NMTB 30 versus NMTB 40 Tooling

[MrWild]

My first junker mill had NMTB 30 tooling so I gleaned it when that mill hit the road. This was good as my second mill (A Supermax YCM-40) also had NMTB 30 tooling. My mill head (YCM-40) was giving me problems with speed changes and the brake, so when an entire head assembly became available at what I thought was a fair price, I grabbed it. It had a 72 volt SEM servo motor on the left side, while mine has 140 volt SEM on the right. As I was tearing into it for the pulleys and belt, I yanked the tool that was still inside it (Nice Erikson DA180 collet holder and 5/8 collet), and found it has a NMTB 40 quill.

My question regards the two different quills. Is it worthwhile to upgrade the entire quill on mine using the NMTB 40 quill and and also selling off my tooling to upgrade to NMTB 40, or not? The NMTB 40 tooling looks a LOT more substantial. Is this something that lowers the RPMs at all? Both speed adjustment dials sport the same speed ranges so I'm doubting this, but thought I should ask.

Maybe I should just swap the entire head assembly and just switch out the servo motors. I'd have to put the new head all back together, but it is amlazingly simple in how it is built.

Thanks!

[keebler303]

Its just a beefier taper. Its made for bigger, beefier machines with more power. It may be a nice upgrade but its probably overkill and It would be a real pain to swap all your tool holders for the larger variety. I'd keep the same taper and sell the NMTB 40 on ebay.

Matt

[DareBee]

40 taper is bigger, stronger, more rigid. less vibration, etc.
Tooling is also more common and readily available.
30 taper is no good for me. Obviously it works (has worked) for you.
If your tooling and work is not above the capability of the 30 taper then you have to decide, it depends on what YOU NEED.

[Dirky]

Due to the fact that I am a poor slob....I often have to go with the taper that comes in the machine I can afford.....so this has resulted in my having 4 types of tapers ranging from B&s 7....thats fun to buy tooling for ...on up to nmtb40......without a doubt the 40 is the toughest ...and good tools can be had for peanuts....the 30 taper works well for higher speed lighter cut duties...but tooling is rare and expensive by comparison. I would have to say though...that the too most important factors should be.....what head has the least runout.....and how much 30 taper tooling do you have now. The 30 taper will sell easily...and the 40 tooling is cheaper to buy......My buddies are always going on about chatter with the smaller taper.....but it most often is simply due to the fact that they want to push the machine to cut as though it is a 40 or even a 50 taper...its all relative to material...speed and patience...or lack there of....my thoughts......unless you have serious amounts of one type tooling or another...go with the head that is most accurate and run it as it was intended.....lets us know what you decide....Im always lookin for nmtb 30 stuff

[Dirky]

Hey...I just had another thought....shocking I know.....I may be interested in buying whatever head you Dont go with......maybe I could swap out that God-awfull B&s head.....never have been able to find much tooling for it anyway.....