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customcutter
11-14-2015, 12:06 PM
I ordered a cheap set (chinese) of ER40 collets. I managed to make a face plate, and mount a collet holder from a different Mfg. All in all I was able to get .0004" TIR, so I was pretty happy with that on a 1" Weldon 4 flute mill.

Now I'm trying to chuck up a piece of rod and was barely able to catch 2 or 3 threads with the nut on the collet holder on the face plate, (remember it's from a different Mfg). I mounted the MT-3 collet holder that came with the set in the tail stock, and tried to insert a 1/4" center drill and can't get the nut to thread back onto the collet holder. Same with any collet I place in the holder. I can press them in slightly, but then no luck chucking up the material if it's to size.

I'm wondering if the taper is slightly long or oversize, or is normal for the nuts to only catch a few threads? Or if there might be something I'm overlooking. Thanks in advance.

CC

1200rpm
11-14-2015, 12:07 PM
You have to snap the collet in the nut first

RichR
11-14-2015, 12:11 PM
I've never used ER collets, but aren't those the ones you have to hold the collet at a slight angle and snap them into the nut prior to
inserting them into the holder?

danlb
11-14-2015, 01:09 PM
ER collets are neat. I have some for each lathe.

A common problem is that the 1/4 inch collet will hold a rod with a MAX of 1/4 inch diameter. A .258 is a very tight fit.

The problem that goes along with this; cheap sets of "imperial" collets are sometimes the nearest metric equivalent and just marked as if they were inches.

I had some ER collets that were not well made. Even though they were ground well, the longitudinal cuts that provide the spring were not all cut the same. Some were cut shallow enough that the collet only compressed on one side.

Dan

danlb
11-14-2015, 01:10 PM
I've never used ER collets, but aren't those the ones you have to hold the collet at a slight angle and snap them into the nut prior to
inserting them into the holder?

Yes, they are. There is a groove around the top of the collet that the nut snaps onto.

Dan

customcutter
11-14-2015, 02:53 PM
You have to snap the collet in the nut first

Thanks everyone. As usual, it's the dummy behind the nut again. Not the inexpensive (chinese) parts. LOL

Georgineer
11-14-2015, 04:05 PM
Try this link:
http://www.rego-fix.com/fileadmin/user_upload/Bilder_Zeichnungen_PDF/home/Infos/Downloads/REGOFIX_EN_02_Collets2011.pdf
The assembly instructions are on page 2-4

George

Paul Alciatore
11-14-2015, 11:04 PM
As far as I know, ER collets are actually made in METRIC sizes in 1mm steps. When you see a set labeled in English (inch) measure, they are just trying to translate the actual, METRIC size to a usable English equivalent. But the translation is not exact. So, a 6mm collet may be labeled as 1/4" but it is not 1/4", it is 6mm and will hold diameters from 6mm DOWN to 5mm. 1/4" is actually 6.35mm and is too big for a 6mm ER collet. You need to step up to the next size or 7mm.

And, since they are in 1mm increments which is about 40 thousandths of an inch, some/most of the ER collets will cover at least two 64th inch sizes. Some will cover even cover three. The labeled sizes in mm are usually the upper or larger metric size that the collet will hold. But any fractional inch sizes that they may be marked or otherwise labeled as will not be the upper nor the lower end of the collet's range. It will be somewhere in the middle.

You need to make up a table of the actual English/inch sizes that each ER collet actually covers. I labeled the collet rack with them, along with the metric sizes.

kitno455
11-15-2015, 07:33 AM
You actually can get imperial sized ER collets, but from the big name makers, not the no-name Chinese ones.

allan

Puckdropper
11-15-2015, 09:25 AM
As far as I know, ER collets are actually made in METRIC sizes in 1mm steps. When you see a set labeled in English (inch) measure, they are just trying to translate the actual, METRIC size to a usable English equivalent. But the translation is not exact. So, a 6mm collet may be labeled as 1/4" but it is not 1/4", it is 6mm and will hold diameters from 6mm DOWN to 5mm. 1/4" is actually 6.35mm and is too big for a 6mm ER collet. You need to step up to the next size or 7mm.

And, since they are in 1mm increments which is about 40 thousandths of an inch, some/most of the ER collets will cover at least two 64th inch sizes. Some will cover even cover three. The labeled sizes in mm are usually the upper or larger metric size that the collet will hold. But any fractional inch sizes that they may be marked or otherwise labeled as will not be the upper nor the lower end of the collet's range. It will be somewhere in the middle.

You need to make up a table of the actual English/inch sizes that each ER collet actually covers. I labeled the collet rack with them, along with the metric sizes.

I've got some ER16 collets that are inch sized. Sometimes I get a piece that's not quite 1/4" that the 1/4" collet doesn't want to hold readily but the 6mm collet holds just fine.