Hi,

Does anybody sell metric collets for the non ER mill spindle? Using the 0.001" over and 0.004 under rule on the Taig site nominal metric sizes (4, 5 & 6mm etc.) fit nicely between the imperial collets!

Cheers,

Unfortunately I've not seen any and I have seen others buy the collet blanks and machine them to fit their needs, so possibly you could do that?

If not, maybe a bushing that you make and slit would be a quick and easy work-around?

Dave

Many thanks Dave.

My only concern with making my own is drilling the hole dead centre in the collet. Slightly out and the tool will run eccentrically.

Cheers.

I've attempted to make a few of my own collets (metric). I find the drilling is easy enough. Just mount the blank collet in the spindle on the lathe and then use the tailstock with drill chuck. Best to use a centre drill first to start it off, then the metric size drill you want . Make sure the taper in the spindle is free of any bits of metal etc. - This got me and I ended up with a slightly eccentric one (live and learn)

The tricky part is cutting the slots in the sides of the collet. I have yet to master this. I have seen somewhere that someone made a jig. But it seems to hold the collet at the very end, and I would hate using a slitting saw on something that was going to fly out of the jig!!! So I hacksaw the slots in. These look real messy, but because the hole is centered it doesn't matter. They do the job fine.

Thanks for your response DavDu. Unfortunately, I don't own a lathe.

Cheers.

Can't you mount the blank in the spindle and hold the drills in the vise?

Dave

Ah yes, no lathe presents problems alright. As fretsman says, you could hold the drills in the vise - or manufacture something to hold them dead vertical. Of course the next problem is aligning up the collet centre with the drill. I was thinking - if you put the collet closer onto the spindle (with no collet in) and used an electronic edgefinder with the drill slightly inside the round hole at the bottom of the collet closer. This should let the drill find the very centre of the collet closer. Then move the z-axis up and put in your blank collet, then drill. How does that sound???

Another option is to use solid tool holders: http://soigeneris.com/A2Z_ToolHolder.aspx . The are available in 3mm & 6mm sizes. They would be much easier to bore out to larger sizes than a collet would be.

I actually use a hacksaw for cutting the slots in the collets. It is not the most accurate method, and the finish looks messy. In my opinion it doesn't have to be that accurate anyway. Once the hole is spot on, thats all that matters. I do have another project lined up that holds collets though. Check out this website.....http://unitaig.jalling.dk/index.php?id=99

Although this holds the collet so you can use a slitting saw, it seems to only grip the very end of the collet - especially when gripping the smaller diameter end. I guess advancing the slitting saw should be taken very slowly and carefully.

The tools do need the 'weldon' flat, or you can modify them like Dave said. This is how most solid tool holders work.