Collet information

[millipedeman123]

Ive got a 1980 3HP Lagun FTV1 mill with an R8 spindle. I was wondering if an Er32 or ER40 collet adaptor would be acceptable. This is full size machine much more ridgid and beefy than BP while retaining the same layout and controls. Ive had 2 SLAP tears repaired with one needed additional surgery with some cysts and other issues in my shoulder making heavy lifting and overhead reaching difficult for me aka reaching the drawbar. Would ER40 collets be accpetable as they have the greater range of things I could grab and tooling available without having to reach the drawbar. My machine has a very nice brake that can lock very easily so holding the spindle isnt a problem. What would your take be as this seems a simple and economical way to make my machine much easier to use.

[John Evans]

That is one way or fit it with a power drawbar. If you have a fair bit of R-8 shanked tools the power drawbar may be your best bet.

[SteveM]

As with everything, there are tradeoffs.

The ER collet chuck will add overhang, so you will loose some of that rigidity that you have.

An ER doesn't have the locking setscrew that a weldon shank end mill holder has, so you may risk having an end mill pull out on you,

All that said, I have a Bridgeport M-head with a B&S7 taper spindle, and I bought a B&S7 to ER32 collet chuck, because finding B&S7 tooling is harder than something like R8 or MT2/3.


Steve

[millipedeman123]

I dont have much r8 tooling Boring bar set collets and drill chuck adaptor. a power drawbar is about 200 more than a er40 collet set but might be worth it R8 tooling seems fairly reasonably priced most places

[shootnride]

Personally, I would opt for the power draw bar. If you don't like the prices for the commercially available ones, you can make your own. I have a Kurt power draw bar on my BP mill, and it really is a very simple device, much like the shop made one in the link below. There are many examples of home made units on the internet.

http://www.the-alchemist.com/powerdrawbar.html

Ted

[BadDog]

I'm with John. Power draw bar is a great option that gets the R8 set right every time (once setup), and ejects effortlessly, both almost immediately. I want one, but just too cheap and haven't had time or option to build one. Also, R8 tooling is by far the most common and cheap. And the straight shank stuff you could use in an ER, you can also grip in the R8 collets, as long as it's on-size for the collet set you chose (R8 not being an "ER" collet).

ER32 collets take WAY more torque to tighten properly than most people think. You generally need a longer lever than the provided wrench provides, and even then it's still quite a bit of torque (look it up). And then when you are forced to the next biggest size because what you need to hold is just a bit too big for the closest size, when you run it down to take up all that extra gap, you are going to be cranking for a while with every increment under load, and done in a semi-awkward position while trying to hold the part in place if done while in the machine (as it seems your's would be). Neither sounds ideal for someone with arm issues.

[pete]

Russ is correct about that proper closing torque required on the ER collets. And I suspect why some have issues with a tool moving on them. ER-40 is about 120 ft. lbs for tool holding if I remember correctly, and unless your a weight lifter the supplied wrenches are too short. It's a good system and if I want a real rigid and accurate method of holding drills I'll use my 40's instead of even a real good drill chuck. With your overhead reach issues I'd seriously consider those power draw bar systems already mentioned. The R8 collets are of course more rigid but can't fit sizes other than the one it was made for. The ER's can give you some added reach if it's needed sometimes and the collet chuck and nut can get in the way sometimes as well. I still think the proper R8 collets are the better way most of the time.
I bought my ER's so I could get dual use out of them by holding work in the lathe as well as tooling on the mill. The closing torque then is a lot less since the clamping force needed to resist the part moving is a lot less severe. 5C is a better collet system for part holding so my use of the ER's is still a compromise.

None of them are cheap and they make any current R8 shanked tooling dust collectors. But there's also the R8 quick change designs around that make tooling changes pretty fast and easy. I'd love to have one of them until I add up what I have just in R8 shanks alone and then add up how much I'd have to spend converting to whatever shank size the quick change systems use.