Problem- NT 30 tool holders

[sharp-shooter]

I have a bridgeport R2E3 that uses NT 30 tool holders, and was wondering if it could be converted to use a drawbar system instead of the locking collar. The tool holders have a 1/2"-13 thread in the top. Is it possible to set this up for a power drawbar? Changing tools with a hammer and wrench is a pain.

[mactec54]

Hi sharp-shooter

The answer is yes
If you have a through hole in the spindle for the drawbar (as some don't) then just
build it, take a look at the Kurt Power Lock drawbar & there are some others as well
to give you an idea of what you need to do.

[creep_pea]

Hi

Unless your taking huge cuts or something the locking collar doesn't need to be tightened with a wrench and hammer!

I personally only tighten mine by hand but I'm usually only cutting aluminium.

Cheers

Chris

[sharp-shooter]

Mine has come loose twice just cutting wood at hi-speed with just a hand tighten. I tap it with a wrench just to make sure.
Did Bridgeport ever offer a drawbar as an option on this machine?

[sharp-shooter]

Weel, I guess this is a no-go.....the spindle does not have a through hole. Back to the wrench and hammer.

[John Bennett]

You might want to check the adjustment on the locking nut as with time and wear they do get out of adjustment. I have hogged out steel with just the nut tighten with the wrench with no problems.

[MrBoss8]

I don't think there is an adjustment, just new parts for the locking action on Boss QC (Erickson) spindles.

Have you adjusted one? If so how?

[vmax549]

Are you using erickson QC tool holders? The cheap generic Nmtb 30 holders do NOT have the proper headspacing to allow the lock collar to lock up tight.

USing the proper holder, hand tight is all you need to do heavy hogging.


(;-) TP

[MrBoss8]

That is absolutely right. The cheap generic holders can let the lockcollar move to its limit without, or with minimum preload. I had one of these fall out "twice" finish cutting .005 in aluminum with a 1-1/2" EM @ 1800 rpm. I couldn't believe it the first time, but I did the second.

[Dennis Storzek]

Originally Posted by MrBoss8 I don't think there is an adjustment, just new parts for the locking action on Boss QC (Erickson) spindles. Have you adjusted one? If so how?

Ditto on the admonition to use only Erickson brand tool holders. I run the spindle on my BOSS 6 up to 5k, only hand tighten with the short spanner provided, and have never dropped a tool.

Here's the adjustment instructions from my manual:

1. Remove three screws from locknut (the locking collar.)

2. Screw on nut assembly as far as possible – then back off one turn.

3. Insert standard Quick Change adapter and tighten locknut.

4. Screw in longest button head screw (dog point) in hole that permits greatest amount of rotation for unlocking. (This is usually the hole closest to a locking ear.)

5. Rotate nut back to load position. This is when the locking ears and keys are in line.

6. Insert cadmium plated screw in hole that is in line with locking ear. This is identifying screw so operator knows how to load adapters.

7. Put remaining screw in only open hole. Spindle is now ready to use.

Dennis

[MrBoss8]

Hello Dennis, what you refer to is the assembly procedure, if this is not followed the clamping collar will not work at all. It seems the cheap generic toolholder flanges check about .004 less than the Erickson toolholder flanges which are very consistent. Thats .004 from a good sturdy fitting toolholder, to one that is going to fall out.

I had to replace the parts in the spindle nut to restore new action. (generic still unusable)

I thought maybe you knew a method for tweaking that .004 range.

[sharp-shooter]

What I'm using is probably not considered "generic"...one is an Erickson, the rest are Carboloy, and as far as I can tell they are the same dimensions.
I talked to a machine builder, and he said the spindle can be drilled for a drawbar. I looked at my machine manual for removal of the spindle, and it sounds too easy, is it that easy to remove it?