Premium ER collets

[wmpy]

Who makes a good ER collet with low runout? REGO-FIX? Techniks? Or do you guys have good success with the Maritool collets?

I had a job running great- incredible tool life, good chip formation, good cycle time. I was happy. Then, the 5/16" solid carbide 3-flute end mill that I'm slotting with snapped about 1/4" into the collet, destroying the collet. The tool honestly didn't even look that bad, but I had made 10k(!!!) parts with this end mill, so I guess I had found the limit of the tool. Now, with a new collet and the same type of end mills, I am getting chipping on 1 or 2 teeth of the end mill after a short time. I had bought a collet from YG-1, which I suspect is giving me runout problems. A gage pin tightened in the holder is giving me .001"-.003" runout about an inch from the collet face. So, I'd like to get a really good collet just to eliminate that as a problem in case I'm dealing with other issues here.

This is on a live tool lathe, so I have to stick with the ER20 collets that the holder uses. I checked my holder after the tool snapped, and it's fine- couple tenths runout and no slop in the bearings. The collet nut might be a problem as well. It's a two-piece nut, and the inner piece is stuck pretty good in the outer piece. It's acting like a one-piece nut. Does anyone have any tips on freeing those seized nuts? I took out the set screw in the side and was able to get one of the balls out, but the others aren't coming. There are a lot of fine chips in there.

I'm not using a torque wrench to tighten the collet nut. Should I be using one?

 

[TeachMePlease]

You want Rego-Fix part number 1120.07943. That's their UP (Ultra Precision) ER20 5/16" collet.

 

[DouglasJRizzo]

I'd vote for Rego-Fix or Schaublin. Dad had both and they worked very well for accuracy.

 

[Mechanola]

Rego-Fix was the inventor of the Extended Range collet. The precision encloses more than the collet alone, you need a good holder and a cap with nicely ground internal taper as well. Cleanliness is important, too.

I never slot with an endmill.

 

[Milland]

I'll bet money it's the nut that's shoving the collet over. Measure the threads of the ER20 adapter, hopefully they're a common series, in which case you can replace the nut with a quality single-piece from Techniks or whoever.

Buy two collets of the size you need, check them both, and when you find a good runnout (maybe with a little rotating of the collet within the taper) mark it such that you can repeat the orientation.

 

[wmpy]

I'll bet money it's the nut that's shoving the collet over. Measure the threads of the ER20 adapter, hopefully they're a common series, in which case you can replace the nut with a quality single-piece from Techniks or whoever.

Buy two collets of the size you need, check them both, and when you find a good runnout (maybe with a little rotating of the collet within the taper) mark it such that you can repeat the orientation.

Hey Milland. I should have mentioned that I have a brand new Maritool one-piece nut that I tried and that gave poor runout readings with a gage pin. I could compare it to my seized two-piece Alpstool nut to see if there is any difference.

 

[wmpy]

You want Rego-Fix part number 1120.07943. That's their UP (Ultra Precision) ER20 5/16" collet.

Thanks, Teach. I'm getting one quoted now.

 

[crossthread82]

Thanks, Teach. I'm getting one quoted now.

Regofix UP collet and a regofix nut is the best bet, they make the best ER stuff IMHO.

 

[gkoenig]

Regofix UP collet and a regofix nut is the best bet, they make the best ER stuff IMHO.

Almost like the R in ER is for Rego...

 

[wmpy]

Do you guys like the two-piece nuts, or do the one-piece nuts work fine?

 

[Orange Vise]

Then, the 5/16" solid carbide 3-flute end mill that I'm slotting with snapped about 1/4" into the collet, destroying the collet.

Now, with a new collet and the same type of end mills, I am getting chipping on 1 or 2 teeth of the end mill after a short time.

What material? Aluminum?

Are the endmills from the same or a different batch?

 

[Orange Vise]

Do you guys like the two-piece nuts, or do the one-piece nuts work fine?

One's fine in most applications, especially a live tooled lathe.

The purpose of two piece nuts is to prevent twisting of the collet under max torque.

 

[Orange Vise]

Rego-Fix was the inventor of the Extended Range collet.

Almost like the R in ER is for Rego...

I believe the story is that "E" collets were common at the time (late 60s?) but didn't have a built-in ejection mechanism. You had to knock em out from behind, similar to how you knock the drawbar on an R8 Bridgeport.

Rego added the groove and the eccentric ring in the nut, and also added the "R" to ER. Patented it in '72.

 

[wmpy]

What material? Aluminum?

Are the endmills from the same or a different batch?

The material is soft 4140. I'm using an axial holder to cut a 5/16" wide groove that is a little over 1/2" deep in the end of a 5/8" round part. The slot goes all the way through the part. Think of a tuning fork or an old clothespin.

I verified with the manufacturer that all the end mills are from the same batch. I haven't completely ruled them out, but I don't think they're the problem.

 

[wmpy]

Rego-Fix was the inventor of the Extended Range collet. The precision encloses more than the collet alone, you need a good holder and a cap with nicely ground internal taper as well. Cleanliness is important, too.

I never slot with an endmill.

I imagine that your preferred method to slot would be a slotting saw or milling cutter, but I don't think my live-tooled lathe would have the power to pull one of this size. We used to use a milling cutter when the slotting was done in a mill, but now we're making these in one shot off the bar.

 

[DavidScott]

Do you guys like the two-piece nuts, or do the one-piece nuts work fine?

One piece! The ball nuts are great, until contaminated. Plus they are fatter/taller which I find a detraction. A little oil on the nut taper helps when assembling, and I always use a torque wrench to tighten the screws or nuts. How else do you know if the torque is correct or even consistent?

I like the cheaper SYC collets, for the $$, and get between .0002"-.0004" of runout. If I want a better collet then I want a better design as well.

 

[wmpy]

One piece! The ball nuts are great, until contaminated. Plus they are fatter/taller which I find a detraction. A little oil on the nut taper helps when assembling, and I always use a torque wrench to tighten the screws or nuts. How else do you know if the torque is correct or even consistent?

Do you have a recommendation on a torque wrench for ER nuts?

 

[DavidScott]

Do you have a recommendation on a torque wrench for ER nuts?

Different sources have different specs, but mine for a 20 is max of 60 ftlbs. If the tool is small or the collet is hollowed out in the bottom, the shaft is not supported through the full length of the collet, then drop that to a max of 40ish ftlbs.

 

[wmpy]

Different sources have different specs, but mine for a 20 is max of 60 ftlbs. If the tool is small or the collet is hollowed out in the bottom, the shaft is not supported through the full length of the collet, then drop that to a max of 40ish ftlbs.

Thanks. 60 ft lbs is what I found in the REGO-FIX catalog for ER20 above 7 mm diameter.
I was actually asking for a recommendation on what wrench to get, though. Or can you buy a "socket" for the collet nut? As I'm typing this, I'm realizing that some collet nuts are just hex on the outside, so a deep hex socket would work. The one in this case is notched on the outside for a spanner, so I guess I need to look to see if anyone makes an adapter.

 

[DavidScott]

All my nuts are hex so I just use sockets. Take a look at the wrench that MariTool has with replaceable heads. If I didn't already have a wrench it would probably be the one I would get for its versatility.