Variable speed control in bridgeport boss 5

Wildeyedsboy · Dec 5, 2020

I am working on a Bridgeport Boss 5 and unable to find any manuals diagrams or references to the mill. I upgraded to current control electronics but can not get the variable speed adjustment to work. It appears that with the motor mounted underneath that they would have just reversed the assembly but it is not the same. Is there anyone who has a parts diagram or a illustration of the parts. I am thinking it is just missing a snap ring but not sure without seeing a picture.

Thanks in advance.

the spin doctor · Dec 6, 2020

I have a Bridgeport Boss 6 machine but the variable speed control is manual not computer controlled.

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gustafson · Dec 6, 2020

Most of them are driven with an air motor, so ther eis a fwd and rev air solenoid
And of course as with all varis the spindle must be turning for it to operate

legendboy · Dec 7, 2020

I replaced my Boss 8 variable speed drive with sheaves and bushings. 2 sets actually, 2:1 & 1:2. I have never had the need to move the belt to low speed. If you have retrofit the machine, throw in a VFD to control the motor. I had my spindle rebuilt and ground by CM and had some upgrades. I can run my mill up to 6800rpm and stop the spindle in less than 4 seconds. Had my spindle motor balanced by a local motor shop.

Only caveat being if you switch to mechanical low range you need to put the ac drive in reverse rotation.

I can post the drawings of the original air motor driven variable speed split pulley arrangement if you want.

Cheers

Wildeyedsboy · Dec 9, 2020

Thanks I am thinking of going with fixed pulleys as I already have the VFD installed. I found a post where a guy ordered parts for his and sent him an email. if he does not respond I may touch base with you.

Wildeyedsboy · Dec 9, 2020

I am running a VFD and that is controlled by a PDMX 107 and 126 board. Tore apart the variable drive and thought I found the problem but after replacing a couple bearings and reassembling still not functioning correctly. Looking at doing a fixed pully setup.

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Variable speed control in bridgeport boss 5

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