Finished Powered Drawbar for my mill...

[BobWarfield]

Guys, if you don't have one of these, you should look into one. They are the greatest thing since sliced bread. Very easy to build, and mine works extremely well. I hate to sound like an advertisement, but I was just so tickled at how nice it is for no more trouble than it was to build!

Here are a couple pix of the finished result:





To operate, press the side of the lever marked "OUT" and the tool will drop into your hand in 2 or 3 seconds. Insert a new tool in the spindle, press "IN", and it torques it down again in another 2 or 3 seconds.

There is a little movie of it on my web page:

http://www.thewarfields.com/MT/CCMillDrawbar.html

This is based on Joe Vicar's plan set, which are cheap and worked out really well for me:

http://home.insightbb.com/~joevicar3/cheap_drawbar.htm

The impact wrench you'd need was on sale at Harbor Freight not long ago, but I don't know if they still are. This would be an easy project to get running between Xmas and New Year's.

Cheers,

BW

[Willbird]

I looked at the air butterfly at Harbor Freight, the tag said it was 75 ft lbs, but the actual box said 50 ft lbs. They show the one online that you have but not sure if they have them in stock or not.

Bill

[ZipSnipe]

Nice Bob!!! , Good work as always.

[wildcat]

Bob, did you need to make any modifications to the original plans other than the mounting plate? I don't recall the springs in the original plans...

[BobWarfield]

The springs are the only thing I changed. Your mileage may vary. I think it will depend on how strong the return spring is on the air cylinder as well as how smoothly things ride on the rods. On the web page I suggest that if someone sees a way to get those rods riding on some UHMW plastic, life would be good.

With that said, the springs are a trivial update. The plans are excellent.

Go for it!

Best,

BW

[Willbird]

Just looking at it it seems like if there was a way to get another guide plate onto those rods and the air butterfly it would work smoother. Even if it was made of nylon maybe ?? It would have to be clamped on and have the holes bored at assembly maybe due to the cast nature of the tool body. Hmmmm it could be bolted the the end of the Bimba maybe with some small flat head screws...I guess I need to make my own design and start collecting the $15 for plans myself ;-)

Wondering if a snap ring groove could be cut in the bores, and a split ring be made of the slippery plastic that would snap into the groove to provide a slikly smooth slide...the split would be large enough to allow it collapse enough to enter the bore, then it would spring open and be held captive in the groove.

Bill

[BobWarfield]

No question it could be done. Do keep in mind that the drawbar works well with the springs, which were dead easy to install. I think if you order a slightly larger air cylinder or perhaps a different brand, you'll find one that contains a stronger return spring and that would work too.

If I were building another, I might think about getting some UHMW in there, or getting a larger air cylinder, or I might just do exactly what I did. As I say, it works well.

Best,

BW

[l u k e]

I always wondered how these worked. I didn't know they implemented a impact wrench, that's pretty slick.

A few questions:

1. How do you manage to get a positive engagement of the air tool every time? It seems like it would be "hit and miss" getting the socket on the draw bar.


2. How does the tool release from the mill without a tap on the head of the bar? Does it just get forced out?

[BobWarfield]

Originally Posted by l u k e I always wondered how these worked. I didn't know they implemented a impact wrench, that's pretty slick. A few questions: 1. How do you manage to get a positive engagement of the air tool every time? It seems like it would be "hit and miss" getting the socket on the draw bar. 2. How does the tool release from the mill without a tap on the head of the bar? Does it just get forced out?

Luke, get yourself a copy of the plans and #1 will be clear.

As for #2, the pressure from the air cylinder holds the drawbar down while the screw forces the holder loose from the taper.

Works well.

BW

[l u k e]

Originally Posted by BobWarfield Luke, get yourself a copy of the plans and #1 will be clear.BW

Darn, I didn't know was the "million dollar question" (or in this case the $15 question )

I didn't really need plans for the design as I was going to approach it a little differently.

[bill south]

Good Work Bob!

I have the plans and most of the parts for the mounts. Most are drawn in Bobcad and code written. I just need to get off my lazy rear and put it together. BTW, good movie. Does the power of the impact really turn your machine on its side????
Bill

[Willbird]

http://tinyurl.com/ya5unv



There is the link to the patent that covers this device

Bill