Cincinnati 205-12 lost the knee feed?

BobH · Jul 25, 2021

I've got a Cincinnati 205-12 that has been working fine for years. I just installed a DRO and ran the knee all the way down to check cable clearance and now it won't come up. The rapid turns the shaft on the front of the knee and the hand crank also turns the shaft fine but no movement in elevation. It didn't make any unusual noises and I've run it to the bottom numerous times with no problem before. HELP. Anyone have a clue what's going on? Bob

texasgeartrain · Jul 25, 2021

Without seeing the pieces in front of me, i would guess maybe the scew threads ran out past the nut. Or a keyway fell out, set screw loose etc.

Without accidentally flipping machine over, i might try raising the assembly by other means. But just slightly while i work the hand crank. Like a fork lift, overhead crane or something. You might catch the thread with a little weight taken up.

BobH · Jan 11, 2022

Just a follow up. When I ran the knee down last, apparently the brake on the knee was too loose and it ran away. When the knee bottomed out it sheared off the key and tore the threads off the elevation screw and out of the plate that transfers the rotary motion to the screw. After removing the elevation screw I turned off the remainder of the thread, keeping as much metal as I could and cut a new thread of a bastard diameter, then made a new driving plate to match. After reassembling things the culprit of destruction, the brake, only needed adjustment. The manual gives you nothing on this. On the left side of the knee, near the front is a slotted screw with a jam nut. That's the adjustment for the brake. It's just a pointed set screw. I turned it in until the knee didn't freewheel when coming down, an extra 1/8 turn for luck and everything has been good since. Bob

Dope · Jan 18, 2022

BobH said:
Just a follow up. When I ran the knee down last, apparently the brake on the knee was too loose and it ran away. When the knee bottomed out it sheared off the key and tore the threads off the elevation screw and out of the plate that transfers the rotary motion to the screw. After removing the elevation screw I turned off the remainder of the thread, keeping as much metal as I could and cut a new thread of a bastard diameter, then made a new driving plate to match. After reassembling things the culprit of destruction, the brake, only needed adjustment. The manual gives you nothing on this. On the left side of the knee, near the front is a slotted screw with a jam nut. That's the adjustment for the brake. It's just a pointed set screw. I turned it in until the knee didn't freewheel when coming down, an extra 1/8 turn for luck and everything has been good since. Bob

Thanks for posting this update. I had a bit of an issue with my knee dropping a bit after moving it, and I couldn't figure out why it was happening. I could only "fix" it by over-tightening the gib but that wasn't really an optimal solution.

BobH · Jan 18, 2022

Definitely adjust that screw. It was no fun trying to get the elevation screw out without being able to rotate the dam thing so it could be retracted! Bob

Elwood1968 · Jan 18, 2022

My Cinova 80 205-12 had the same problem when I bought it, and I got used to cranking it up and down, never letting go of the handle. I thought my Toolmaster was a lot of work with its manual-only knee crank, but this Cinova was a real chore. I expected to tear the knee apart to replace the brake clamps, since, as Bob pointed out, there is no explanation or even mention of the adjustment for the brake. One has to look very carefully at the exploded parts diagram in the manual to see that there's a set screw adjustment from the outside of the knee.

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Cincinnati 205-12 lost the knee feed?

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