Collet Block in Vertical Slide

[PaulR]

The vertical slide I bought a couple of weeks ago will mostly be used for cutting slots and a few tests shows it works well enough. The slide is similar to this one with a 2" vertical space in which to clamp stuff using the three screws:



I was thinking of buying a 2" vice to to the actual work holding, turned on its side to clamp into the slide (actually the aperture measures about 49.6mm so I'm not certain a 2" vice would fit).

However, I'm wondering if it would be just as easy to use parallels and packing to hold flat parts and instead of a vice for holding round work, buy a collet block like this (which being 45mm AF would definitely fit and leave space for packing on top to spread the clamping force).



I've never used collets before so I have a few questions if anyone can advise...

Does the above block just require spring collets like the one below (and a spanner) inserted and tightened from the front? I've seen some where the collet is drawn in from the back which won't work for me.
Are they usually a standard size from front to back that will fit entirely within the block?
Will having the back of the block against the back of the aperture and all three screws tightened onto some packing on top be enough to resist any turning force if cutting a slot horizontally?

I might still get the vice anyway but any advice is welcome!

[Jasonb]

The ER collet blocks use ER collets like you have shown, available in ER25, 32 and 40 with ER32 being the most common.

The collet is snapped into the nut and then tightened from the front.

Only seen them done in one length proportional to their size which would stick out quite a bit from your Vert slide. Is it possible to mont the slide so that you can have the longer length of the collet block held rather than the end?

I would be tempted to machine the two "jaws" of the moving part of your vertical slide, then drill and tap for some hold downs and also to be able to mount a small vice.

[ShopShoe]

If those are ER collets and collet block, they clamp from the front, using the clamping nut to tighten.

ER collets have an ability to compensate for small differences in diameter of whatever you want to clamp, allowing a set of collets to provide an almost infinite range of material size that can be clamped. The "basic" size of each collet can be in either the imperial or metric range.

To answer your question regarding their use with the vertical slide:  I think that a square collet block might work in the slide's clamp, but a hex or octagonal block might not be secure enough to stand the stress of machining in certain situations.

You are getting in a situation where leverage comes into play. The force generated by the operation in use will be greater the further you get from the screws that hold the collet block in the vertical slide.

I think the vise is a good option, and you might want to add the collets. Just be careful not to create a sketchy setup which at minimum could ruin your part or cutter and at maximum could hurt yourself or anyone else.

--

If you have thread-cutting options on your lathe, you might find the following article on making an ER collet holder interesting:

https://www.homemodelenginemachinist.com/threads/building-an-er-collet-chuck-from-scratch-for-a-myford-ml7.5179/#post-59801

I have a 7x mini lathe and I worked through this process myself to make an ER11 collet adapter myself to use in that lathe and on my mill. It was a good learning project a few years back. I did have more than one do-over step in my operations.

Please let us know what you decide and show your work.

ShopShoe

[PaulR]

The ER collet blocks use ER collets like you have shown, available in ER25, 32 and 40 with ER32 being the most common.

The collet is snapped into the nut and then tightened from the front.

Only seen them done in one length proportional to their size which would stick out quite a bit from your Vert slide. Is it possible to mont the slide so that you can have the longer length of the collet block held rather than the end?

I would be tempted to machine the two "jaws" of the moving part of your vertical slide, then drill and tap for some hold downs and also to be able to mount a small vice.

Thanks for this. Do you mean mounting the block perpendicular to the lathe axis so the collet would be facing me (which would probably allow two of those screws to make contact) like this?

I haven't done any milling in this yet only 3mm slot cutting, I don't fancy potentially trashing the slide by machining it before I've started 

[uuu]

If you could buy or make a low-height vee block, you could mount round work directly in your vertical slide, with the three screws clamping it down.

Wilf

[PaulR]

If those are ER collets and collet block, they clamp from the front, using the clamping nut to tighten.

ER collets have an ability to compensate for small differences in diameter of whatever you want to clamp, allowing a set of collets to provide an almost infinite range of material size that can be clamped. The "basic" size of each collet can be in either the imperial or metric range.

To answer your question regarding their use with the vertical slide:  I think that a square collet block might work in the slide's clamp, but a hex or octagonal block might not be secure enough to stand the stress of machining in certain situations.

You are getting in a situation where leverage comes into play. The force generated by the operation in use will be greater the further you get from the screws that hold the collet block in the vertical slide.

