Question about tool holding?

I use both end mill holders and collet holders in TTS. The collet holders, or R8 collets tend to have a bit less runout. This isn't that critical on larger end mills, where the runout is much less than the feed per tooth. When you get to smaller end mills, it does make a difference, because if the runout is as large or larger than your feed per tooth, then one side of your mill is doing all the work (and twice as much as you intended it to). I use the holders pretty much interchangeably down to 1/4", from there down I use the collet holders exclusively. As for pullout, I have had the TTS toolholder pull out of the TTS R8 collet, but I've never had and end mill pull out of an ER collet. There is a very good white paper on Tormach's website that details what needs to be done to get the maximum holding force from an R8 collet. It includes test data, and is an interesting read for using any collet system. As for the ER collets, they have to be tight. The recommended torque values on them are surprisingly high.

Here is the link to that paper:
http://www.tormach.com/document_direct_download.html?doc_id=163
 
I prefer ER collets & really like them. I rarely use R8 collets & never use them to hold endmills. Just my personal preference though.

valleyboy101 said:
My experience with ER40 collets is that with up to ~ 5/8" end mills and moderate cuts - no problem. However with larger mills and heavier cut the mill will be slowly pulled out of the collet. For that reason I don't use collets for larger end mills, instead I use a holder which secures the mill with a set screw.
Click to expand...

Ball bearing collet nuts would help remedy that. I use Lyndex BB nuts & love them now. ER collets can handle a lot of torque (the nut/clamping force), many do not realize that (myself included at first). For example, ER40 can be torqued up to 130 ft/lbs. That's a lot & most people probably don't tighten them close to that.
 
Just starting out, I would get yourself an R8 collet set. You can get a 12 pc. set such as http://www.grizzly.com/products/12-pc-Precision-R-8-Collet-Set/G1646 for fairly cheap.
Not a big cost investment, and you can never have too many tool holding methods. I mainly use Tormach w/ ER collets for for small critical stuff, and have solid end mill holders set up with common size mills that I keep handy to save time. I still like to keep a set of R8 collets kicking around for occasional use.
It will be the first set of many tool sets you will eventually have in your arsenal.

Pat
 
cjtoombs said:
I use both end mill holders and collet holders in TTS. The collet holders, or R8 collets tend to have a bit less runout. This isn't that critical on larger end mills, where the runout is much less than the feed per tooth. When you get to smaller end mills, it does make a difference, because if the runout is as large or larger than your feed per tooth, then one side of your mill is doing all the work (and twice as much as you intended it to). I use the holders pretty much interchangeably down to 1/4", from there down I use the collet holders exclusively. As for pullout, I have had the TTS toolholder pull out of the TTS R8 collet, but I've never had and end mill pull out of an ER collet. There is a very good white paper on Tormach's website that details what needs to be done to get the maximum holding force from an R8 collet. It includes test data, and is an interesting read for using any collet system. As for the ER collets, they have to be tight. The recommended torque values on them are surprisingly high.

Here is the link to that paper:
http://www.tormach.com/document_direct_download.html?doc_id=163
Click to expand...

Thank you for that link. I use MT3 collets in a shop-made chuck to it's highly relevant to me. Do you use anti-sieze on the outside of your collets? If so, what kind?

Interesting suggestion to put lapping compound on cutter shanks. I'd have to be desperate to do it, though. If the cutter *does* spin...
 
Being your so new it is safe to assume you have alot to buy. Dont get caught up in the best to max out the machine. You need bang for the buck at this point. What ever system will get you the furthest with out becoming useless later, is where you should be looking IMO. If you have a r-8 taper and they are gonna be the lowest cost option then buy that and a chuck. Unless you have correct change. Then buy it all. But I would rather have one way to hold a end mill and 10 set up, lay out, hold down tools then 10 ways to hold a tool and a c clamp.

Use your money to set up for as much as you can now and worry about optimizing set ups when you know what optimized is.
 
John,
I use a Loctite brand anti seize that comes in a stick, kind of like a giant lipstick tube. I think another thing you could do before you resort to lapping compound would be to sandblast the shank of the endmill, which would rough it up a little for more bite. I haven’t tried that yet myself, but I had heard it mentioned somewhere else and it seemed like a good idea.
 
A second thought ... If you are trying to get set up for as least cost as possible... You really only need a few collets. You can order just about any size end mill under 3/8" with a 3/8" shank, Under 1/2 with 1/2" shank and under 3/4" with a 3/4 shank. I have sets of collets, but the 4 that get used %99 of the time are 1/4,3/8, 1/2 and 3/4.
 
End Mill Holders -- You get a positive lock with the set screw.

"Billy G"
 
My last thoughts on this post....
I looked up the model machine ... only 2" of quil travel would be my deciding factor.
With end mill holders you will never be able to change cutters without moving the ram up then back down, removing the work piece or moving the table. With the r-8 collets you can slide the cutter out then remove the collet. This machine is not rigid enough to require end mill holders. The ER collet idea is not bad, but I think It will put extra stress on the spindle. If you go that route you need to take it a little easier.
 
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