Dear Chuck, you are not the first to bore a hole to the od of a thread.....making me smile with you honesty.... wishing you and your wife a speedy recovery from the Covid ...best wishes, Paul

of course the collet pulls into the housing, that's why it has a taper inside the holder. so the collet as it moves in, is drawn tighter as it moves in the taper.

That type of collet stop obviously works fine on the 5C collets because there a single taper and close down right at the front of the collet. ER's don't work in the same way Chuck. They close on the tool shank or part from both ends. And the ER closing nut has to force the collet further into the chuck to get that closing force as the collet segments are wedged closed by the taper inside the collet holder or chuck, and the same at the front with the nuts inside taper. So yes an ER collet does move inward at least a bit. If they didn't they couldn't tighten as well as they do. Furthermore, ER collets require a tool shank or part length of at least 80% or more extending inside the collets total depth so it can grip at both ends of the part or tool shank. That's what provides the grip and stability on whatever there holding. Without that, concentricity and the full collet grip goes out the window since it's only holding at one end. And if the nut is tightened enough without anything at the rear of the collet to tighten against, collet segment damage or even breakage can sometimes occur. Yes 5C's do grip at only one end, but they only have a closing range of a few thou and not the full .039" or 1 mm each ER 32 can close. And that's why you don't see collet stops used on those ER collet blocks. A stop will work if it's only inside the rear of the ER collet by a very small amount. Visualize how an ER collet closes and you'll understand why they have that 80% or more rule. For anything that looks like a great idea and isn't commercially available, I always start out by asking myself why not. Most times there's logical reasons or I need more information before I can figure out why not.

Great idea about the 5c stops for the er collets. I find myself constantly looking at old videos from Tom Lipton, Joe Pie, and so many others.

As usual you win in the end. Thanks for the video keep on keeping on.

Nice approach, Chuck. Enjoyed.

Hey Chuck, great idea. I wish I could blame my dumb mistakes on Covid! There's a page in the Engineers Black Book with the calculation for depth of thread. I printed it on some label tape and put it on one of wall charts for ready reference.

Gday Chuck, that Covid is bloody nasty but it’s good to see you back at it again, top job on the stop, cheers

I like it. I watched Matty also and knew there had to be a better way. My problem is that I am using ER40 collets. I actually have a 5C lathe chuck video in the works. I will start there. Thanks for sharing.

Since the ER32 collet is held by the nut, it has to be pulled back into the block when tightening it.

If you think about it, 5C pulls in and ER nut pushes in the collet into compression. So from a stationary perspective, the collet moves towards the spindle under compression but ever so slightly.

The good thing is owning a machine shop , all mistakes are fixable. Don't beat your self up we all make them same mistakes.

5C Collet Work Stop Mr Pragmatic Lee made one pretty well the same seven Years ago.

Slick trick, Chuck. Thanks for sharing.

thanks for the info Chuck, cheers from Florida,Paul

Covid is no fun for sure - Hope your wife recovers as quickly. Great idea Chuck on modifying the collet blocks (you even get an extra opportunity to rework one 😉). I would have guessed that the blocks were hardened, but maybe not. I’m adding this to my to-do list. 👍😎👍

Get well!

Get well Chuck! nice show. you can always use a pin gage and an indicator to show us how much the part moves back as it is tightened :) ?!?! yes, 5c do pull back till the dia is gripped. but the stop inside moves back as well. larger dia part = shorter part, smaller dia part = longer part. I suspect some movement in a non stopped er system and potentially one in a stopped system. the collet does retract in an er but like the drawing in of a C type. using a hard stop always has its challenges based on the dia of the part. you can test that by using over/under pins. typically part tolerances on over all length are a good margin. it is just that each step can add additional error to a finished part.

I think a lot of people have missed the idea that in manufacturing a 5C collet is compressed and then bored to its nominal size.At that size it will be parallel.

good job chuck

Good info, thank you Chuck.

Good to see you are on the mend 👍👍Nice idea adapting the 5C stop for the ER32 ATB....

Glad to hear you are recovering and commiserations on getting china flu in the first place. Re the tapping size, it is the same principle as metric where you subtract the pitch ftom the diameter, like you drill 8.5mm for an M10x1.5(10-1.5=8.5) just the same with IMP but you use 1 ÷ tpi to give the pitch.

Thanks for sharing

I cought covid two years ago. I felt crappy for four days. Last year I was really sick. It was a cold. I just received my first er collets. The holder is two weeks late and still not here. I can't try them out yet. Take care Chuck

Good to see ya chuck

one of the beauties of a collet like the ER, is that you can hold longer materiel...I've been thinking about a way to have a collet stop that can allow for longer pieces of stock than yours and Matty's solutions can accommodate. Similar to Matty's design, but with the insert being longer and bored out to accommodate stock diameters up to the limit of the ER40 (1-1/8"). Not hugely longer, maybe 6 inches or so...

You aren’t the first guy to over size the bore when threading. Ask me how I know. Glad you are on the mend.

Good one! Do take care of your health and the wifes'. Thanks!

The advantage of the stop on a 5C collet is the stop threads into the collet itself. As the collet is closed, the stop and part do not move in relation to each other. This is true whether the 5C collet and stop is in a lathe or some type of fixture like a collet block. This isn’t the case where the stop is part of the collet block like in your ER collet design.

Thanks for sharing, even if the math is off a bit (blame it on COVID). The pitch for 24 tpi is not 1/16”, that would be correct for 16 tpi.

The quick and dirty is to use the calipers to measure across the valleys of the male threads

Glad you are feeling better, and I hope your wife feels better soon too! Bozo visits us all.

He wrote it because it does move just not as much as the 5c

by the way, nice jacket.....wonder where you might have scored that, you must have been hanging out at Lawrence Livermore Labs or something...

Make a collet tube to suit the oversize hole.

Movement of the Collet😅 ?? Perhaps! With the STOP, the Collet may move,😁 but the workpiece will not. At least, not my ER Collet stop.😊😊😊

I got Covid last year and my throat felt like fire every time I swallowed for about 3 days. Not no fun, anyhow.

This geriatric vaguely remembers the in and out, inandout that you mentioned...but alas and alack, such things are a figment of the past...

Boring too wide.... or boring through when making a blind hole..... "Brain slip' we say here, home brew translation. Have to check my gear for that improveme t.

Got the jab 2 times, still got covid 2 times .