I think the vise is a good option, and you might want to add the collets. Just be careful not to create a sketchy setup which at minimum could ruin your part or cutter and at maximum could hurt yourself or anyone else.

--

If you have thread-cutting options on your lathe, you might find the following article on making an ER collet holder interesting:

https://www.homemodelenginemachinist.com/threads/building-an-er-collet-chuck-from-scratch-for-a-myford-ml7.5179/#post-59801

I have a 7x mini lathe and I worked through this process myself to make an ER11 collet adapter myself to use in that lathe and on my mill. It was a good learning project a few years back. I did have more than one do-over step in my operations.

Please let us know what you decide and show your work.

ShopShoe

Thanks for the detailed reply. Yes, those are ER32 collets. I did look at the square block but thought the hex one could be more useful but as you say, it offers less surface area to grip. I don't envisage taking any cut deeper than about 0.005", mostly for 2 to 3mm slot drills and nothing bigger than a 6mm endmill for the odd bit of flat milling. Materials would be brass and mild steel. I've tried a couple of 3mm test slots in flat brass clamped using those screws and a packing piece on top and it worked better than I expected. It's holding round work that I'm trying to figure out the best option for.

[PaulR]

If you could buy or make a low-height vee block, you could mount round work directly in your vertical slide, with the three screws clamping it down.

Wilf

Thanks Wilf, that was my first thought but I would have to work out if the vee block clamp would be in the way... hard to tell without having all the bits in hand to look at.

[uuu]

I was thinking the vee-block would not have its own clamp.  I'm thinking a very low block - effectively a short length of bar with a shallow vee machined down it.  The the vee facing up, the three screws would bear down on your round bar.   If you make your own vee block, you can arrange the vee to be the same distance from the back edge as the three screws are within the gap, so the vee will be directly below them, and always square to the vice.

Wilf

[PaulR]

Just had a look around and there are some vee blocks as small as 32mm square. I suppose I could discard the vee block's clamp and use the central screw to hold the work (and vee block) and the other two screws to hold packing either side to stop any rotation.

[PaulR]

I was thinking the vee-block would not have its own clamp.  I'm thinking a very low block - effectively a short length of bar with a shallow vee machined down it.  The the vee facing up, the three screws would bear down on your round bar.   If you make your own vee block, you can arrange the vee to be the same distance from the back edge as the three screws are within the gap, so the vee will be directly below them, and always square to the vice.

Wilf

Posted my reply at the same time! Yes, this sounds like a very good solution, I just need to work out how to hold a piece of steel at the correct angle to mill the vee (the slide does rotate but I've never used that option). On reflection I don't think that's possible without a chamfer milling tool.

[PaulR]

Wandering a bit off topic from the original post because I can't think of a way to cut an accurate vee, these two simple contraptions from an old Geometer article look like they would do the job for holding round bar to mill or slot the ends, the one with the angle being less likely to mark the surface I suppose. Either could be made to centre directly under the three screws for clamping. Hmmmm, lots of options!

[Jasonb]

Yes, hold as you sketch in red pen. The vert slide should be able to rotate to you could use it for both cross drilling as well as working on the end or round stock. Another advantage of holding it that way is you can work on the end of longer material.

You can also get Vee blocks where the clamp screws to the top rather than hooking around the side so that may be another option.

As for cutting a vee, rotate the vert slide so it is 45degrees on the cross slide, clamp a block of metal in it's jaws and move the work up and down against a cutter in the lathe chuck.

[PaulR]

Yes, hold as you sketch in red pen. The vert slide should be able to rotate to you could use it for both cross drilling as well as working on the end or round stock. Another advantage of holding it that way is you can work on the end of longer material.

You can also get Vee blocks where the clamp screws to the top rather than hooking around the side so that may be another option.

As for cutting a vee, rotate the vert slide so it is 45degrees on the cross slide, clamp a block of metal in it's jaws and move the work up and down against a cutter in the lathe chuck.

Thanks again. Will have a good look at what's available at the show on Thursday then decide which way to go. The slide only rotates around the horizontal axis not the vertical BTW.

[Jasonb]

Does it not rotate like your lathe topslide as it uses the same two fixings? Or does the fixed vertical part come too low?

[PaulR]

Does it not rotate like your lathe topslide as it uses the same two fixings? Or does the fixed vertical part come too low?

There's a projection of 1/4" or more that will collide with the cross slide casting. TBH I only expected it to rotate as it does, I never considered rotation around the vertical axis.