[dougputt]

Following the lead of many others who have installed VFD's on Bridgeports this is how I tackled it..

Removed all existing pulleys and fabricated two step pulley system for 12 groove poly V belt, one size gives 1:1 ration next step is aprx. 1.8:1
Fabricated front mount for spindle encoder to handle rigid tap and still be able to use power drawbar
Planning on using Pocketbike disc and caliper to replace removed factory brake, had to do it this way as ran out of room if I just placed step pulley on top of existing bottom sheave.
Cut out material above old vari speed motor to facilitate feeding a 6 groove poly V belt to drive encoder for rigid tapping.
Still more to do but it's coming along will post more.Attachment 217368Attachment 217370Attachment 217372

[dougputt]

Here is encoder set up on axis drives.

Attachment 217376

[sharp-shooter]

I'm in the process of doing the same thing. What encoder are you using on the spindle? Just wondering how many RPM the spindle will stand.

[dougputt]

I'm using the same encoder as I put on the axis drives, 8,000 count from Ajax. Works well and if I ever break a axis encoder I could use this one as a spare.

[dougputt]

Heres pic with encoder mountedAttachment 218972