Model 9A Collet attachment allows end mill to slide back into collet

two-can · Dec 12, 2017

Today I was using a 1/2" end mill to mill a 1/2" plate to a smaller size, and it started out ok, but after a while the end mill would slide into the collet and pull away from the work.

I tightened the collet up until I feel a "stop" at the end of the threaded area, and the end mill seems to be held pretty tight.

Is this a normal problem or is there some adjustment that I am not making? Is it possible that trying to cut 0.025" on a single pass at 633 rpms and 0.019" per revolution feed rate is too much?

Could the cutting oil be working up into the collet along the end mill shank and allowing it to slip?

Seems like this should be a simple set up,but not so far.

Monarchist · Dec 12, 2017

two-can said:
Today I was using a 1/2" end mill to mill a 1/2" plate to a smaller size, and it started out ok, but after a while the end mill would slide into the collet and pull away from the work.

I tightened the collet up until I feel a "stop" at the end of the threaded area, and the end mill seems to be held pretty tight.

Is this a normal problem or is there some adjustment that I am not making? Is it possible that trying to cut 0.025" on a single pass at 633 rpms and 0.019" per revolution feed rate is too much?

Could the cutting oil be working up into the collet along the end mill shank and allowing it to slip?

Seems like this should be a simple set up,but not so far.

You were fortunate it was driven back into the collet. "Pull out".. where the endmill digs into the work at its own choice of advancement and ultimate depth, is far worse.

Many mill hands try really hard to not USE collets to hold end-mills. Weldon-style side locks, rather.

There are types "out there" than can be fitted to a lathe-abused-as-mill. Taper-adapter, and - please - also a drawbar. You'll be glad of having that, even if you have to fab a DIY one out of allthread, nuts, and warshers.

kitno455 · Dec 12, 2017

Possible that some part of the thrust washer is missing from your collet closer. Make a temporary spacer to fit between the shoulder on the closer and the end of the spindle, and see if that improves things.

allan

two-can · Dec 12, 2017

Here is a photo of my setup. I believe it is an original South Bend attachment.

two-can · Dec 12, 2017

kitno455 said:
Possible that some part of the thrust washer is missing from your collet closer. Make a temporary spacer to fit between the shoulder on the closer and the end of the spindle, and see if that improves things.

allan

Thanks, Allan.

I'll give that a shot and if it would help me to further tighten the collet around the mill, it might prevent any movement of the end mill. As I said, it started off working very well.

Rudd · Dec 12, 2017

Monarchist is correct, end mills are bad about sliding in collets. An EM holder is much better.
Having said that, I am short of headroom on the vertical mill. I use ER's.
One trick I picked up is to make sure everything is oil free, and dust some chalk on the shank of the EM. The marking chalk for string lines is conveniently packaged for this use.

two-can · Dec 12, 2017

What is a reasonable depth of cut when using a collet setup like this?

kitno455 · Dec 12, 2017

Oh, I did not realize this was a lever closer. Please tell me you are pulling the lever?

allan

Monarchist · Dec 12, 2017

two-can said:
What is a reasonable depth of cut when using a collet setup like this?

Pragmatically, for a 1/2" endmill, there is no "reasonable" depth of cut with that rig.

- the collet system is too small for decent grip PLUS ability to transfer motive power. 1/4" EM and below, lighter cuts, more of them, more time allowed to complete the job, you could be better-off. Or you could STILL have it pull the endmill into the work.

- The carriage & cross don't have the "meat" where a milling machine puts it, are optimized to manage the different force-vectors of single-point lathe turning, not those generated by milling.

- More stress yet comes from the reality that ANY milling operation, fly-cutter to multiple insert face mill, is an "interrupted cut", too. The cutter flutes 'pound' even if the material does not.

Some of the same issues affect trying to mill with a drillpress and X-Y table. Not built for side-thrusts. Not ordinarily provided with pull-out resistant tool retention system.

Bad idea, in general. Sometimes VERY bad. Even so.... it usually works better than a milling attachment for a light lathe.

