Retro-fit speed control to old Biax 7 EL

I just fitted a speed control to my older blue Biax and it came out so nice I thought I'd post it here.

First I robbed the speed control out of my el-cheapo mini-grinder. Makes no difference to the grinder - who uses them at reduced-speed anyway?



Then I took the cover off the Biax and offered the board up to the internals. No way it was fitting in there with the switch but it would go nicely in place of it. I milled a flat on the cover to hold the back of the control board, and also milled the two nubs off that hold the switch in place to allow the wheel to fit. Also see the hole for the retaining screw.



Next I cut a locating groove with the only cutter I had suitable - a dovetail cutter.



Board fits in just right now.



Very simple wiring. The little blue adjuster pot sets the minimum speed so you don't risk burning out your biax motor.

Looks like it was made to fit



Last job was to fit an old in-line switch onto the cord



There it is - one speed-controlled Biax.

Peter what a super idea....!!!!

Agree! I will be running to the shops to see if I find a suitable "victim". How come I never get these bright ideas..?

Nice work.

But don't think I'll be changing from my 15+/- years of merely plugging it into a cheapo $29.95 router speed control.

Also, per your note on "who runs a grinder at reduced speed?"
I have the same question about Biax.
The older blue ones run at 1200; seems slow enough to me compared with the modern green versions.

Nevertheless, well done!

smt

Jshaugjord said:

Agree! I will be running to the shops to see if I find a suitable "victim". How come I never get these bright ideas..?

Click to expand...

If it helps, Aldi in the UK are selling these grinders on offer for £20. If you like I can see if I can find one locally Jan-Sverre.

Stephen, I said the same thing until I had the chance to use one with speed control. Sometimes you just need it...

Stephen, I said the same thing until I had the chance to use one with speed control. Sometimes you just need it...

Click to expand...

Peter-mine has speed control - plugged into the all-purpose boxes sold as "router speed control". My speed control was actually first acquired to use with the big 'ol metal case single speed drill I put on my Mag-base/drill. It gets a lot of use there.



So usually I plug it in with the Biax as well. But hardly ever use it. When needed, because it is so seldom, it is not inconvenient to stretch a little to hit the control on the box, or clip it to my belt and adjust it there. I have used the green biaxes with the control in the handle, and don't find them any more convenient. The green ones do sort of need the control, though, because IIRC they run around 1500 at full tilt boogie.


smt

I just had to fit similar speed control to the other type of blue Biax (screwed-on motor instead of silver ring). These don't have enough room inside the casing for speed control so I 3d-printed a sleeve and spacer block.

This post is just so I can share the link to the files in case someone else fancies doing the same: