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Mazak Draw Bar

cally

Plastic
Joined
May 14, 2019
Hello,

Looks like I may have to repair the Bellvile washers in my Mazak HTC-400 cause it keeps dropping tools. Just wandering if anybody had any experience with this or could offer advise on the drawbar removal. Mazak wants the spindle returned to them to do a complete rebuild $$$$. Any help would be greatly appreciated.
 
Buy or borrow a drawbar dynamometer and check retention forces before you decide it's the drawbar. Perhaps there's something wrong with the knockout actuator, or some related error. Best to have a solid identification of the problem before removing or otherwise incapacitating the spindle.
 
Are the tools coming out during cutting or tool change or just randomly dropping out? Has this been gradually increasing over time or just one day decided it didn't like holding tools and just spit it out? The reason I ask is I had a 400 a few years back and it just decided one day it didn't like tools and started dropping them. The tech came out and apparently there had been a power surge that glitched the software and just needed to be reloaded. I'm with Milland on this one. Before you go spend a pot load of money and a weeks downtime have the draw force checked.
 
The tools will sometimes fall out when doing heavy machining. drilling isn't a problem. Also, I can pop the tool holder out with a screw driver or small pry bar with very little force. I do not have access to a dynamometer but but I don't believe there is no where near 2000 psi. holding that tool holder in place.
 
The tools will sometimes fall out when doing heavy machining. drilling isn't a problem. Also, I can pop the tool holder out with a screw driver or small pry bar with very little force. ......

If it is that bad, besides fixing the drawbar, you'll need your taper reground too. Probably some effed up toolholders need to be pitched too.
 
Yea, we checked the Taper and it does not look good. Do not know weather to send the spindle back to Mazak or just look for another used machine with a good taper.
 
Based on the picture here.....

Mazak HTC-400 Spindle Repair - Northland Tool

It doesn't look like a tough spindle to pull. If it were mine, I'd pull it and send to a good local spindle repair shop. You may need to do some searching around for a good shop in your area.

I had Northland do a taper repair on a Haas spindle a few years back, they did a nice job. For whatever reason, NH has a bunch of spindle repair places, perhaps offshoots from older companies.

Cally, if you can't find a local company to do the work, then shipping to the Northeast shouldn't be too bad. I'd get a few quotes from the NH spindle companies and see what sounds best.
 








 
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