ER16 Collet System for Sherline Machines

From left to right, tailstock toolholder, rotary table workholder and lathe/mill headstock work/toolholder.

The underside.

Making these was about the limit my Sherline lathe could manage.

There is no back gear on a Sherline and you have to wind the spindle by hand when single pointing. The M22 x 1.5 thread took around 80 passes for each one. After around 60% in, DoC is 0.01 mm per pass plus a spring cut in every 4 passes. Lovely clean snug thread though.

Also drilling the 8mm x 40mm deep thru holes prior to boring put a real strain on the motor.

Steve

Edited By Steve Crow on 30/06/2023 18:55:44

That just goes to show what persistance and patience can achieve, well done.

For the headstock adaptor I didn't have a tool to single point the internal 3/4" x 16 tpi thread so I modified a Sherline 10mm end mill holder similar to the 8mm next to it below.

First I had to plug the holes. I made mild steel plugs for the tommy bar holes, hammer tight fit plus loctite.

I single pointed a very snug grub screw for the threaded hole (1/4" UNF), screwed in with loctite and then filed off the slotted end. After turning and boring to final diameters, they were barely visible.

Here it is on the headstock. It's milled for 22m a/f spanner.

I bored the taper in situ so there is now just a twitch of runout.

I can also fit it to the rotary table using a chuck adaptor. Not sure about the runout yet though.

I've tried to make the most compact and simple adaptor possible and also retain the full thru spindle diameter (10mm). This is about as short as you can make it (30mm) before the collet fouls the spindle. I've already used it for drilling on the mill. Gives me much more headroom than a Jacob's chuck.

Steve

Nice to see your persistence pay dividends

re: drilling

Use GOOD drills, presto dormer stuff puts far less stress on a teeny machine

There is a lot of import rubbish about, even my "decent" Lidl ones need sharpening far more often than the good stuff

GL

edit and learn to grind properly, backing off the point and the trailing flute can make a big difference

Edited By Ady1 on 30/06/2023 19:46:09

Bravo, Steve !!

Lovely job done using an ‘unreasonably small’ machine.

MichaelG.

I do try to use goog drills. I have a "special" 8mm that's very sharp that I save for pre-boring like this. I'd get nowhere with cheap ones on this machine.

Steve

The tailstock chuck was the most straight forward to make. It started as a 40mm length of 1" EN1A.

Concentricity wasn't critical on this one as it fits in an adjustable tool holder. I did my best though.

Steve

Edited By Steve Crow on 01/07/2023 10:18:27

I had to make the rotary table adaptor in two parts. The flange was made from a 50mm x 10mm aluminium disc. It's been drilled and counterbored to accept 4 x Sherline T-nuts.

The spigot on the bottom is a few hundredths smaller than the table centre bore with a thru hole of 8mm.

When mounted, a couple of minutes with a clock and a small nylon hammer and you can just about eliminate any runout.

By the way, I'm using ball bearing collet nuts for all the adaptors.

Steve

Very nice Steve, and a lot of patience .. 80 passes for the thread .. by hand.. fair play.

Worth it though

I sometimes use those battery drills for "turning things" jobs to save my dodgy hands and wrists

18v 20v drills, brushless are best with loadsa torque

Used them mainly as power feeds on my milling setup, good slow speed torque control

Put an adapter on the back of the headstock spindle... and plug a drill on

You're quite a capable guy, just a thought to try and make life easier

The best thing of all is a hand crank setup

Edited By Ady1 on 01/07/2023 13:47:22