Shims for packing up cutting tools

[Robert MullanParticipant @robertmullan69263]

It is necessary to pack up cutting tools in the lathe to get the point to the centre of the lathe spindle. As a beginner where can I get a selection of shims without paying a fortune for metal I don’t need?

I am using a Cowells 90ME. 

[Robert MullanParticipant @robertmullan69263]

[Colin ReedParticipant @colinreed51485]

Shimming lathe tools to centre hight definately made a difference for me. For my Taig lathe I’ve managed to get away with using old feeler gauge leaves and bits of cut up coke can.

Edited By Colin Reed on 19/05/2009 12:20:47

[Jim WhetrenParticipant @jimwhetren72358]

Not long after I got my Cowells 90ME, I abandoned the shimming process as too tedious.

I made a duplicate of the suppplied single tool post and bored it to 16mm and slit along the bore. It was also tapped for a height adjusting screw.

A pinch bolt was used to clamp the tool post to a 16mm x 22mm long sleeve fastened to the tool post stud on the top slide.

With a tool fitted, the tip was set to centre height with the screw, then the pinch bolt tightened; taking a matter of seconds.

[billy lairdParticipant @billylaird83330]

Hi all i use hack saw blade’s and old tape messure’s to “fine tune” just cut to suit your tool post  regards billy

[electronicParticipant @electronic]

Hi!
 I use offcuts of glass fibre used in the manufacture of printed circuit boards – for all my coarse packing. Regards electronic.

[John Wood1Participant @johnwood1]

Hi Robert

 

As you can see from the above replies shims can take many forms. Basically, anything of the right thickness and not too soft would do. You can buy sheets of shim steel and brass which you can cut into strips as required but the fun is in finding other materials for free!  I have a few bits of steel packing case banding, some bits of plastic which can be (say) from drinks bottles, food containers etc., similarly metal from drinks cans and the like, I have even pressed bits of an old CD into service before now.

 

Of course it is well worth investing in a good quality quick-change tool post with several toolholders, such holders can be fitted with your most used tools, adjusted to dead centre and locked ready for instant use whenever you need them. Believe me the investment is really worthwhile if you are a regular lathe user with limited time.

 

All the best

John

[Geoff TheasbyParticipant @geofftheasby]

I, too, use an old feeler gauge, plus cut up aluminium beer cans, which are about 3 thou.

 

I plan to use unetched double sided printed circuit board (from Maplin’s, about 62 thou) and unembossed portions of used credit cards (about 32 thou)

 

Regards

Geoff

[Clive FosterParticipant @clivefoster55965]

RS Components (http://uk.rs-online.com/web/) sell plastic shim stock in individual sizes and assorted sheet packs.  Cuts with scissors.  Colour coded for thickness which is great for sorting out when you get them mixed up.  For example stock no 681-407 is 8 sheets about 6 x 12 inches listed at £12.45 but plus VAT and plus delivery but if you spend more than £25 delivery is free.

Clive 

[Brian JohnParticipant @brianjohn93961]

Why don't all tool posts come with height adjustment ?

[JasonBModerator @jasonb]

Cost, rigidity, etc

[herbert punterParticipant @herbertpunter99795]

I use transformer laminations for height adjustment (when I'm not using the QCTP).

They come in various thicknesses depending on the size of the transformer.

Bert

[Paul LousickParticipant @paullousick59116]

For thin packers I use pieces of "Band-it" strap. Metal straps about 0.6 – 0.8mm thick. Used for wrapping around large industrial size packages. Usually thrown in the bin at warehouses.

[John McNamaraParticipant @johnmcnamara74883]

Hi All

Being a veteran bin scrounger from way back I keep my eye out for steel banding as used on bales and packing crates, It comes in 1/2" 5/8" 3/4" and 1' approx. widths. You often find it on building sites, the perfect material for this job and free!

I keep a supply of cut to the correct length with the ends cleaned up pieces near the lathe, for fine adjustment a small quantity of thinner pieces made from tinplate in a matching size makes the job easy,

I keep often used tools together with their own set of packers that give the correct height.

A little height setting tool I made up in a hurry one day and have been using ever since makes height setting a doddle. Just a small magnet with a post attached that sits on a flat on the saddle.

My lathe has a 4 way tool post I don't find it difficult packing the tool. Most of the time you only need two or 3 tools set to complete a job.

Regards
john

Edited By John McNamara on 30/07/2014 08:49:45

[Les Jones 1Participant @lesjones1]

Hi Brian,
If you make a tangential tool holder to fit your tool post you can make fine adjustments to the height by moving the tool bit up or down. I find that I use the tangential tool holder most of the time.

Les.

[Neil WyattModerator @neilwyatt]

I have a wall mounted bin with 'shimpack' written on it. Anything small flat and potentially useful as a shim, gets thrown in it with other bits *(like the outside of old ball races) useful as packing when clamping etc.

My most used 'shims' are a battered bit of aluminium the right thickness for 5/16" square shanked tools in my square toolholder and the short pressed steel 'spanner' from a pop riveter, which suits my favourite boring bar.

Neil

[mechman48Participant @mechman48]

I have used al of the above at one time or another; then moved on to a QCTP, much easier, I now use my tangential holder 90% of the time, with QCTP holders set for specified task such as chamfering, parting off, Knurling (diamond & straight), DTI set up, & a couple of boring bars.

George

[Howard LewisParticipant @howardlewis46836]

Noting the comments about tangential tool holders, I have made some. The first was to a design published some time ago, in one of the M.E. magazines, to use 1/8 toolbits, and included the design of a sharpening jig.

Note the Imperial units!

