Dreaming of a power draw bar

[DPittman]

Well I seem to have to dream and pontificate about a project for ever before anything happens, so I start that part of the process pretty early so the actual project might have a chance of materializing.

I am eventually going to get a riser block made for my 6x26 milling machine but that means I am also going to have to have a power draw bar in place as I already have the machine up pretty high.
I think I want to do something very similar to the power draw bar that @John Conroy has done and the one seen on Tom's Techniques YouTube.

I'm not familiar with Bridgeport style machines but on my little mill the impact setup has to sit on top of the belt cover and be able to flip open to change belts and occasionally change the drawbar itself out for a metric threaded one.

Just looking for some basic tips and advice from those that have made one and might make some changes to their own design now that they have run it for awhile.

 

[YYCHM]

Post and image or two of the top if the machine so that we can see what you're up against.

I to dither about projects, should I do it this way, or, should I do it that way, to the point where I end up saying just do something then it's started.

 

[kevin.decelles]

I picked up a butterfly impact on impulse last week..... I have the same dream [mention]DPittman [/mention]


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[YYCHM]

How often do you change belts? I haven't change a belt since I installed my VFD.

 

[DPittman]

I picked up a butterfly impact on impulse last week..... I have the same dream [mention]DPittman [/mention]


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Yup Princess Auto has one on sale ((right now or soon) and that has again started the long project process...

 

[DPittman]

How often do you change belts? I haven't change a belt since I installed my VFD.

Not often either but I would like to have the option of doing so without having to remove the power mechanism to do so (at the very least to change draw bars as that is something I do relatively often).

 

[YYCHM]

Not often either but I would like to have the option of doing so without having to remove the power mechanism to do so (at the very least to change draw bars as that is something I do relatively often).

Can you get at your draw bar without opening the belt cover? I can't.

 

[DPittman]

Can you get at your draw bar without opening the belt cover? I can't.

No sorry I wasn't clear. No I can not get at drawbar or belts with out flipping open the cover that the power drawbar mechanism would have to attach to.

 

[Tom Kitta]

Oh, I used butterfly wrench. System works OK, not great. I mean it does its job but is a bit "non professional". Main issue is that my BP clone is huge as its like a clone of series 2 and the butterfly is like 7ft over the ground. It would work far better for this size machine if it was a button based system - i.e. I press a button much lower, it removes DB, press it again and it puts it back in.

I used PA butterfly - the weaker one, not the PRO series. the weaker one is 75 lbs

Even with this hilly billy setup it is way faster then doing it by hand. I can post some pics.

 

[Janger]

https://canadianhobbymetalworkers.com/threads/r8-collet-set-or-r8-er32-collet-set.2406/post-29324

red neck or hill billy power draw bar. it just works. no project. get back to milling.

 

[Janger]

And for you guys with the tall mills:
https://www.canadiantire.ca/en/pdp/maison-kleen-folding-step-stool-white-1424388p.html#srp

 

[trlvn]

I don't know if it would apply to the mill you have but Mark Presling created a power drawbar system for his Bridgeport. There is a series of videos on the build:

Craig

 

[historicalarms]

No sorry I wasn't clear. No I can not get at drawbar or belts with out flipping open the cover that the power drawbar mechanism would have to attach to.

I removed the cover on mine 20 yrs ago and it has never been back on, those exposed belts are way above any danger area. I keep the cover beside the machine just so's I can read the speed charts periodically.

 

[Mcgyver]

I to pine for a PDB....but I probably only turn the air on 10 or 20% of the time I'm in the shop. Waiting for to cycle up, the noise and so on makes (for me) the ultimate power draw bar one that doesn't use air. I haven't seen an electric impact gun that would lend itself to this application so I keep hoping one of you smarter guys comes up with an idea

 

[DPittman]

I to pine for a PDB....but I probably only turn the air on 10 or 20% of the time I'm in the shop. Waiting for to cycle up, the noise and so on makes (for me) the ultimate power draw bar one that doesn't use air. I haven't seen an electric impact gun that would lend itself to this application so I keep hoping one of you smarter guys comes up with an idea

You know I share those same thoughts. I hate my noisy air compressor but I have an air blast oiler spray mechanism that I think I will occasionally use and that needs air at the mill anyhow. I too was hoping someone had devised a rechargeable electric version of the power drawbarbut I don't think I'm the one to bring it to fruition.

 

[Janger]

I'm telling you guys the portable power impact driver works great. No air. It sounds and looks like a joke but it's fast and simple. try it!

 

[DPittman]

I'm telling you guys the portable power impact driver works great. No air. It sounds and looks like a joke but it's fast and simple. try it!

I don't doubt that at all and the only reason I'm not doing the same is because the stretch and height difference between the top of my mill and the spindle. It would be a tough stretch to the power with one hand while holding the collet with the other.

Edit...maybe I should try and not dismiss until then!!!

Ps. My email notifications seem to have started again

 

[PeterT]

I'm telling you guys the portable power impact driver works great. No air. It sounds and looks like a joke but it's fast and simple. try it!

I use a cordless wrench with a socket, but its also within within my tippee-toe reach. My mill has a brake so I hold that when tightening/loosening. The wrench lever is quite sensitive so you can feel the torque. I never drive it home. I've wondered about a permanent electric version by gutting an e-wrench, hook up DC power, remote switch etc. But still have to solve how to disengage during long stretches of mill running, either mechanically or electrically. Also sometimes my drawbar still needs a light tap to disengage the quill seat even with drawbar unthreaded. Nobody seems to talks about a hung up tool after drawbar disengagement on the pneumatic systems. Maybe higher frequency pneumatic ratchet action imparts just enough shake?

 

[jcdammeyer]

Mine is progressing slowly. I 3D printed all the parts to test the theories. The blue tab on the RH post holds a hall effect sensor and there's a magnet on the socket. The idea is that I don't want to unwind the draw bar too far for the TT holders since they only need about 1 to 1.5 turns to loosen enough to be removed without the entire R8 part falling out.

For tightening max 3 turns or X seconds. I have a Load and Unload button and if they are tapped the behaviour is as above. If they are held then the draw bar runs for longer or until released. So it can still drop out the R8 TT Collet Holder or pull it or some other R8 tooling all the way up. The controller runs a couple of pneumatic valves to separately move the assembly down and separately engage the butterfly impact wrench. I found when I tee'd them together the way they were done in the plans I bought that the impact wrench bled too much air away from the cylinder and so it wouldn't go down.

The small collar on the bottom right unfortunately snapped the other day while putting the castings together.

So I took the 3D printed drawing, exported to the CAM software and then spent lots of time milling the inside 5/8" hole starting with the 1/2" drilled hole and then the outside.

Oh and the module also talks to LinuxCNC via CAN bus and lights a couple of indicators on the AXIS display. At some point it will all be integrated as part of an automatic tool changer.

 

[John Conroy]

I'm telling you guys the portable power impact driver works great. No air. It sounds and looks like a joke but it's fast and simple. try it!

The reason I'm a fan of power draw bars is my old mill and the new one both have draw bars over 7 feet off the floor. That requires a 2 step stool for me as my butt is built too close to the ground. It only takes one slip off the stool to break some body part that will takes months to heal and I've had some close calls. It's a matter of convenience but also self preservation. It was a fun project on my old mill and I don't think the system on the new mill works any better than the one I built for the old one but it is prettier.