Quick change tool post and ball cutting

Hello, Margaret,

There is quite a bit of stuff online about ball-cutting. I made a ball-cutter similar to the one shown in this link, and found it simple to make and works well.

LINK

Its item 13 in the list of gadgets. The page on Lathe Modifications also has some stuff on QCTPs - maybe some of the other ideas may be useful to you as well.

Mikes strategy of keeping tools and shim sets together in a divided box is undoubtably effective but takes a, to me, terrifying degree of super organisation.

No way could I mange that so pre-loaded posts were the way for me.

One advantage of of pre-loaded posts over swopping tool and shim sets in a single post is that tool projection distance settings are retained. Just as with a QC system. So if you have to make several parts needing tool changes during a job swopping posts rather than tools means you don't necessarily have to reset the dials after each change. Probably best to verify before the final cut on a precision part tho'.

Clive

This is the way I want to go, Clive, with my 8x16 [M10 toolpost stud] lathe. The only snag is finding someone who actually sells standalone 4 way toolposts. QCTPs, by contrast, can be found everywhere.

If anyone knows a source, please let me know.

Have considere QCTPs but stuck with my 4 way.

Cost Would cost over £250 for the nuber of holders needed fo the tools used.

Space Having a small, congested workshop, akin to Rubik's Cube, little or no space to store the unused holders.

Rigidity Wary of being less rigid that a 4 way toolpost becaus of the overhang and the interfaces.

All of which reduce rigidity.

But, you makes your choice and pays your monery.

Do what best suits you.

A 4 way toolpost will carry 3 tools. Shims? old feeler gauges, or cut up biscuit tims (About 0.010" thick in most cases. Pity that so many food tins are corrugated, although maybe the lids could be cut up and reused.

My lathe has 2 longitudinal T slots in the Cross Slide , so I made an indexable 4 way toolpost to go on the rear. This carries the parting tool, and tools for front and back chamfering.,

There may be a picture in my albums, showing front and rear in position.

Just checked, third from bottom. If you want more details, PM me, and I'll try to find the number of the Issue with the article.

MEW published an article on it (One of the few times that I made drawings, rather than a sketch on the back od an envelope )

You can change the dimensions to suit your machine., if you so wish.

HTH

Howard

Edited By Howard Lewis on 24/07/2023 14:01:49

Ball and Radius cutting.

Any device which allows a tool to be rotated about the axis of the lathe can be used for ball or radius turning.

Arc Euro sell such attachments for the lathes that they sell.

You could even make one yourself. Might be an interesting and informative exercise.

And money saving for a tool that is likely to be unused for a lot of the time.

Having been left a small legacy, I bought a Repton Radius Turner, from Chronos. It will cut up to 60 mm, and given my limited useage, am satisfied with it.

Howard

They are not hard to make, I did one while still at school for my Unimat3. Even if you don't have a mill the six sides of the block can be done in the 4-jaw along with the central hole. Slot can be done with block on the topslide packed up as needed. Make a triangular Lomass one while you are at it to get tailstock ctr clearance when needed

Yes, I'm just rather short on time and material.

Bill

Chester still list a hobby lathe size one but the price is insane. More than a bottom end QC I think. Quality doesn't look any better than the one I bought years ago at a relatively less insane price when QC stuff was still expensive.

I wasn't overly impressed by it.

Less than well made in general although the slots were well finished and parallel to the base. I found the centre square too small to make holding 4 tools practical. The indexing plunger didn't locate accurately enough to be really useful. It all worked, but not as well as I'd hoped given the cost.

Shop soiled Myford size ones can be found on E-Bay for £25 right now which might be worth a look. No screws.

I ended up making my own from standard sections which worked well.

Clive

In that case RDG, Chester, Chronos, E-bay all sell 4-way posts, just look at the sizes and see what may fit unless you are also short of cash

Thanks all. Great information as always and plenty for me to digest!

Best wishes

Margaret

Hello Margaret,

When I bought my first 'real' lathe - a Myford ML 10 - it was only fitted with a clamp and nut for holding any tool. Shimming various tooling became a nightmare of not only working out the total thickness of shims for any specific tool but a real struggle keeping together lots of pieces of shims with each tool

I bought a short length of mild steel bar 1/2 x 1 1/2 (12 x 38) and cut it into short pieces about 2" long. I milled a groove in these using the lathe, holding each piece by the tool clamp using a shim to get the position the right height.

With the parts slotted they were then cross drilled for 2 BA grub screws and each fitted with a 1/4 x 1/4 HSS tool blank. The tools were ground by hand and shimmed in the holders to give a poor mans quick change independent tooling which did me proud until I updated to an ML7 (and then later still a Super 7) when I bought a Myford Dickson QCTP. I have never regretted that purchase and apart from a boring bar holder and knurling tool something I still use to this day for all turning including parting off.