Last week, I made four "beefed up" versions, to use 5/16 toolbits.. One for myself, and the others for The WaterWorks Museum in Hereford. To fit their Colchester and the Loughborough lathes, the 3/4 deep holders need about 3/16 milled off the bottom, when I got there.

Having already made Tool Centre Height Gauges, it was then just a matter of bringing the tip up a little to contact the underside of the blade on the gauge.

The results surprised me greatly. The finish, using a 0.0025/rev feed on a 0.050 cut did not differ to much from that of a 0.001 cut. So much so, that the tangential tool is still in use on the lathe, in place of a holder for CCMT0604 tips!

The 5/16 toolbits ( Kennedy 5% Cobalt) had been ground on a Worden cutter grinder, to the same 20 degree angle as the sharpening jig. (As usual, one job created others, since a holder for the toolbit had to made to to locate it in the Worden).

Howard

[MikeParticipant @mike89748]

Cans from different breweries vary in wall thickness by the odd thou or two. It would be a valuable service to all model engineers everywhere if there was a handy chart of brands and thicknesses which I am prepared to produce after a suitable period of research. Just send full cans to Mike at…………………………..

[Howard LewisParticipant @howardlewis46836]

For anyone keen to make a Tangential Tool holder, (as opposed to buying one of the Australian made ones on sale in U.K.), the article which led me to make one, firstly for 1/8 toolbits, and more recently for 5/16 toolbits, was on page 12 of Model Engineers Workshop No 156 – Autumn 2009.

The only complicated part was making the slot at 12 degrees across the face which was already at 12 degrees to the side of the toolholder shank. The article suggested making the sharpening jig from hardwood, and using woodscrews to clamp. I made mine from metal, and used 4BA capscrews to clamp the bit in the jig for sharpening.

Howard

[TomfileryParticipant @tomfilery]

Robert,

I have a Cowells 90 and made a QCTP for it (dovetail cut out on the fixed part and mating "key" on the holder. Worked great and made life so much easier! I cut the dovetail block on my Axminster micro mill (which only just managed to do it!) and ended up cutting the mating "keys" from aluminium. Given the small cuts you are forced to make using the Cowells, rigidity wasn't an issue.

Were I doing it again (I won't as I bought a Myford and now rarely use the Cowells) I'd make the holders which have a simple large hole bored in them and which clamp onto a central large circular vertical pin. Once you get a production line going you soon turn them out (pun intended).

Regards Tom

[thomas oliver 2Participant @thomasoliver2]

I have a compartment box in which to keep shim. I measure and mark all the strips with their thickness, When shimming a tool I stick the shim to the bottom of the tool with double sided sticky tape. On my Boxford, I made tool holders for small 3/16th square HSS bits with the tool slot at a small upward angle. The tool was fixed with short Allen grubscrews, set to centre height, then clamped in the normal way. Both methods allow instant tool clamping. LIke John Macnamara, I find that a four way tool post and HSS tools perfectly adequate for all of my work which includes model diesel engines, steam engines and locos, vintage motor-cycles and so on. It must be realised by beginers to modelling that most model parts require sharp shoulders to allow close fitting. TC tools have slightly rounded noses and I find them useless for most of my work and much prefer HSS which is easy to grind. I use TC tools for Cast Iron and tough steels when necessary.. Why go to the bother of buying expensive tangential tooling or having the tedium of making them in profusion when the old 4-way does the job adequately. Can a normal lathe tool be ground to the same angles and produce the same results as a tangential tool? I have not tried. Maybe someone has and can enlarge on it.

[Jon GibbsParticipant @jongibbs59756]

I like the idea of the double-sided tape but cheap feeler gauges and odd bits of flat stock for thicker shims are my parts of choice.

**LINK**

At £2.60 a pop and guaranteed burr-free flatness it seems a steal to me – HTH.

My biggest problem with my 4-way is that every side is a different height!

Have taken the plunge to a Dickson QCTP though. Can't wait to try it out.

Jon

[frank brownParticipant @frankbrown22225]

I too have a shim box (or two), the problem is that 16 SWG shim is too thick and the next i can find is .8 MM, or a variation of the above. I seem to spend too much time shuffling through the boxes, micing up bits (writing the value on them) and only to come to some conclusion like I'll change the .25" block for a 4mm and start again.

Soon I shall make a selection of shims based on some thing I can mill, taking as an example, gauge block sets, So I shall get a piece of 1/8" /3mm steel cut a couple of shims of the end, then mill off .005" all over and then cut two more shims, then cut another .005" off and repeat, so I'll have a series of gauges based on 0, -5, -10, -15, -20, -25, -30 thou. So that's seven milling operations, a posher way is to have a 1, 2, 4, 8, 16, 32 progression, that would give a 0 -> 63 range with seven shots on the milling machine and a stack height of 0 to eight times the thickness of the material used. I'll have to check and see what the typical shim size is.

The height of the cutting edge must never be above the centre line, else the front edge of the tool is rubbing not cutting, however having the tool too low just reduces the amount of top rake. So this is directly scaled from the diameter of the work. So I reckon TAN 1 degree is .0174, that means if you are turning a bar of 2" diam, if your tool is .017" below centre,its effective top rake is reduced by one degree. OK for Ali (starts off at six degrees), bad for brass tool starts of at zero degree. Like wise extremely poor for turning .01 diam watch spindles

Frank

Edited By frank brown on 01/08/2014 19:44:27

[John DurrantParticipant @johndurrant47282]

I have spent most of my working life shimming tools in a four way tool post. I am now retired and will spend the next few days making Howard Halls QTP for my hobby lathe. I will then have a shim bin.

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