*Knee Mill Retrofit*

[IJ.]

.....

[Cold Fusion]

Very nice work so far. Always overbuild is my rule. Most parts will be a pain to rebuild later so it's best to get everything 2x as strong as you need it because you never know what the future holds.

[Klox]

Ian, I'm impressed!

Klox

[Klox]

Ian, i've got a mill just like yours. I'm itching to convert it to cnc, however the funds are lacking at this stage. This is why i'm so interested in what you have done & how you have gone about doing the retrofit. At some stage i would be the one asking lots of questions......

Keep well,

Klox

[Klox]

Ian: I think my biggest obstacle would be the electronics side of things (I'm a BIG computor idiot! LOL!).
Maybe i could bribe Kookaburra to come and help me.....

The machining you did looks excellent, so neat!
Keep up your good work!

Klox

[Kookaburra]

Klox,

I'm up for bribes, lol. Maybe I could come over and first of all watch my rugby union team beat yours and then come and help you with the retro, lol.

[IJ.]

Klox: I think by far the hardest part and the most critical to get correct is the dogbone.

I machined a mandrel to a slip fit into the original hole once the brass acme inserts were removed and turned a 20 mm shaft on it on centre.(mandrel is 1.5" stepped to 20 mm)

I slip the mandrel into the dogbone then put the 20 mm shaft into a collet chuck in the mill then clamp it all in a Kurt vice to ensure it doesn't move.

I then make sure I can slide the mandrel in and out of the dogbone using the quill on the mill.
Mill to whatever size you need for the ball nut then turn 90 degrees and repeat.

I'm assuming when the dogbone was made they either used a compound 2 axis boring machine or some sort of accurate fixture so am relying on this for my set up.

Dave: If you're going remember to pick me up on the way out !!

[IJ.]

Today's progress !

I made the upper belt covers today and the bearing retainers for X and Y.

I also added another outboard bearing to support the handle shaft in manual mode (Not really needed but as I had a couple of spare angular contact bearings I figured why not)

Last pic is for ty1295 showing how my knee drive fits inside the knee.

[ty1295]

Thanks a bunch for pic.

I think you made my desicision on which way to go now.

I can picture it in my head now (little pun)

Your work on it is top notch.

[Klox]

Dave: I'm not into rugby! Yep i'm one of those few South Africans that's not rugby crazy! LOL! If i can arrange that the Aussie teams beat our local guys everytime you must supply all the spares as well! LOL!
Ian: I suppose you ended up with a stiff neck to maneuvre that drive into the knee, it looks very good/professional!

Klox

[IJ.]

ty1295: Very welcome.

Klox: Nah just drilling and tapping the 4 mounting holes was hard the install went smooth as silk and very quickly !

I'm making the lower belt covers and motor covers today then sort out the cable routes and I'll get into the X and Y BallScrews on Monday!! All downhill from here !

[Kookaburra]

Nice Limit switches Ian,

Looks like you are going to be using 6 overtravel switches and 3 homing switches, good move!!

Quality limits like those will give you a nice repeatable homing position, well done.