. Drill and tap to suit your studding. Part off to leave a flange about 1/16" thinner than the bottom of the tee slot is deep. Remove sharp edges before you part off. Now file two opposite sides of the flange equally until the nut slides easily in the slot. Wasn't difficult was It?

Fabricated ones are almost as easy. Select a strip of mild steel of a section that will be an easy fit in the lower part of the tee slot. Drill a series of suitably spaced holes in the strip about a 1/16" larger than the O/D of the stud to be used. Take some nuts of appropriate size, mount on a short piece of studding in the lathe and turn a shoulder 1/16" long and of a diameter to locate in the holes in the strip. At the same setting turn away the hexagon to a diameter to suit the upper part of the tee slot.

Cut the strip into pieces midway between the holes and silver solder in position. Clean up, deburr and you have tee nuts.

What a load of rubbish I hear you cry. However, this method does avoid the need for tapping and dieing and involves only turning, drilling and silver soldering. The joint should be strong enough for practical purposes.

Nutty suggestion?

21.

Gaskets.

Fluid and gas tight joints often need gaskets, and some of these may be complex in shape, (such as cylinder head gaskets).

Materials may range from brown paper to 1/32" commercial gasket material. Simple round washers can be cut with hollow punches made to fit one inside the other to ensure concentricity. More complex ones may be cut as follows.

Hold or stick with a thin film of grease a suitable piece of gasket material against the shaped face and gently tap around the periphery with a small copper, brass or aluminium mallet. (a 6" length of 1/2" diameter material will do.) Continue tapping until the material is severed. Holes can be cut by placing the ball end of a ball pein hammer over the hole and gently tapping the other face. If fragile this latter can be used to just mark the hole position and the cut finished with a hollow punch, sometimes called a wad punch.

Copyright. Tappit, Cuttit and Sealitt Ltd.

22.

Heat treatment.

Small components such as flat springs, small pivot pins, punches and taps are not easy to heat treat by conventional methods. How do you hold them if, for instance, the whole item is to be hardened and tempered? Larger parts of silver steel or gauge plate are heated to 'cherry' red (whatever that may be) and quenched. They are then polished bright and tempered by the colour method, (light straw to blue), dependent upon the application. Small parts are difficult to hold, awkward to polish and difficult to see with respect to the tempering colours. Two alternatives may help us out of the problem.

The plate system.

Take a small piece of say 1/16" thick mild steel of suitable size and, for round parts, put a small set in it to stop the parts rolling off. Hold with tongs or old pliers and place the small part to be heat treated on the top. Heat from the underside with propane or whatever until the plate, and of course the component, is of a suitable hardening temperature. Then simply tip the part from the plate into the quenching media. For tempering, use the same method. Polish the top of the plate clean and bright with emery, lay the part on top, (no need to clean it up) having dried it first and very gently heat the plate from the underside watching for the appropriate tempering colour to appear on the plate. Again tip the component from the plate into the quench pot and the job is done.

The tube system.

This is often considered better for small cylindrical parts. Take a piece of suitable diameter steel tube in which the part is a loose fit. Clean up the outside of the tube and follow the general idea outlined above. This method gives more even heating, avoids having to hold the parts, reduces cooling between heating and quenching and makes the tempering colours much easier to see.

A hot tip?

23.

File adaption.

There are many occasions when something other than a straight file would be of use in awkward corners and angles. Such files are commercially available and are known as RIFFLERS. These are quite splendid but are expensive particularly if we only have occasional use for them. However common files of all sections can readily be bent to suit the job in hand.

Heat the area of the file to be bent to a full red heat and bend as needed against a block of wood, manipulating to shape with a wooden stick if needed. Don't use metal or the file will be cooled and the teeth blunted. When suitably shaped, reheat to red for hardening and quench in oil to avoid glass hardness and possible cracks. It is not necessary to temper.

