Wow this looks good power drawbar

[Alistair Hosie]

This looks good for the money don't you think? I don't think you could make one cheaper time you costed in your work hours I don't have a bridgy I wonder if they could be adapted whatyou think ?Alistair






http://cgi.ebay.co.uk/Milling-Machin...lenotsupported

[John Stevenson]

To be honest Alistair it looks expensive to me because it's just a butterfly wrench on two spring loaded columns and you manually pull it into position then hit the switch.

Most of the other kits have pneumatic cylinders to engage the drawbar.

You can buy a butterfly wrench off Ebay in the Uk for £14 or £15 plus postage.

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[Alistair Hosie]

whats a butterfly wrench when it's at home sorry John you know me??Alistair ok I just looked one up I have one similar how about the lever controls ,and stand that makes a slight difference doesn't it?

[John Stevenson]

Ignore the bottom knob and the slotted plate, this is for a step speed bridgport mounting.

The top knob is connected to a vertical shaft that also connected to the bit of angle iron with In and OUT stuck on it.

To use you pull the whole assemble down with the top knob so the socket is sat on the drawbar then twist the knob so the angle iron presses on of the paddles on the front of the wrench and that will operate it.

It's because of the paddle operation that people use these wrenches hence the name butterfly wrench.

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[Highpower]

Basically the same thing as my Kurt manual drawbar. Only difference is - on the Kurt when you push the knob sideways (IN- OUT) it automatically cams the butterfly down to the drawbar.

[BobWarfield]

BTW, you can get 2/3 of the value with butterfly impact wrench handheld too. They're cheap. Pick one up!

Cheers,

BW

[dp]

BTW, you can get 2/3 of the value with butterfly impact wrench handheld too. They're cheap. Pick one up!

Cheers,

BW

You also built one of those, no? I'm pretty sure I saw one on your site, anyway. Excellent job on that site, btw.

[John Stevenson]

I had often thought about building one but a couple of things put me off.

One I don't really fancy beating up on a drawbar with an air ratchet, after using pullers with air ratchets it certainly wears the screws far more so it will do the same to the drawbar and collets.

I much prefer having to feel the tightness depending on what size cutter is fitted.

A simple quick job isn't easy if you don't have a tank of air up, in my case I have a rotary compressor that fills two 40 gallon tanks. I don't have the compressor on all the while and there may be a couple of days in the week where the tanks are empty.

The main reason though is my machine is a Varispeed and in low speeds the spindle isn't easy to turn by hand given there is only a small smooth diameter at the bottom.
I often have to turn the spindle to line the tool up with existing keyways and also sweep a dial gauge round for centering bearing bores.
I do this with a small 3/4" ring spanner on the drawbar.

Fitting one of these will get in the way for doing this.
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[Timleech]

The one reason I've wondered about a power drawbar is because my machine is quite tall, I have to stand on something to get a spanner on the drawbar which can be a pain if I have a series of tool changes to make. This type wouldn't help that at all, you still have to reach up there.

Tim

[John Stevenson]

Tim,
One of the web sites shows a similar home made changer that has a dog legged lever on it so the pullie down bit is easy to reach.
It may have been one of the guys off this site ?

This is one of the reasons why I hate R8 so much, at least with INT30 and 40 there is enough room up the spout to get a decent quick changer mechanism.

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