Confused About Collets, Spindle Taper

grepper

grepper

Registered
Registered
Joined
Jan 8, 2016
Messages
171
Sorry for the utterly noob question, but I can’t seem to Google my way out of it. So, I’m getting ready to purchase my first mill, but suddenly I don’t understand…

The HF mini mill has a R8 spindle taper. The LMS has an ER16.

What exactly is spindle taper? What does it mean? Does it dictate the type of collet used? Is it like the jam fit MT for drill chucks/shanks?

I was thinking you put different size collets into some sort of a holder, or chuck to accommodate different shank sizes of end mills or drills. Is this correct? Is the spindle taper simply the taper of the shank that holds the chuck that holds collets?

As you can see, I’m totally clueless and lost.., hopelessly lost. I feel like an idiot! Can anyone please help me get a really basic understanding? My head hurts from Google.
 
Its just a holding system for your toolholders . R8 is the industry standard and is readily available . Cheap too . Hope this helps . There are NO DUMB QUESTIONS ! ( sorry for the yelling )
 
Thanks. I found this video.


I think I get it. Collets or other tool holders like a chuck, slide directly into the spindle of the mill. The taper of the spindle dictates the type of collet or holder used in that the taper of the collet or tool holder much match that of the spindle. Correct?

So, which is best for a mini mill? R8 or ER16? Why is HF R8 and the more expensive LMS ER16? Why would LMS choose ER16 over R8?
 
Last edited:
Yes to your question .
IMO ..............Don't buy anything other than an R8 . I'm an oldtimer though , so do your research .
 
My head hurts from hours and hours of research. It's a hair pulling freak show!

I truly respect "old timer" advice. Usually it's the best.

So why would LMS choose ER16 over R8 on their more expensive high torque mills?
 
The R8 collet system was originally developed by Bridgeport and has commonly been accepted as a tool holding system in small mills. To maintain concentricity, the collet has a cylindrical section at the top and a tapered section at the bottom. A threaded drawbar pulls the tapered section into a mating socket to grasp a tool n the case of a collet or to provide for registration with the spindle axis. R8 adapters are available with different tapers to mount chucks or threaded sections for mounting boring heads. R8 collets can accommodate tool shanks up to 1" in diameter.

ER16 Collets have a taper on either end of the collet which provides for better registration with tools that smaller than the nominal collet size. An ER collet cannot accept a tool shank larger than 13/32" so tool sizes are limited. While it is possible to make an straight shank adapter for a drill chuck, you would be limited to a 3/8" shank. due to the extension of the ER16 collet system beyond the spindle, there will be a loss of rigidity as well.

The bottom line: IMO, the R8 system will give you more versatility and better rigidity than an ER16 system.
 
Thumbs up to what he ^ said !!! Now my head is spinning !! LOL !

If you stall such a mill , you have other addressable problems . A 1 hp j-head mill is capable of any job with the correct tooling .
 
Thanks guys! Seems everybody, including Jim, agrees R8 is the way to go.

Thats interesting. Only the most expensive $1500 LMS mill has a R8 the rest have ER16. But the HF, $530 (with the endless 20% coupon required), has an R8! But the LMS has an air spring and belt drive while the HF has cheapo plastic gears that break, no belt drive, no air spring and must be upgraded. :rolleyes:

Why must life be like this?

Thanks for the help everybody!
 
Because , in my bestest singing voice . " That's the way it is " .

Be on the lookout for a BP or similar knee mill . If you plan on spending that kind of $$$$$ , it would be a wiser investment . IMO .
 
You must log in or register to reply here.
Back
Top