What is the normal amount of force required to dismount an MT2 arbor without drawbar ?

C

compact8

Registered
Registered
Joined
Oct 13, 2012
Messages
350
I have two kinds of MT2 arbor2, drawbars type and tang type. The spindle of my hobby mill ( EMCO FB2 ) does not have anything to accomodate the flat tip of the tang type but just the drawbar. I have taken great care not to over tighten the drawbar when mounting the arbors but still the force required to dismount the drawbar type is a lot higher ( at least ten times I would say ). The tang-type arbors have never come lose during use but the force needed to seperate them from the spindle is worryingly low. That makes me wonder if this is normal. Sorry that I don't have any means to measure the torque needed but will appreciate if someone can shed some light on it base on feeling.
 
Last edited:
This can get complicated in ways that might have the answer be very variable.
The straight-pull force would depend surely on on how tight it was drawn in the first place, but a simple low force tugging, along with a little tap with a plastic faced hammer seems to have my MT2 let go easily. Of course, I may be experiencing something related to the possibly of "less than magnificent" bearing surfaces up the (tailstock) quill.

The (great :) ) wine bottle cap analogy may mean "normal" for both of us might be signalling we need to check out the condition of the taper up there. I have a (cheap) MT2 reamer set. The "roughing" cutter has toothed flutes, and the "finishing" one has straight edge flutes. These are strictly hand tools for "cleaning up" existing MT2 internal tapers. I gently tried the finish one, feeling for the kind of contact, and peeping up there to see what it might be doing. At my stage, I can't be getting adventurous to the extent of attempting to re-cut a internal taper. Although easy enough in principle, my knowledge of taper turning directly on my machine bits is so far, strictly books and YouTube! (OK then - I mean I would have to work up the nerve! )

My spindle taper is MT3, but the spindle is hardened. I expect any shenanigans around "improving" anything up there would involve toolpost grinders, and so far, given that the MT shanks do stick, and don't seem to slip, I don't expect to be messing with them. That said, they do come apart with a tug from one hand, along with a modest shock-tap from the plastic hammer, and I would rate the whole thing as being in wine-bottle cap territory.

[Edit: Please do let us not establish a casual de-facto release force unit rated in wine-bottle caps-worth! ]
 
Last edited:
A proper taper will not allow the tool to be removed by pulling.
it will require a tap of a drawbar , or hard turn on a captured drawbar like on my Clausing 8520.

My drill press does not have a good taper, it will drop the chuck easily.
My lathe TS and my mill lock things in very well and cannot be pulled on their own. The tapers will release under side load and that's why the draw bar is necessary. It pulls it up and it makes sure its tight, and it does not let the side forces loosen it.
 
I have had to add an extension bolt or pin to tangless holders for the tailstock on my lathe. It is basically impossible for me to pull out an MT3 tool…I have had to remove the quill and use a tapered punch through the slot provided in the quill. I found some tool holders are threaded on the small end, so it’s easy to run a bolt in and shape the head to match the tang. Some are not, for them drilling and tapping was straightforward. Tools that don’t need much torque resistance like a live center don’t really need a tang, just a pin.
 
Tang-type tooling as a rule is never used on milling machines.
Be glad your arbor is hard to remove, it indicates a good fit :)
A little light oil will help
 
I keep a rubber mallet around for when the drawbar needs a tap to release the mandrel.
 
You must log in or register to reply here.
Back
Top