Bridgeport Varispeed spindle RPM dial

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Staff member
Global Moderator
Feb 17, 2008
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The Bridgeport 2HP Varispeed head has two small windows with the RPM for the high and low ranges showing through them. The numbers are small but adequate for those with normal vision. On a standard model the windows are about 5-1/2 feet above the floor. I have a CNC version so the windows are 6 feet above the floor.. Since I am a little feller that is about a foot above my eye level. With decreasing vision the only way I could use the standard dial was with a step stool, magnifier, flash light and then adjust the speed with my extra hand. So the giant dial was born.

Before starting set he speed to and easy to remember RPM. This makes it easier to set the pointer later.

The dial cover was removed (2 screws) and a mounting plate for the dial made up with a recess for the raised lettering and other features on the dial cover with mounting holes to match those on the dial cover. An oversize hole for the pointer shaft was drilled int the dial cover using the mounting plate as a template. The nut holding the original dial in place and replaced with the pointer shaft. The mounting plate and dial cover were installed using longer flat head screws.

I made my dial 7 inches in diameter. I made it out of black on yellow engraving stock on a laser engraver. It could be made by printing the dial on paper and gluing it a sheet metal disk. If made of paper I would suggest covering it with clear plastic or otherwise protecting it to make cleaning easier.

The dial was installed on the mounting plate and the pointer attached aligning it to the speed that that was set on the head before starting modification.

The photos show an unmodified manual model Bridgeport and the modification as installed on my CNC model.

Three PDF files are attached showing the parts and dial suitable for printing. The same files are included as DWG files in a ZIP file.

Gail in NM



View attachment all.pdf

View attachment dial parts.pdf

View attachment dial.pdf

View attachment Speed


Grumpy Old Git.
Dec 6, 2013
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North Yorkshire
Hi Gail,

That is very neat :thumbup: I can think of a couple of uses for your idea.
Thanks for posting it.

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