Blob · Dec 12, 2017

I agree with Monarchist - get yourself an end mill holder and save yourself some grief - they are readily available and not expensive.

two-can · Dec 13, 2017

Monarchist said:
Pragmatically, for a 1/2" endmill, there is no "reasonable" depth of cut with that rig.

- the collet system is too small for decent grip PLUS ability to transfer motive power. 1/4" EM and below, lighter cuts, more of them, more time allowed to complete the job, you could be better-off. Or you could STILL have it pull the endmill into the work.

- The carriage & cross don't have the "meat" where a milling machine puts it, are optimized to manage the different force-vectors of single-point lathe turning, not those generated by milling.

- More stress yet comes from the reality that ANY milling operation, fly-cutter to multiple insert face mill, is an "interrupted cut", too. The cutter flutes 'pound' even if the material does not.

Some of the same issues affect trying to mill with a drillpress and X-Y table. Not built for side-thrusts. Not ordinarily provided with pull-out resistant tool retention system.

Bad idea, in general. Sometimes VERY bad. Even so.... it usually works better than a milling attachment for a light lathe.

I agree, but since I do not have a milling machine, I am kind of stuck with doing this small job on the lathe. My hope is to finish this tee nut, and get back to turning, not milling.

As people say, there is no free lunch.

Monarchist · Dec 13, 2017

two-can said:
I agree, but since I do not have a milling machine, I am kind of stuck with doing this small job on the lathe. My hope is to finish this tee nut, and get back to turning, not milling.

As people say, there is no free lunch.

No need of a mill for that. A Tee-nut can be turned on a lathe, then squared-off with an ignorant hacksaw or chop-saw & the touch of a file. Plenty of examples about. "Right here on PM", and with good photos, too.

FWIW-even-less-department.. for a 10EE that HAD NO toolpost or ANY tooling, I made the first one of mine with a Lowe's Kobalt carpenter's miter-saw with a jury-rigged "depth setting", used-up-anyway carbide blade, welder's gloves and doubled-up eye protection to manage the hot ejecta. The 10EE was not YET in a position to hold an opinion, let alone a cutting-tool. And then it was...

two-can · Dec 13, 2017

Monarchist said:
No need of a mill for that. A Tee-nut can be turned on a lathe, then squared-off with an ignorant hacksaw or chop-saw & the touch of a file. Plenty of examples about. "Right here on PM", and with good photos, too.

FWIW-even-less-department.. for a 10EE that HAD NO toolpost or ANY tooling, I made the first one of mine with a Lowe's Kobalt carpenter's miter-saw with a jury-rigged "depth setting", used-up-anyway carbide blade, welder's gloves and doubled-up eye protection to manage the hot ejecta. The 10EE was not YET in a position to hold an opinion, let alone a cutting-tool. And then it was...

Thanks again, Monarchist.

I appreciate your knowledge and experience.

My term Tee nut may not be descriptive enough as it is 2.5" long, and I was hoping to make a semi professional job rather than the ones that I made for my drill press using a file and vise prior to obtaining this lathe.

This morning I tightened the knob on the pull bar AFTER I pulled the lever to lock the end mill in the collet and it seems to be holding quite a bit better since I also lowered the feed rate by 25%

While it is slow doing it this way, I look at it as "learning time" rather than wasted time, and thanks to the contributors on this forum, I am learning quickly.

jim rozen · Dec 19, 2017

"This morning I tightened the knob on the pull bar AFTER I pulled the lever to lock the end mill in the collet and it seems to be holding quite a bit better since I also lowered the feed rate by 25%"

You are still going to have a rough time of it doing the collet this way.

1) slack the collet closer knob and move the lever to the right.

2) put the end mill in the collet.

3) attempt to slide the lever to the left to lock the closer over center.

if the lever stalls before it snaps over center, slack the closer knob more.

if the lever moves full left without grasping the end mill, tighten the closer knob and try again

key is to find that one spot on the closer knob adjustment so the snap of the closer grabs the
end mill properly. You can NOT hold any tool or workpiece in a lever acting collet setup, by
simply tightening the knob by hand. You MUST have the lever snap over center to get a good
grab.