Remember that files are essentially high carbon steel and old files make very good scrapers, woodturning tools, small chisels and form tools. Anneal, remove teeth, shape as necessary and reharden and temper to suit the application.

File for reference?

24.

Hollow punches.

Hollow punches are most useful items for cutting holes in non metallic sheet materials. They are commercially available from usual suppliers and most of us will have seen hole punch pliers with a rotating head that caters for different sizes. Most of the commercial items are tapered on the outside for ease of manufacture and sharpening. This is of little consequence if punching holes for belt buckles but for model making we could do with something that will give a bit more precision and cater for odd sizes. Such punches can be easily and quickly made from silver steel, or even mild steel for one off use on soft materials.

There are two basic types. Those that are bevelled on the inside and those that are bevelled on the outside. The former will cut quite accurate holes and the latter are more suitable for outside diameters.

So, decide if you want to cut an accurate outside or inside diameter. For example I'll choose an inside.

Take a piece of silver steel of appropriate diameter and about 2" long. If not available, the next size up and turn it down for say 1/2" to the diameter required. Drill axially about 3/8" deep to leave a wall thickness of about 3/32". Now turn the compound slide to an angle of 15° and very carefully with light cuts bore the mouth of the hole until a razor edge is left.

In the case of a punch to cut an accurate outside diameter, the bore needs to be the diameter required and hence the outside diameter needs to be about 3/16" or so bigger. Turn the outside diameter to a razor edge as before. When cutting concentric washers adjust the dimensions so that the ID punch will slide in the bore of the OD punch.

These punches can be hardened and tempered to dark brown for repeated usage but for the odd one off job, perform quite well if simply left soft. I used a simple mild steel one for cutting twenty five 1 " diameter washers from roofing felt without any problems.

A close grained block of wood such as beech should be used when using such punches. In small sizes, say under 1/4" diameter for 'inside' punches, a countersink may be used to form the inside taper.

See you around!

25.

Paint preservation.

Do you get irritated as I do when paint in a tin develops a skin when the level is about one-third the way down the tin? This is due to the amount of trapped air reaching a critical volume so that the oxygen content will oxidise the paint surface and so produce the skin. (I think). The cure must be to stop the air getting to the fresh paint surface. There have been several methods advocated in the past such as pouring a thin layer of water on the surface before putting the lid on and there was once, I believe a commercial invention that created a vacuum in the tin to produce the desired effect. Try this dodge I have used for many years.

Scrounge some greaseproof paper from the cake making activities of the other half and cut a disk the outside diameter of the paint tin lid. Insert this disc into the tin so that it rests on the paint surface and there you are. (It helps to fold the disc loosely in half when inserting.) The paint will keep skin free regardless of how long it is kept even without the lid on!

When you need the paint again, cut round the disc, throw it away, stir the paint and away you go. There is only one small problem. Mark the tin 'DO NOT TILT' or one day you may invert the tin or enthusiastically shake the tin to mix the paint and it's messy to fish the saturated disc out of the tin. I know, I've done it.

Paint in general comes in standard tins of 250ml, 500ml and 11 other sizes. It is useful to cut several discs of each size and keep in stock for future use. The lower the paint in the tin the more useful is the dodge. It works down to the last few mm.

Keep your lid on!

26.

Centre punching.

For many years now I have not visually lined up a centre punch to mark the intersection of two scribed lines on a piece of work. If you give the operation some thought it will be realised that a scribed line is in fact a groove in the work surface and can be felt with a fingernail or a scriber traversed at right angles to the line. So, the line can be felt with a sharp centre punch. Once located, the punch can be slid along the groove until it is felt to meet the other one. Ensure verticality and give the end a light tap. With a bit of practice this method gives 90% or better reliability, which improves with practice and for me, is quicker and better than the visual method. Obviously it also helps when, with advancing years, eyesight is not what we might wish it to be and saves the use of magnifying devices.

