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Power Drawbar

slow-poke

slow-poke

Ultra Member
I'm starting to think about making a power drawbar for the A1S mill.

How many of you are using a power drawbar?

I'm not crazy about the air ratcheting approach seems like it would be annoyingly loud, would prefer electric .

Comments please and If made one, pictures and details please.
 
I don't have a power drawbar but two things come to mind:

1 - if you're in a production environment, time is money so a power drawbar would speed up changes.
2 - if the mill is 7 or 8 foot tall and requires a ladder to get to the drawbar then that would be a plus.

The drawbar on my previous mill (same as yours) and the Sharp I have now is at about the same height as yours so I haven't found a need/wanna to power the drawbar and there are no timelines or money for what I do.

I guess this goes back to wanna vs need and what is acceptable for you. Good luck.
 
Keep us posted. I always wanted to make one using a 120v electric impact vs the standard butterfly air impact ones. I don't always run my compressor when I'm using the machines, so don't want to have to pump it up just to change tools. Maybe one day I'll get around to actually designing something and building it.
 
I use an air ratchet on my bench mill. Mainly because my compressor is almost always charged so air is readily available. The biggest reason I use a ratchet is the drawbar threads extend into the tooling about an inch so the ratchet spins it out quickly.
 
I just checked my 18v makita 1/4" hex impact and it was almost perfect for the job. I didn't put a torque wrench on it, but it was almost a bit too tight compared to how much I tighten with a wrench, but not excessive. A few less ugga duggas on the trigger and it would be fine. I'd rather have a plug in 120v, but it wouldn't bother me having to swap batteries every once in a while as I've always got some charging in the rotation.

I have 2 extra impacts that have trigger and other issues I could probably use to make one good one for a build
 
Dan Dubeau said:
I just checked my 18v makita 1/4" hex impact and it was almost perfect for the job. I didn't put a torque wrench on it, but it was almost a bit too tight compared to how much I tighten with a wrench, but not excessive. A few less ugga duggas on the trigger and it would be fine. I'd rather have a plug in 120v, but it wouldn't bother me having to swap batteries every once in a while as I've always got some charging in the rotation.

I have 2 extra impacts that have trigger and other issues I could probably use to make one good one for a build
Click to expand...
Dan,
A small impact reconfigured might be suitable. I'm curious can you measure the torque produced by that impact. I need to determine a suitable drawbar torque as a starting place. When I tighten I always question myself is that tight enough or too tight?
 
On my 40 NMTB I don’t tighten the drawbar very much. 10-15 pounds max. When removing I need to give the tool holder a couple good whacks with a rawhide hammer. I clean every time I put one in though.
Not sure about an R-8 taper.
On my PDQ tooling, the wrench is about 36” long so it gets lots of torque when I install a tool.:rolleyes:
Martin
 
My Tormach CNC has a pneumatic drawbar. The R8 collet is gripped using a stack of Bellville washers so it is tightened consistently. Operation is almost silent. Certainly none of the racket of an impact wrench! It does require 125 psi air though.

I've seen other examples that use a DC gearhead motor to tighten the drawbar. They sense the motor current to determine how hard the drawbar is being torqued.
 
slow-poke said:
Dan,
A small impact reconfigured might be suitable. I'm curious can you measure the torque produced by that impact. I need to determine a suitable drawbar torque as a starting place. When I tighten I always question myself is that tight enough or too tight?
Click to expand...
I will try and put a torque wrench on it this week as I'm curious too. Was in too much of a rush today before heading out to the golf course to play around with it.
 
Here's my thread on project #42.
canadianhobbymetalworkers.com

Micro-controller controlled Pneumatic Power Draw Bar

This is a more appropriate place to continue the thread that started out asking about coil springs. https://canadianhobbymetalworkers.com/threads/coil-springs.3876/page-2#post-51519 Finally got around to casting the patterns today. Also since it appears that my AliExpress ordered pneumatic...
canadianhobbymetalworkers.com canadianhobbymetalworkers.com
 
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