Milling a 45 degree 'v' slot

Hi Lee

Sorry no pictures. Not something I've done but its the way I'd do it if I had to.

Just one of several fairly complex things that folk do on a fairly regular basis that, for a long time, have make me think "must be an easier way".

Its easy to forget that what you are trying to do is make a functionally effective toolholder. If copying factory is too hard then cheat!

I should thank you for providing the opportunity to get off my tail and finally putting my thoughts all together in coherent fashion. I will say that it wasn't until I was about half way through that I cottoned on to how much a DRO can be a game changer in the real world. I'd pretty much always "sort of known" but I've got the gear to do it the old style way. Lots and lots of ££££ over several decades worth.

Clive

This is what I have in my head.

In what way would you use the DRO to build the sine plate?

John Reese, that matches with some of my bought toolholders which have a slot at the bottom of the vee. This is not necessary from a fit point of view as the peaks of the vees on the tool mount are truncated.

It does remind me of gashing a blank before cutting teeth on a gear using a form tool. I am starting to think that a form tool used like a fly cutter would be a relatively simple set up compared to all the messing around with angle plates, tilted head or special jigs. For a beginner grinding a HSS blank to two 45 degree faces should be quite simple, a home made holder based on a small fly cutter but not angled is an easy tool to make and there are lots of how to videos on using these types of tools to make gears. Spacing the vees becomes relatively simple as a result provided the tool is stiff enough for the necessary stick out for the two vees to be cut with just a move of the quill.

Martin C

Been out and mocked up this as an example.

Edited By Martin Connelly on 21/05/2020 14:23:04

Hi Guys,

I notice that nobody has commented about my suggestion of using a 45 degree countersink. HSS or Carbide.

Using one would mean that the work could be securely fastened down to the mill table without any messing about with the mill head and then having to tram it all up again.

Hello Martin, Guys,

That is basically how I cut the dovetails for this slide.

John, had to go back to page 1 to find it, I didn't see it because I was busy in the garden most of yesterday and never looked at the posts from then. It seems like a good idea to me. As in all these things there are probably hundreds of ways to do it and it's going to be up to the OP to decide what he can do and wants to do to get the work done. All we can do is suggest options until he decides on something.

Martin C

Lee

Got it in one!

The point about using a DRO is that it makes it pretty much routine to get the spacing of the two rods and the ledges they butt up against correct to any practical level of accuracy. Its equally easy to make the riser block required for whatever angle you want to sufficient accuracy.

Equally getting a nice regular pattern for the tapped holes is almost trivial. Consider locating dowel fittings to get the fence square or make the fence L section so the working part is above the table and trim it dead square in situ.

Plenty of variations on the theme to get the best balance between what material you have on hand, what machining facilities you have and what you plan to do. I'd probably make flat bottom Vee carriers for the rods with bolt holes to fix to the table or riser. Rods sticking out about 1" each side for clamps. Except for very shallow ones risers are probably most convenient to handle if made with tapped holes in top and bottom. Top ones take the Vee trough for the rod, bottom ones hold a plate extending either past the ends or to one side drilled so it can be bolted to the table. Shallow ones would need the fixing plate and riser made in one.

I'd make the riser in situ. Start with some stock a bit too deep, fit bolt holes, fix to base, bolt on machine table and cut it exact to size. Fit Vee troughs and sine plate and get to work.

Or you could make a complete unit on its own baseplate like the one in your picture. Invert it to bolt the riser on. Simply clamping the rods to a flat top ought to be satisfactory. Especially if you use the proper sine plate layout with deep ledges. Although I'd go for shallow ledges and a Vee trough but realistically its 6 of one half a dozen of the other.

Being a lazy type I'd probably base the device around a drilled and tapped 1/2" thick alloy breadboard from optical suppliers like Thor Labs **LINK** . The smaller ones aren't too silly spendy but double density versions might be a little too much. Something in the 8" x 8" to 10" x12", 200 x 200 mm to 250 x 300 mm might suit. The anodising is tough. Some stiffening underneath would be desirable for most jobs. Glued on strips perhaps.

The drilled and tapped breadboards are roughly comparable in price to 1" aluminium tooling plate or ordinary 25 mm steel plate so its not an unreasonable way to go about things.

