Using a Unimat SL1000 to Repair Itself

[Ulma Doctor]

I bought a used Unimat SL1000 years ago and have used it well.

It was not perfect when I got it, but I used her anyway.
She has some dings on the cylindrical ways …

I decided to retrofit hard chrome shafts in place of the standard soft steel ways she came with.

There is another caveat, i’m going to use the same machine to machine the retrofit!

I started with 12mm chrome linear rail shaft. It was about 40mm longer than the original ways, but that doesn’t matter, they will extend further into the headstock and will not be noticed when the headstock is in lathe mode.

I laid out, the hole positions on both shafts and drilled pilot holes with 3mm 2flute carbide endmills , while being clamped to the milling table accessory




After 3 pilot holes, the first carbide endmill broke.
The last pilot hole broke 2 more before I punched through the hard chrome and shaft.



The next act will be expanding the holes to 5mm and countersinking the holes for the oval head retaining screws!

More to come….

 

[wachuko]

Pretty cool. Following

 

[markba633csi]

Mine could benefit from that too- where did you buy the shafting Mike?

 

[Ulma Doctor]

Mine could benefit from that too- where did you buy the shafting Mike?

I’m pretty sure I got the shaft from EBAY, during the pandemic.
Look for linear rail 12mm
They were not terribly expensive
I’m sure they are available on Amazon too

 

[Ulma Doctor]

For those playing at home…
The hard chrome shafts are
12x330mm, they are approximately 10mm long from the OEM

 

[Ulma Doctor]

I had a little time to play with the retrofit.
I mounted a 2F 4mm carbide ball endmill in the drill chuck and found center on the previous set up and punched through the holes that were 3mm.
The ball endmills were beautiful to use even in the hard shaft.
I ordered a couple 5mm carbide ball endmills, but my desire to get on with the project, forced me to look into the carbide collection for an approximate .
I came up with a single #8 carbide stubby drill and thought that it was close enough to 5mm for the purpose.

I set up and punched the holes again to .199”


The carbide drill worked, but it took a lot of pressure to pierce the hard chrome and a bunch of peck drilling to get it done.

Have a look so far….




I’ll be chamfering the holes for the oval head screws in the next episode
Stay Tuned!

 

[Ulma Doctor]

Well I got her done today!

I got some carbide ball endmills yesterday afternoon and went to work this morning
I mounted a 7/32” carbide ball endmill and relieved the shafts




Then I moved to the 3/8” carbide ball endmill to finish

I gave her a little cleaning .
I deburred the shafts to prevent damage to the carriage during installation.


For those playing at home,
The 3/16” through holes are 295mm on center.

I swapped the shafts out and snapped a picture for posterity!



The carriage moves like glass!

I’m looking forward to continuing to test this capable little machine.
All machining of this project was performed on this machine.

Thanks for following along !

 

[ShagDog]

For those playing at home…
The hard chrome shafts are
12x330mm, they are approximately 10mm long from the OEM

Did you turn the shafts? Or did you buy them that way?

I'm following this thread with interest.

 

[Ulma Doctor]

Did you turn the shafts? Or did you buy them that way?

I'm following this thread with interest.

The best i can remember, I purchased the shafts from EBAY during the pandemic.
I didn’t need to turn them, the shafts are precision linear rails.
They are exactly 12mm diameter.

Thank you for your interest.