Homemade power drawbar

[bigvinney]

After several months of using my first mill, I decided that tool changes are taking way to long, so I decided a power drawbar should speed things up a little. Here is my own version of the power drawbar. I got some ideas from others on this site and by looking at the ones you can purchase.

It is comprised of a plate with an impact wrench that slides on 5/8" linear shafts and an air cyclinder to push it down onto the drawbar. I dont have the airlines connected yet, Im still waiting for some fittings in the mail.

Let me know what you think.

Vince

[timlkallam]

Thats a nice one. Mine is alittle more simple I have to reach up and grab it pull it down . Its been on my mill for about 15 years .But it works great

[holbieone]

Originally Posted by bigvinney After several months of using my first mill, I decided that tool changes are taking way to long, so I decided a power drawbar should speed things up a little. Here is my own version of the power drawbar. I got some ideas from others on this site and by looking at the ones you can purchase. It is comprised of a plate with an impact wrench that slides on 5/8" linear shafts and an air cyclinder to push it down onto the drawbar. I dont have the airlines connected yet, Im still waiting for some fittings in the mail. Let me know what you think. Vince

nice work

[bigvinney]

I purchased the pillow block bearings and cylinder holder but machined everything else. It was actually the first time I have ever used a vise to hold parts, so I was just experimenting a little. It is actually very simple but looks complex. I cant wait for the air fittings to arrive so that I can try it out

Vince

[rasta]

Hi;
you may have a bit of a problem to let the taper unlock
unless you make a captive drawbar, also try to make a chanfer in the socket to allow it to fall readily into the drawbar hex, anyway it looks good
regards
rasta

[Servo Wizard]

Vince,

It's not often that I take the time to comment on some ones work but your's is exceptional. There have been a couple of suggestions offered so I'll add a couple of more; replace the shiney socket with an impact grade socket and valve the action so that it does not start until the socket is on the draw bar.

Way To Go BigVinney,

Servo

[wildcat]

Vince - very nice and VERY beefy looking. How do your controls look?

[bigvinney]

The socket is on there temporarily, I need to get an impact socket still. As far as valving the cylinder will go first and then the motor will spin. I have 2 mushroom button type valves for the air supply instead of using the one on the impact itself.

Also, what is a captive drawbar?

[bigvinney]

Here is a picture of the mill it is going on and also a picture of the air valves.

[HayreAss]

Originally Posted by Servo Wizard valve the action so that it does not start until the socket is on the draw bar.

Any suggestions on how to valve that way and still only have to press one button?

My only complaint with mine is that it spins up right away.

MY DRAWBAR

Yours is very nice my friend.
You spent a substantial amount of time and money on it, and it looks good.

One suggestion.
If you find it lacking balls due to back pressure in the air line like I did, save the hours of time and frustration I spent troubleshooting.

Quick exhaust air valves from McMaster-Carr (6646K31) solved my problem.

You can see them mounted on top of the wrench on some of my pics.

Brian

[bigvinney]

Exhaust valves are one of the items I am waiting to arrive. At first I didnt think about it but then I realized that because some of the check valves that I am using the cylinder would expand but then not release so I ordered some exhaust valves.

In terms of getting the cylinder to expand before the impact starts spinning, I changed how the air goes into the system. The incomming air goes through a "T" fitting but goes straight towards the air cylinder and the air has to make a 90 degree turn to go toward the impact gun. So hopefully this will give me a slight delay allowing the cylinder to activate first.

I am going to mount it and do some tests today, so I will let you know how it works.

Vince

[bigvinney]

Just finished mounting it to the machine and gave it a test run. It works great, the only thing that I may change would be to have a stronger air cylinder but it works fine with this one.

Also my idea of how to plumb the air lines works great as well, the cylinder expands then the impact starts to spin.

Here are a couple of pics of it on the machine.

Vince