ER COLLECT CHUCK vs. STANDARD COLLETS vs. END MILL HOLDERS

[zruvalcaba]

Guys, just bought a Grizzly G0704...upgrading basically from the small HF mini-mill. Wanted something a little bigger, heavier but still somewhat introductory and relatively affordable. I've seen nothing but good reviews on this machine and for my needs and work space, it suits me fine.

Quick question, on my HF mini-mill I was using a set of standard R8 collets that when needed to be changed required inserting a locking bar, unscrewing the drawbar nut, unscrewing the drawbar, then "popping" off the collet by slightly tapping the side of the spindle with a rubber mallet until the collet gave. Kind of a pain to be perfectly honest. Not sure I want to go that route on this mill. I've seen the ER type collect chucks and collets online and thought that might be a good option as replacing the collets is a simple matter of using a spanner wrench to loosen and remove the collet from the chuck without ever having to remove the drawbar. What are you guys using to make tool swaps easier? Also, what size would I need if I did decide to go the collet chuck route? ER-32?

Sorry if these questions sound lame...I'm really learning all of this as I go.

Thanks!

 

[Primered Thunder]

I have an ER 32 collet holder in my older M head Bridgeport mill. It has the tee-tiny Morse taper #2 quill and the ER32 was about as big as I could go. I use it for drills and end mills both with very good success. I've even been known to put a tap in there on occasion.

There is a guy on eBay that sells import ER series collets in different sizes and surprisingly enough they are pretty decent quality. I have some Royal collets that I have collected in my "travels" but also have a complete set of the import collets. The hobby work I do in my backyard shop can't tell the difference in the quality of the collets ... especially in a 64 year old machine.

I really like NOT having to use the drawbar to change out tooling. I highly recommend it.

 

[A_Pmech]

Personally, I'd stick with the R8 collets and continue using the drawbar.

All you're going to do with a collet chuck is eat up more Z, which on your machine is already at a premium. A decent hand on a Bridgeport can change tools in less than 20 seconds manually, 30 seconds if a collet change is required. Less than 10 seconds with a power drawbar or just a few more seconds for a collet change.

If you have a welder, make yourself a "drawbar tool" or buy one. It's very simple; a soft face hammer on one side and a socket to fit your drawbar hex on the other with about a 12" handle. It will be much faster than swapping tools in a collet chuck secured in the spindle.

 

[pugs]

+1

My manual Lagun mill has a drawbar wrench that I made. Just a combo wrench with a piece of brass rod held to it (slot and setscrew). Loosen the draw bar half a turn, give the top of drawbar a tap to pop holder out then unscrew drawbar rest of way with fingers.

Only reason I can see to use Er collets in a R8 spindle is to keep a tool setup when doing mulitple parts as then changing out the holders the tool would still be same depth as the last time it was in.

 

[fredybender]

Depends on your milling operations mostly:
I strongly suggest the ER32, especially in small size drills / endmill, where run out is critical.
A 1/4" 2F endmill will feed at about 0.001" in steel: Run out at 0.0005" and you got one tooth working 150% load...50% above load limits...

ER collets have 2 opposite tapers to ensure concentricity. R8, have only one taper, and a cylindrical guide, that needs to have clearance to fit...

In all tooling needs, anything below 5/8, I suggest the use of ER collets.
As for the added Z, for small size drilling operation the trade off is a no brainer.
As for milling, it depends on the diameter of the endmill being used; smaller diameter endmills will have the diameter ratio / length "weak link" and make this also an easy choice.

my 0.02, but I only make a living selling tooling

 

[cnc-me]

Kurt power drawbar.

 

[isaac338]

Quick question, on my HF mini-mill I was using a set of standard R8 collets that when needed to be changed required inserting a locking bar, unscrewing the drawbar nut, unscrewing the drawbar, then "popping" off the collet by slightly tapping the side of the spindle with a rubber mallet until the collet gave.

I have no insight on collet chucks, but I'm not sure you're supposed to be hitting the spindle with the mallet - I was always taught to loosen the drawbar and then tap the drawbar to release the taper.

 

[trbomax]

I have no insight on collet chucks, but I'm not sure you're supposed to be hitting the spindle with the mallet - I was always taught to loosen the drawbar and then tap the drawbar to release the taper.

This^^^^

 

[zruvalcaba]

Yeah, like I said I'm learning as I go. The small HF mini mill's manual specifically says to tap the spindle slightly with a mallet to loosen and free the collet from the spindle. Whatever, I just follow directions. Good to know though...won't be doing it on my new machine!

 

[zruvalcaba]

Thanks for everyone's feedback. I think I've come to a decision to go with the ER32 collets and collet chuck. I'm going to go with the R8 ER32 Glacern collet chuck shown here: http://www.glacern.com/er_collet_chucks and probably this set of collets: http://www.ebay.com/itm/Spring-coll...7?pt=BI_Tool_Work_Holding&hash=item35bfbd9d9d They appear to be German imports but at that price....who knows.

 

[Regnar]

 

[zruvalcaba]

That's pretty slick.

 

[Kevin54]

I'd stick with the R8's if it were me. A Kurt makes it a lot easier, but once you get used to changing R8's manually, it becomes old hat and you really never think about it. When I was working, depending on what the job was, you may have to swap out collets or tooling from an R8, 50 times a day easily if not more. With a Kurt automatic drawbar, it really makes things easier, but the only thing I don't like about the Kurt, and it depends on how much pressure is set as far as air, sometimes an endmill can "****" out of the collet. But then that is also dependent on how big of bite you're taking.

 

[Regnar]

Here is the one I made for my Cnc Mini Mill.

Sent from my iPhone

 

[pugs]

I buy holders and collets from www.maritool.com Have always been pleased with the quality and fast shipping from him.

 

[zruvalcaba]

I buy holders and collets from www.maritool.com Have always been pleased with the quality and fast shipping from him.

Where are their products made? $300+ for an ER collet set is beginning to sound a lot more like US-made than Chinese.

 

[lilscorpion]

The secret is a powered drawbar. Worth every dollar. ER's are great too but only solve the tool retention problem. They don't come out of the machine any easier. Look into a powered draw bar. It takes me maybe a few seconds to change tools and I don't think about it anymore.

 

[pugs]

I thought most of Mari's stuff is made in US, he does have some imports. Just ask him, he is real good about responding to emails.