Incidentally, as with all centre punching, make the first strike a light one. It's much easier to correct if needed.

Feeling better?

27.

Marking out.

Need to do some accurate marking out? No height gauge? Needs to be better than oddlegs, scriber and a rule? If you have a vertical mill then accurate marking out becomes a doddle.

Put a turned, hardened and centred centre punch in the spindle nose and use the co-ordinate motions of the table to position the job under it. Then a sharp light movement of the quill will suitably indent the work as a centre punch would. If the punch be replaced with a spring loaded item then lines may be scribed. If holes need to be spaced around a circle with no dividing apparatus available then this can be done using co-ordinates to position the holes. Zeus charts or a bit of trigonometry will be needed here.

While not as convenient, the use of a vertical slide on the lathe will do a similar job. If certain (or confident) a centre drill may be used instead of the centre punch.

Do remember to take out any backlash in the leadscrews when using such methods.

Spot on.

28.

Tool centre height.

We all know the importance of tool centre height in turning operations. How do you check it when setting up a tool? Take a trial cut? Use a gauge of some sort? Then try this old dodge.

Grip lightly a thin 6" rule or similar bit of material between the tool tip and the OD of the cylindrical workpiece. Sight the strip from the tailstock end of the lathe and if the rule is vertical the tool is on centre. If you don't think your judgement is good enough then stand a try square on the cross slide and sight the rule against the blade.

Try it. It works

29.

Reference squares.

Want to generate a true reference with which to check your try square after you next drop it? Then try this.

Select a piece of mild steel about 2" diameter and, say, 6" long. Actual sizes are not critical. Grip in the chuck and, using a fixed steady, face and center the end. While thus set up recess the faced end about 1/32" deep to leave approximately a 1/8" wide rim on the end face. Reverse in the chuck and with a similar set up to that above, face and center the other end and turn down to say 1" diameter by about 1" long. Knurl this diameter or turn some shallow grooves to form a handle and give a grip. Now set up between centers with the carrier on the suitably protected 'handle' end and turn to clean up. Check as accurately as you can for parallelism. Adjust the tailstock as necessary until the o.d. is as parallel as you can get it coupled with as good a finish as possible. When satisfied, take a light finishing cut across the end rim. Remove sharp corners and there is your cylindrical square. Use it for reference only, don't let it go rusty and look after it carefully. You'll be glad you made it.

While making it you will also have made the tailstock central. Bet you have been meaning to do this for ages!

Square up to it.

30.

Tool setting on centre.

We realise that for a lathe tool to work efficiently it must be on the centreline of the workpiece. If the tool is set too low then we will be left with a 'pip' when parting off or facing, the front clearance will be increased and the back rake angle will be reduced. With a tool too high it will not or at the best have difficulty cutting due to decreased front clearance and increased back rake and as it approaches the centre it simply will not cut but rub on the front clearance face.

The method of adjusting the tool height is dependant on the type of toolpost fitted to the machine of which more later but how do we know that the tool is suitably on centre when initially setting up. There are several alternatives plus some that I have never heard of and some that I have forgotten while using my search and stab method of typing. Tell me and remind me respectively.

Trial and Error.

Probably the most commonly used method. A tool is set up as near as possible by eye to centre and a light cut is taken either on the workpiece or on a scrap piece of material.

Depending on the result the tool is raised or lowered by whatever means is available and another trial cut taken. this is then repeated until a satisfactory result is obtained.

Tool Setting Gauge.

This is not a standard accessory but can be readily made. I remember seeing one made from an old trysquare that had seen better days. Such a gauge may have a base to sit on the lathe bed or the top of the cross slide and have a 'beak' at work centre height (like a height gauge) to establish tool tip height.

Previously turned or parted short end.

Such a piece of material will indicate the centre and can be used to set the tool height by eye.

Using a Morse taper centre.

