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Need knee crank for Cinci mill, 7 spline nubs

Cannonmn

Stainless
Joined
Jun 25, 2016
Need either center or left-side 7-spline knee crank that fits Cinci No. 2 horizontal mill. I had one but we received an OKK model 3 vertical mill with no head crank so we used the Cinci crank for that. It fit pretty well, I suspect OKuma copied some aspects of Cinci Mills. On the OKK, instead of the knee moving vertically, it is stationary and the head moves vertically. Who has one they’d sell me? I got one off Eboo once but there aren’t any posted now.
 
Fairly easy to make the clutch. 9 "tooth" here, Cinc similar with 7

DCP_0637.JPGDCP_0638.JPGDcp_0639.jpgDcp_0640.jpg

This was for a Ohio shaper - you could leave the "store bought crank" long for the mill - and bend it around to suit
 
Thank you for the input, johnoder.
This is about what I have in mind.
I was thinking of making the full length cylinder with the 'clutch' on the end but your photos gives me a more practical and efficient way to do it.
Yes... I believe my two CinCs have the 7 tooth clutch.
 
Hi, johnoder...

First, sorry about the photos I posted being upside down and now, gone. This is the first time I've tried to post photos and have been reading comments about how to do it but, have yet to figure it out, properly.
I've optimized photos/images for web-dev and think I'm an expert with MSPaint but figuring this out is taking more time than I expected.


Anyway...

I cut each side of each tooth (lug) in individual cuts.
From the measurement of the existing lugs:
- one from the Y-axis handle on the machine
- the other from the "female" of the Z-axis on the machine

I arrived at dimensions (worn, of course) for the actual shape of the lugs I felt I needed.

With that data, I created the shape (face) of the lug in Fusion 360.
Next, I built a "circular pattern", (cheating, I know) as it is called in F360 which gives the 360 deg/7 angle that you've specified.
Next, I performed a check of the angles of the sides of the lugs in F360 to ensure, as suspected, that they were not just half of the 51.428 degrees of the lug spacing around the circle which, was correct.
Off the centerLine of each lug, the angle was: 11.664 Deg (11' 40") roughly... which is close enough for this endeavor I think.

Note: From earlier programming experience, where we have to hand-draw all of our right-triangles out on paper and do all the calculations that we take for granted in SurfCam and Fusion360 and then, had to calculate arc centers and end-points/begin-points of arcs and offsets for cutter and rough & finish cuts and all, with an old Texas Instruments calculator, I know how to calculate these angels and now, am VERY thankful that I don't have to anymore simply, for the time savings and accuracy.

Once I figured what the lug side angels needed to be, I then compiled a list of 7 angles of one side of the lugs, indexed my rotary table to each of these angles with the offset on my Y-axis to account for my cutter dia. (.250) and then add the offset of these angles in relation to part center (.011").
The only thing left was to reverse all of this to cut the other 7 sides of the lugs.

Sincere apologies, for the length of this discourse.
From what I've read in your posts on the forum, I felt you'd understand my reasons for how I've gone about this exercise.

I will say that during the machining process, I found that my 1/4" end mill is, really too large to machine the lugs without clipping the inside corners of the lugs but it turned out not being enough to affect to overall function. A lessons learned, no doubt, but I got caught up in the lugs and angles and details and didn't go next step to be sure my cutter cleared, completely.

I certainly welcome comments/critiques on how I approached this.

This clutch fits both of my CinC machines, almost like a glove... all worn edges and corners, notwithstanding.

I'll make the extension for this clutch with the same inside/outside diameters, weld it onto the clutch body, turn it to blend and then begin designing, fabricating the handle lever itself and then make the actual handle (hand part... one that spins/turns) after that.

It's been fun and enjoyable and, a tad challenging, so far but, that's what being a machinist is all about, right?
 








 
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