ER32 collet chuck criteria for milling

ericc

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Hi. I was thinking of using my old horIzontal mill to cut pockets with an end mill. This will require some sort of collet. Recently, I purchased a SYIC ER32 collet at a garage sale. It looks like a pretty good one. Would a Banggood 3mt to er32 chuck work for this application? Low speeds and east The reviews on YouTube look pretty bad. This site has some positive ones. Would the run out cause problems with a good collet in it? Or would it be better to build one's own?
 
Any runout in the holder would transfer to the collet and then to the tool bit. But a small amount of runout may not make much difference in the end use, depends on the final accuracy that you require.

One other thing to concider is that when using a MT collet holder for milling, you need to secure the holder with a draw bar. Side loading (milling) with a MT holder will cause it to work it's way out of the spindle if not secured.
 
Thanks, Jim. I have a flycutter and a Randy Richard style shop-made dovetail cutter with one triangular insert that both wouldn't mind a little runout (like 0.005), but how about a 1/2" HSS endmill?
 
0.005 runout is quite a bit, but the final accuracy of the part is what really counts. Normally if I need to cut a slot that is on size, I use the next size smaller endmill and step over to final size. But, with 0.005 runout only one flute of the endmill will be doing most of the work. I would want a bit less runout. For most applications 0.0005 runout would be acceptable.
 
Hi. I was thinking of using my old horIzontal mill to cut pockets with an end mill. This will require some sort of collet. Recently, I purchased a SYIC ER32 collet at a garage sale. It looks like a pretty good one. Would a Banggood 3mt to er32 chuck work for this application? Low speeds and east The reviews on YouTube look pretty bad. This site has some positive ones. Would the run out cause problems with a good collet in it? Or would it be better to build one's own?

Hi Eric,
I have and use a Banggood MT3 ER32 collet chuck in my mill for tool holding without any issue. The runout varies with the collet fitted, but thats down to the collets. I've found that the collets need a good cleaning and deburing before putting into service. All the ones that I commonly use are in 0.0001" range.
 
Hi BaronJ. That is pretty good accuracy that you experienced. Much better than what I gleaned from web searching. So, if I have a decent collet, it should be OK to get the lower quality chuck. I noticed that most of the Ebay sellers for this item are in China and have mediocre feedback. After seeing that monster thread on the "too good to be true" chuck scam, this looks kind of scary, especially if the seller's location is Chino(China).
 
For things that need accuracy like collets and chucks, it seems to be a bit "luck of the draw". I have and use Banggood insert holders, they work fine. But I've seen reviews all over the place for collets etc.. Some get good results, others don't. I suspect it's just poor QA. For a more mid-priced option I've had good luck with Shars. The lathe ER40 chuck and the R8-ER40 were quite good indicated against the taper. Not as cheap as direct from China, but they seem to have a better reputation for QA and the limited times I've purchased they have met the spec they published.
 
Hi BaronJ. That is pretty good accuracy that you experienced. Much better than what I gleaned from web searching. So, if I have a decent collet, it should be OK to get the lower quality chuck. I noticed that most of the Ebay sellers for this item are in China and have mediocre feedback. After seeing that monster thread on the "too good to be true" chuck scam, this looks kind of scary, especially if the seller's location is Chino(China).

Hi Eric,

Using a 0.0001" test indicator I only see noise when reading inside the taper on the collet chuck. That noise is caused by stickiness of the stylus rubbing. Using a 12 mm slot drill in a collet, I might see 0.0003" or 4, and that will change simply by loosening the collet and rotating it a little.
I point that I did forget in my previous post, was use a ball bearing nut ! It makes it much easier to tighten up, as does a spot of oil in the nut.

Unfortunately all collets are not made equal, I've thrown a couple in the bin because I couldn't clean the harrage out from between the slits on the inside edges. I've also had one that had the two opposite slits missing !
And been told that it cannot happen ! Yea, "see those flying pigs".

I wish I'd kept it and taken some pictures of it, however Banggood sent me a new one, so no loss there.
 
ericc, ER-32 chucks of high quality in an MT3 mount are rare. Lots of Chinese stuff out there but you sort of have to wonder how good a chuck is when it costs less than $30.00 for the chuck and nut included. You can't even buy a good nut retail for that amount.

The reason I raise that point is because it is well accepted that for every 0.0001" of runout you have, tool life decreases by 10%. This is because one tooth of an end mill is cutting more than the others as Jim said. If you have a chuck/collet/nut combination that has 0.0005" TIR then your tool life expectancy will be dismal.

So, what to do? If I was in your shoes I would buy a chuck from a seller that publishes specifications online. Then I would check that chuck's taper to see if the concentricity of the chuck falls within those specs. If it doesn't then you can send it back but if there are no specs then you have nothing to stand on. Say you buy one from Shars (claims 0.0002" TIR) and find it to be okay. Then you need to decide on a nut and collet set.

The nut can make a huge difference in the runout of the assembly. Cheap nuts can have or cause double or triple the runout of a high quality nut. Good nuts come from ETM, Rego-Fix and Techniks. Rego-Fix and Techniks both sell hard coated as well as ball bearing nuts. The Chinese ball bearing nuts are junk, at least in my experience.

The collets you use also make a big difference in runout. Rego-Fix, the originator of the ER system, is probably the world standard but ETM is also very good. The best ER collets for the money probably come from Techniks. Their collets are made in Taiwan and are some of the best collets you can buy at their price level. Centaur also makes some good collets but are pricier. Lyndex is also well known but Techniks specs are better.

Whatever you decide to get, consider spending some money and get good collets if you can find a good chuck and nut. That will give you the best chance at decent performance and tool life.
 
Hi Mikey

The reason I raise that point is because it is well accepted that for every 0.0001" of runout you have, tool life decreases by 10%. This is because one tooth of an end mill is cutting more than the others as Jim said. If you have a chuck/collet/nut combination that has 0.0005" TIR then your tool life expectancy will be dismal.

What a load of rot ! Most cannot even measure a tenth of a thou !
 
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