So DIY "all new" you are in a similar price range to an import 4" tilt and swivel vice or a bit more than a swivel 6" vice. Much, much less if your finder-fu is good on used and handy scrap.

Its what I would do if starting out saving maybe £3,000 on stuff I'd most likely no longer need to have. Probably half of which I've not exploited. My finder-fu is usually pretty good too.

With a bit of creativity in the fence line, think limitless vice and carved in situ style, a device like this can make a larger machine vice unnecessary. If one piece style you can take it to the bench for preliminary set up too, of-times on a smaller mill the head gets in the way.

Clive

Going okay so far, but it's such a faff.

I still like the idea of a repeatable sine table based setup with stops, but I just can't picture what that would d look like without purchasing some kind of tilting table.

lee, have you worked out how to remove the pin from the post so that you can offer up the post to your holder at this stage for test fitting?

Doesn't quite work like that I'm afraid.

Thank you.

Er, T1 ish (?).

73mm long rings a bell, 35mm high, stock a 16mm tool slot/capacity.

Originally sold for Boxfords/Bantams etc.

Hi Guys,

Ooo bringing back all the memories of why I got rid of my QCTP.

Again, many examples of how ingenious members are in finding solutions to a particular problem.

Me? I either clamp the work in a vee Block in the milling vice, (Usually square material, or use my small three way tilting vice, instead of a tilting table.

Occasionally prop up the work with a centering square, an angle plate, or set it with a digital angle gauge.

But having said that, I am not very adventurous (and come to grief when I am ).

Howard

Forgot about that bit in the middle may be worth doing the tee slot first on the others?

So I just trammed the head back to 0° (vertical).

How does 0.1mm over 480mm sound? So 1mm over 4800mm (4.8m).

I fear this thread may get off topic pretty quickly.

If you'd like to follow progress or get involved in further discussions, I started a thread over at:

[Project 3] Dickson T1 Tool Holder

Lee I can't comment on what are good or bad figures for tramming, I have never had to do my mill as it does not tilt and it has always cut the correct circular pattern when using a flycutter. I know I'm probably lucky with this but it was a second hand machine and I don't know if it was done before I got it. Anyway I digress, the thing I was going to suggest is a nice piece of glass to put over the tee slots for the purpose of tramming. It will allow you to sweep the arm around without having to lift it over the slots. Modern float glass is pretty flat and of uniform thickness. If the tram is checked and then the glass is rotated 180 degrees and the tram re-checked it will show up any error in the glass. You may be able to use some from a picture frame but it may be a bit thin and so fragile.

Martin C

Really accurate tramming is a complete PIA job. Especially when you don't have a reliable, backlash free, screw controlled adjustment. Most home shop machines tend to be push'n hope adjustment so success is down to how many cycles of "nearly right, one more push, darn too far" you can cope with.

Bridgeports et al have a worm drive which is less effective than one might hope due to backlash and weight. Doesn't help that when set up in the usual manner Bridgeports, and other mill heads, tend to be in or close to balance when trammed. The motor assembly on Bridgeport style machines can be swivelled to one side allowing you to bias the weight significantly one way so you are always working against a stabilising load.

With the common ME size machines I'd be sorely tempted to hang a weight a foot or so out to one side on a suitable framework to bias things one way. Perhaps add a jack screw so you have positive control of the movement, or just arrange things so you have anice long lever to pull on. If nothing else a screw jack means you can let go without things moving on you. When I had a squarehead, Chester Lux style mill, I found it hard to hold the head steady whilst simultaneously tightening the bolts. Not enough arm joints methinks.

I'm inclined to think that a stout post with flat foot exactly at right angles grasped in a collet or, better, held in the spindle taper would be a quick way to produce tramming accuracy acceptable for most practical purposes. Basically bring the head down so the plate sits flat on the table. With the head bolts suitably loosened all should come close to aligned. I guess 6" or so diameter would do for the foot, bigger being better of course, so getting post and base mutually perpendicular is a simple lathe job well within the capability of most ME size machines.

Handy for taking the head off if need be too.

Alternatively perhaps a pin 'n slot pivot on a similar style post working in a bracket bolted to the table would give decent screw controlled movement.

Clive

Edited By Clive Foster on 22/05/2020 13:33:57