pOWER draw bar for SX3 - For 'quick' tool change

Hi, Just wondering,

Has anyone seen a power draw bar kitset or even plans to go on a SX3? i seem to spend for ever when it comes time to tool changes, and i'd love to speed that up..

It would mean you would need a compressor hooked up to it that you would have to listen to all the time. Are you willing to put up with that? You might want to try having an old speaker magnet on the side of the head to hold your 3/4" drawbar wrench and either buy or make a collet lock so you don't need the spindle wrench. Once you loosen the drawbar you can hold the drawbar with one hand and turn the mill back on to power it out part of the way, put it in reverse to put the new collet on. You can also put a red mark on the bottom side of the spindle where the keyway is and a black mark 180 degrees from it so that you don't waste time turning the next collet trying to find the keyway. You'll know where it is! Also file angles at the beginning of all your collets keyway slots so that the keyway funnels into the slot.

I made a power drawbar for my SX3, here's a couple of videos...

https://youtu.be/kqWf4eFfkns

https://youtu.be/fJIvKl5c85I

It's powered by a 63mm piston running off compressed air, I have a 100L air compressor which kicks in after about 50 tool changes so it's not too much of a nuisance. It's a massive improvement to be able to quick change tools, also you get to program in tool offsets so you only have to zero once per setup. It is reasonably expensive however, I'm using Tormach TTS holders, I spent ~$1000 on parts and tool holders, and would still like more. Also you have to be more aware of tool pullout, TTS holders can slowly walk out if you take too deep a cut or have bad chatter. It's still definitely a worthy upgrade though, tool changes used to be drudgery but is now a pleasure :)

I don't have plans for these, but you can find a CAD model here, the main side supports and cylinder pivot block are aluminium, everything else is mild steel, the belleville washers are from Tormach and the cylinder from eBay. The design has a sliding plate that allows the power draw bar to be disengaged, when disengaged it allows you to use the hand feed, which is great when you want to do things like drill holes manually.

Probably the toughest bit of the build is threading the end of the spindle for the pull collar, you only have one chance to get it right! If you didn't want to thread the spindle you could make a collar to clamp on, though you would sacrifice a reasonable amount of manual feed.

Good luck if you decide to build one, make sure you post the results :)