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m10 draw bar torque for threaded 30 taper?


May 15, 2022
I have just converted my Bridgeport to a 30 taper spindle. I have a haimer probe and height gauge along with a 3 axis dro so I can quickly change out tooling and set my z to zero with ease, along with the poor runout of the r8 spindle original to the machine are a couple reasons I have done this conversion.

I have a test bar and upon first test I was getting roughly 6μm of runout at around 190mm down from the bar, nearer to the top the needle barely moves.

Does anyone know what ft/lbs the draw bar should be torqued to? I have read around 25, some less. Should the tool fall out the spindle when you undo the draw bar or will it be slightly pressed in?

I just want to make sure I do things 'by the book', as I've spent some time getting things setup and am very happy with the results so far, I dont want to break a draw bar or damage the tooling or spindle..