Aaaggghhh!!!!!!!!!!!!!!!!!

[ranch23]

You bet, removing the head can be fraught with peril. And yes the Acra is a nice machine, have Acra, Bridgeport and Wells. I would take a new Acra over almost any used machine.

 

[ranch23]

http://youtu.be/HFE_nXQCH6E, hey, if this link works, check this out, the job just got way easier!

 

[OldMachinist]

Like was stated above stay away from the cheap asian made bolts. The original Bridgeport bolts were alloy steel with cold formed heads and rolled threads, the cheap ones are turned from square stock and will break if torqued just a little over the 50 ft lbs specified. The manual says"Tighten the four unit head mounting bolts first to 25 lb-ft in a diagonal sequence then to 50lb-ft.".

In the picture the bolt on the right is a OEM Bridgeport and other is asian.

 

[ranch23]

Thanks for the info. I'm assuming torque specs and the like are available in the Bridgeport rebuild manual?

 

[OldMachinist]

The specs are in the full Bridgeport manual that you can download from Hardinge here http://hardingeus.com/usr/pdf/Knee Mills/SeriesIPartList4302Plus.pdf

 

[ranch23]

Got it, Thank You!

 

[ranch23]

Replaced the bolts in my head today. Will take longer to tell about it than it took to do it. Built that head holding fixture, and raised the table, puting the fixture in the collett, used the table to pull the head loose, replaced the bolts and we are back to tramming.