A suitable dead centre (or a live one for that matter) may be mounted in the headstock, or the tailstock as is most convenient, and used to set a new tool to centre height again by eye.

The double scribe.

This is useful for 4 jaw or faceplate work where only a plain surface is presented. It's also useful for setting boring tools on centre. Set up the tool nominally and with the spindle stopped, scribe a line with the tool tip using the cross slide to traverse.

Then rotate the spindle as near as possible 180 degrees and scribe another line. The tool is then above or below centre by half the distance between the lines.

'D' bit.

Even a D bit can help out. Remember that a D bit is ground away to its axis. Hold it in the chuck with the flat face downwards and set the turning tool to just touch this flat face.

The Steel rule method.

This is the method that I use as a rule. (groan). Again the tool is set up as near to centre height by eye and a small steel rule is lightly gripped between the tool tip and the work or a short end of round material. The rule is then sighted from the tailstock end of the machine and should, if the tool is on centre, be vertical. If the top of the rule is sloping toward the front of the machine then the tool is too low and vicky verky as tis said. If you are not too good at judging such alignments put a trysquare on the lathe bed and sight the rule in comparison.

Tool Height Adjustment.

In general there are 5 common types of toolpost supplied as standard items by different lathe manufacturers.

1. The plain clamp type such as the double bar or the three leg plate, the latter often having a spherical washer and seating under the clamp nut.

2. The plain four square toolpost indexable in most cases in 45 degree increments.

3. The American or 'boat' type with a slotted post, spherical seating and a curved boat tool seating.

4. Quickchange toolposts such as the Dickson or Myford. I think that they are the same or very similar.

5. The solid column type. Often used as a rear toolpost for parting tools, the tools being mounted upside down. Some of these may have a boat, a pair of serrated folding wedges or two adjustable screws opposite the clamp screws.

3,4 and 5 above have their own built in tool height adjustment, the boat type achieving this by 'rocking the boat' so to speak but of course this then in turn affects the rake and clearance angles which may or not be critical dependant on the work involved. 4 has the advantage of fine screw adjustment and once set the entire toolholder complete with tool can be removed and replaced with an alternative tool similarly set. However such a system is not an inexpensive item.

1 and 2 (2 being the most common on small lathes such as Myford) generally require some form of 'packing' to bring the tool to a suitable height. This is generally achieved by using odd scraps of sheet or strip material of all sorts of odd sizes to suit. Metal banding strip or trimmings from the shop guillotine being not uncommon. Selection of such packing is commonly very much on a trial and error basis and I've seen some nasty cuts from ends of such packing being left protruding from the toolpost.

However it is possible with only 6 pieces of packing to achieve tool height adjustment from 0.004" to 0.247" in 0.004"increments or with 7 pieces (add a 0.002") from 0.002" to 0.249" in 0.002" increments. This is more than sufficient for the type of work generally performed. Yes, I know that it is difficult to believe at first glance but it's true.

Consider the 6 pieces.

Piece 1. is 0.004"

Piece 2. is 0.008"

Piece 3. is 0.016"

Piece 4. is 0.032"

Piece 5. is 0.064"

Piece 6. is 0.125"

(for 4,5 and 6 read 1/32, 1/16 and 1/8 respectively) Having said that it doesn't take a genius or a degree in mathematical statistical numerology to get the idea.

0.004 = 1

0.008 = 2

0.012 = 1+2

0.016 = 3

0.020 = 1+3

0.024 = 3+2

0.028 = 1+2+3

0.032 = 4

0.036 = 4+1

0.040 = 4+2

0.044 = 4+1+2

0.048 = 4+3

0.052 = 4+3+1

0.056 = 4+3+2

0.060 = 4+3+2+1

0.064 = 5

0.068 = 5+1

0.072 = 5+2

0.076 = 5+2+1

0.080 = 5+3

0.084 = 5+3+1

0.088 = 5+3+2

0.092=?

0.096=?

