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MT 4 tool holder and options

WilliamR

Active Member
Started back on getting the mill/drill going and found out spindle was MT 4B, not R8 as advertised. Maybe just the places I've been searching, but MT4 doesn't seem as popular as MT 3 let alone R8 or the CAT stuff? Seeing a lot of clearance sales on MT 3, is it being phased out as well?

Is getting an MT 4 to MT 3 adapter and using MT 3 stuff a good idea or should I try and stay with MT 4?

R8 spindle was an option on this RF 45 clone, I guess conversion would be $$$, but would I be better off in the long run?

Searched 6 pages of "morse taper" results but not much came up on MT 4.

Any thoughts/ideas appreciated.
 

DavidR8

Scrap maker
Administrator
Moderator
Premium Member
Started back on getting the mill/drill going and found out spindle was MT 4B, not R8 as advertised. Maybe just the places I've been searching, but MT4 doesn't seem as popular as MT 3 let alone R8 or the CAT stuff? Seeing a lot of clearance sales on MT 3, is it being phased out as well?

Is getting an MT 4 to MT 3 adapter and using MT 3 stuff a good idea or should I try and stay with MT 4?

R8 spindle was an option on this RF 45 clone, I guess conversion would be $$$, but would I be better off in the long run?

Searched 6 pages of "morse taper" results but not much came up on MT 4.

Any thoughts/ideas appreciated.
My experience has been that when using an adapter tolerances start adding up to perhaps intolerable levels. :)
My mill had an MT3 taper and I exclusively used TTS tool holders with 3/4" shanks chucked into an MT3 collet. I did start off with an ER32 collet chuck on an MT3 taper which was good but I found the extra stickout was challenging.
 

Tom Kitta

Ultra Member
Just get MT4 to ER32 chuck from aliexpress. Cheap, Available and you can get it with a threaded end in metric thread.

Lots of MT options - if you had something exotic, like MT4.5 or some B & S spindle than I would worry. But MT? It is common. Most Mill drills come with MT.

MT4 is going to be more rigid than MT3 in MT4 adapter. Also how would you pull the MT3 into the MT4? Would you use a draw bar that connects to MT3 and goes through larger thread on MT4? For drilling there is no need for a draw bar but for milling you need a draw bar.
 

WilliamR

Active Member
My experience has been that when using an adapter tolerances start adding up to perhaps intolerable levels. :)
My mill had an MT3 taper and I exclusively used TTS tool holders with 3/4" shanks chucked into an MT3 collet. I did start off with an ER32 collet chuck on an MT3 taper which was good but I found the extra stickout was challenging.
Just get MT4 to ER32 chuck from aliexpress. Cheap, Available and you can get it with a threaded end in metric thread.

Lots of MT options - if you had something exotic, like MT4.5 or some B & S spindle than I would worry. But MT? It is common. Most Mill drills come with MT.

MT4 is going to be more rigid than MT3 in MT4 adapter. Also how would you pull the MT3 into the MT4? Would you use a draw bar that connects to MT3 and goes through larger thread on MT4? For drilling there is no need for a draw bar but for milling you need a draw bar.
@David_R8 Thanks I wondered if using adapters (especially $20 ones) might cause problems with wobble or turning in taper etc. They are out there, thought it might be a common fix. Seems more selection local with MT 3.

Was thinking maybe ER 40, I'm sure 32 would work for me just as well. I saw TTS stuff out there, wasn't sure what it was all about. Will look into it. Thanks.

@Tom Kitta Thanks, haven't shopped at aliexpress before, was looking at the local importers, kms, kar, accusize, amazon.ca, busy b etc. Coming from China it probably would have same M16 threads as my current drawbar.

I think the adapter is similar to what you describe, slip in MT 4 then MT 3 drawbolt to tighten tool holder.
71AmW8+IDQL._SL1500_.jpg
 

WilliamR

Active Member
Thanks. Was going to order mt4 from Aliexpress but so many choices/different prices. I wonder if the no name $370 kit sold on Amazon.ca is same as $120 kit sold in China but with large profit margin...

KMS had MT3 er40 set on sale if anyone was interested
 

kstrauss

Well-Known Member
Was thinking maybe ER 40, I'm sure 32 would work for me just as well. I saw TTS stuff out there, wasn't sure what it was all about. Will look into it. Thanks.
TTS stands for Tormach Tooling System. It is based on holders having a short 3/4-inch shank with a 1.38-inch diameter section that registers against the bottom of the mill spindle. It allows you to have a reproducible stickout for each tool. Very useful for CNC but probably irrelevant for most work in a manual mill.
 
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