For any reasonable feeds and speed with a milling attachment like that, you will shift the milling
attachment on the slide before you begin sucking the end mill from the collet.

two-can · Dec 20, 2017

Thanks, Jim
You are right, this method proved to be very unsatisfactory. I ended up spending over 3 hours filing the piece by hand to finish it, but at least it now provides a secure mount for my new tool post.

I was hoping that I would be able to do some light milling jobs on this lathe, but maybe it was just a pipe dream.

Thanks to everyone who commented on this post.

jim rozen · Dec 20, 2017

A lever closer is a vital part of your lathe. If it cannot hold an end mill, it can't hold a workpiece for you.

Unless there is something missing or defective, it should work as advertised.

two-can · Dec 20, 2017

jim rozen said:
A lever closer is a vital part of your lathe. If it cannot hold an end mill, it can't hold a workpiece for you.

Unless there is something missing or defective, it should work as advertised.

I will check that out today, as I really want to do some light milling operations on the 9A. Is there a particular spec that is available to check the tolerance of the various pieces of the lever closer?

two-can · Dec 20, 2017

Upon some research and a closer inspection of my Lever Closer and the end of the lathe spindle, it appears that the closer only goes up to the end of the chamfer on the spindle. There is a slot in the Closer but no pin or hole on the end of the spindle, and the Closer does not go up to the start of the gear teeth as is showh in some of the 10K 5C collet closer.

I also saw a comment that the Closer is just about a "press fit" onto the spindle.

When I was using the collet attachment to mill a 1/4" slot on a 3/8" x 2.5" piece of steel, I found that the Closer was driven onto the spindle when I tried to make a deeper cut into the material. (after tightening the hand knob after lever was set)

What is the correct installation for a Model 9A and a 3C collet closer attachment? How different is it than one for a 10K (other thab the larger diameter)?

Monarchist · Dec 20, 2017

two-can said:
Upon some research and a closer inspection of my Lever Closer and the end of the lathe spindle, it appears that the closer only goes up to the end of the chamfer on the spindle. There is a slot in the Closer but no pin or hole on the end of the spindle, and the Closer does not go up to the start of the gear teeth as is showh in some of the 10K 5C collet closer.

I also saw a comment that the Closer is just about a "press fit" onto the spindle.

When I was using the collet attachment to mill a 1/4" slot on a 3/8" x 2.5" piece of steel, I found that the Closer was driven onto the spindle when I tried to make a deeper cut into the material. (after tightening the hand knob after lever was set)

What is the correct installation for a Model 9A and a 3C collet closer attachment? How different is it than one for a 10K (other thab the larger diameter)?

Kinda hoping for a Unicorn to come into the milking stall, here, are you not?

If you really MUST use the 9A for milling... Why not use a Weldon style side-lock holder and DIY drawbar so you do not have to use the collet closer system AT ALL?

If you cannot find one to hold a 1/4" (or smaller) endmill that already fits the 9A's internal spindle taper - with MT adaptor / sleeve, if need be - it shouldn't take a 9A very long to make one.

Outer taper turned 'tween centres, endmill hole and drawbar hole bored in-situ, second one tapped. A cross hole for locking setscrew drilled and tapped.

No more push-back or pull-out issues atall. Stronger and stiffer, too.

I'd not waste the time, actually.

I have both square and hex collet blocks in both 5C and ER that can be gripped in a 4-jaw. Those are general-purpose problem-solvers, so are easier to justify making an investment in, long-term.

2CW

Monarchist · Dec 20, 2017

jim rozen said:
A lever closer is a vital part of your lathe. If it cannot hold an end mill, it can't hold a workpiece for you.

Unless there is something missing or defective, it should work as advertised.

Not so sure about that. Trying to hold an endmill is abuse of a spring-collet, IMNSHO, and I'd not really give a free pass to an R8, either. Even Bee Pee's are better served with R8-arsed Weldon milling cutter holders than R8 spring-collets.

Model 9A Collet attachment allows end mill to slide back into collet

Plastic

Diamond

Titanium

Plastic

Plastic

Stainless

Plastic

Titanium

Diamond

Hot Rolled

Plastic

Diamond

Plastic

Diamond

Plastic

Diamond

Plastic

Plastic

Diamond

Diamond

Similar threads