Hope that's of further thought

Best - Tug

Edited By Ramon Wilson on 24/07/2023 18:33:22

I have the wedge tyoe from Arc and very pleased with it.

I am curious as to why most wedge or button qctp have the tool holders at 90 deg and not 180  ie opposite each other?

Edited By petro1head on 24/07/2023 18:55:36

Edited By petro1head on 24/07/2023 18:58:35

That is so you can have say a right hand tool which has it's shank across the lathe axis and then change to say a boring bar that has it's shank along the axis without having to move the post.

Larger posts tend to have three or four sides that can take tools so you get the best of both worlds.

Edited By JasonB on 24/07/2023 19:14:59

3 sides, never seen a wedge one with 3 sides

Edited By petro1head on 24/07/2023 19:21:48

Well, I've got to disagree with the 4-way enthusiasts here.

I think a QCTP transforms using a lathe. Yes, the holders a fairly expensive, but you don't have to buy loads at once, you don't have to fool around with shims, just a simple screw height adjustment to set each tool up, you can take a toolholder out, noting the setting on your dials, put in another one and use that, then swap back to the original and know that the dial setting is still good (yes, I know that a 4-way should index properly, but on a cheap lathe it probably won't, and the indexing mechanism only works with the toolpost and topslide aligned - no setting the topslide round to clear the tailstock)

Also, it takes up less room than one of those four way abominations with its tools sprouting out in inconvenient directions ready to take a chunk out of your hand when you're trying to mic the workpiece (and you can hardly ever use all four positions with a sensible combination of tools).

I have one of these:

https://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Lathe-Accessories/Tool-Posts/Model-000-Quick-Change-Tool-Post-Set

It would have probably been better to have the next size up, but I re-used it from another lathe and I don't have any problems with the rigidity of it - parting off diameter is only limited by the lack of low speed torque of the brush motor on my lathe, and the maximum depth (15mm) of the carbide insert toolholder I usually use - I have gone considerably deeper in stainless steel with a blade type holder, but I worry about cooking the motor with such antics. Of course you have to have the holder set accurately to centre height, but that's easy with a Quick Change toolholder...

Wedge type. Fiddling with shims with oily fingers in a chip-filled four-way is the devil's idea of a joke.

Over the years, I have purchased several parting tools and holders but only one has been satisfactory. It was a holder with it's own double wedge clamp on the usual type of taper sided HSS blade, from RDG Tools. All the others were naff for various reasons and will shortly be disposed of. Set up by running saddle close to (stationary) chuck, slack QCTP bolt, swivel to make parting blade lay flat against chuck face and clamp the post. Tool now square with lathe axis and work. Very quick setting up. VFD speed set to about half turning speed for the metal being worked on. Newton Tesla VFD motor seems to have plenty of power for parting off. Wonderful combination of tools and drive system on my S7. No chatter, parts off very easily with a frying bacon sound. Only intermittent cuts done at too fast speed, seems to make the qc tool vibrate up and down. Necessary to keep speed down. I usually use thicker tools with a brazed on carbide tip under the Myford clamp. Thicker shank tools stiffer and also need less packing. If it's a nuisance, how about super gluing the packing together in one solid lump? Mainly used for cast iron machining.

I'm with Andy, in that I consider the QCTP to be the best value I've spent on tooling for both the lathe and mill combined. If I ever get a bigger machine, it will be getting one as part of the installation. Mine is Dickson clone, but I'd replace it with a wedge type, mainly because there are a number of special tools I think would benefit from being an integral part of the holder and dovetails are far simpler to cut.

The Dave Lammas toolpost design is three sided.

If you want a 4 way, and cannot find a suitable one (i.e. Straight fit, or can be modified to fit ) you can always make one.

Simplest way may be three laminations (2 large, 1 smaller ) to produce the slot, and maybe another to get the slot somewhere near the right height for the tooling.

My rear toolpost started life as a length of ground or fine milled steel, but finished up as a total of five laminations, including the base.

The laminations are held together, internally, by three long capscrews, the fourth "corner" being used for the dowel that controls the indexing. The post rotates about a silver steel dowel, secured to the base by a countersunk capscrew.

For a friend's Raglan, I machined one from solid, but that was a comparatively shallow post, again using a dowel for indexing.

Howard

As a kind of postscript;

I've stumbled across the descriptions of a couple of 'cheap' QC toolposts, the bodies (and maybe holders?) appear to be 'aluminium' - whilst I'm sure that they are well engineered and perfectly adequate, I hadn't until now realised that this was a thing - for long term durability and potentially demanding use I think the all-steel models are probably a much better buy, even if the cost is more.