That will do. Now you have got the idea. Do the rest yourself. Make a couple of sets or more to suit your tools.

Old feeler gauges for the smaller thicknesses available from club auctions at reasonable prices.

Are you setting comfortably?

Kens Quickies

Useful one-liners.

1. What has the greater worth? Your eyesight or a pair of safety glasses.

2. You don't use files without handles, do you?

3. Do you switch off the power when you change chucks, drills or milling cutters? If not, why not?

4. Did you know that the tripod bush hole on all cameras is tapped 1/4 Whitworth?

5.WD 40 works out at about 1/4 the price if it is bought by the gallon instead of aerosols. Use a cheap garden sprayer to apply it.

6. 1 cup vinegar, 1 tsp salt and 1 tsp citric acid powder makes a splendid cleaner for brass. Rub on or soak, rinse in very hot water, shake off excess and allow to dry.

7. To get press fits to start, try taper reaming the mouth of the hole until the shaft just enters.

8. Don't throw old tooth brushes away. They are ideal for cleaning taps, spindle nose threads, chuck jaw threads, keyways and teeth as in gears.

9. A clean shoe brush is ideal for polishing complex copper and brass ornaments. It gets the metal polish out of the crevices.

10. A recorder cleaning brush or a domestic sink drain brush is ideal for cleaning out morse taper sockets.

11. Joints made with Loctite can be released by heating to about 200 degrees Centigrade.

12. File "safe edges" are not safe. Run an oil stone along the edge to remove the swell caused by the tooth cutting process.

13. WD 40 is excellent for lubricating and cleaning oil stones.

14. Woodscrews drive much more easily if they are lubricated by dipping the point in tallow before insertion.

15. A brass suede shoe brush makes an excellent file cleaning brush.

16. Plain nuts can be made into "stiff nuts" by cutting a radial slot with a hacksaw to half the thread diameter and closing the cut by squeezing in the vice.

17. Don't waste cereal boxes. Chop them up into pieces of suitable size and use them in the workshop for calculations, notes, memos, sketches, protecting finished surfaces in the vice, under clamps, protecting machine tables from the effects of clamping and getting a better grip on cast surfaces.

18. WD 40 removes the residue of sticky labels.

19. A triangle of sides 3:4:5 will give a right angle opposite the 5 unit side.

20. Lolly sticks and wooden toothpicks are useful for applying glue, small dabs of paint, small amounts of grease, soft and silver solder flux, solder paint, jointing compound.

21. Counterbores produce much better holes in thin materials than do twist drills. Use taper reamers for opening up such holes.

22. Emery cloth interposed between chuck jaws and work will give a much better grip especially on cast surfaces.

23. When press fitting steel into aluminium apply a film of grease to avoid siezure.

24. Avoid press or drive fits that can't be pressed, pulled or driven out. One day you'll regret it.

25. Do you use self adhesive sanding discs and have a job getting them off the backing plate? Try this. Spray liberally with WD 40 and leave for an hour or so. They then peel of quite easily. Remove any adhesive residue with a rag and WD40.

26. Decorating? Using sheet glaspaper? Abrasive paper bought on the roll is more economic if more expensive in the first place. It lasts far longer and cuts much better.

27. Decorating? Need to put the brush down for lunch? Wrap the business end in clingfilm and it will stay soft until you need it again.

28. What is the most useful gear wheel in a set? Answer. The 60T. With a little ingenuity it enables you to divide 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60. What other gear wheel of reasonable size will do this?

29. When finished with Loctite clean the end of the nozzle before fitting the cap. Loctite hardens in the absence of air and this simple tip will prevent Loctite hardening in the depths of the cap and eventually blocking the nozzle.

30. No parallels? Need a size that you don't possess? Buy or acquire a 12" length of your size choice of bright drawn mild steel. Cut it in half, remove burrs and bingo, a pair of parallels. Such material is surprisingly square and adequately accurate enough for general use.