Step block question

Correction to the pdf file. I found the test bar from a couple of years ago. I have that bar should be at 10 Degrees not 30 and the depth is .875. The 1/8 vertical seems to be ok. The 60 degree face is correct. I really need to get back and finish this and lock in dimensions. If you get yours done, please post final dimensions and angles. The test bar I made is close but not right.
 
Chewy said:
Correction to the pdf file. I found the test bar from a couple of years ago. I have that bar should be at 10 Degrees not 30 and the depth is .875. The 1/8 vertical seems to be ok. The 60 degree face is correct. I really need to get back and finish this and lock in dimensions. If you get yours done, please post final dimensions and angles. The test bar I made is close but not right.
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Good you made an update. Thought something was off, but couldn't put my finger on it.

Made a CAD model for both the block and the clamp. I just put them together in an assembly drawing and can see clearly I have a problem. :( Yeah, the teeth don't match! Whoops! I kind of winged these models, and it bit me. Inconsistently applied the constraints. Think I will put spreadsheets in each drawing to keep me honest. Well, guess I know what I'll be doing tomorrow. When I get the drawings consistent (and consistent with the block I have) I will publish a drawing. It's kind of hard to estimate the tooth depths, since the edges are rounded on the actual step block.

Just measured my blocks, they are 30/60/90. Unfortunately neither of my models are, and they differ. As they say, back to the drawing board! Got them close, but no cigar. Seems I am 2 degrees off. I'll get it, eventually.
 
Yup! I figured I was 1-2 degrees off but hadn't gone back to figure out why
 
mmcmdl said:
Just make them close to that . The blocks are made to pivot . ;) I have a drawer full if you don't feel like making them , and it's a large drawer . :grin:
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Of course you do :)
 
Hmm, a tricky geometry problem. Think I got it. This drafting tool isn't the easiest to make readable drawings, but it's the tool I have. The drawing isn't fully dimensioned yet. Missing the step offset needed to machine it when on an angle block. Anyways this is what I have so far. I used @Chewy's number of 1/16" for the step depth, this seems to be the same as mine. Forgive the excess decimals, haven't gone back to clean anything up.
m6stepclampcorrectedsteps.jpg
 

Attachments

For the record, the dimensions in the drawing above are incorrect. When I figure it out, I will post an updated drawing. I made a prototype piece in 6061 from my drawing and the teeth were clearly wrong. For updated drawings, please visit my thread in the Projects Sub forum. Sorry about posting a bad drawing.
 
ub27Rocks said:
Sorry for being a bit late but TE-CO supplies the cad drawings for their components: https://catalog.te-co.com/item/clamps-clamping-accessories1/serrated-end-clamps/30501

The angle is 70dg. If you have a horizontal mill there are cutters available that are just the right angle

View attachment 403205
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Thanks for the drawing. Next time don't be late for the party! :) Gee that would have been useful 6 days ago... Would have saved me a little time.

I don't have TE-CO step blocks, but some unknown clone. Using the same coordinate system, as in the TE-CO drawing, my measured angle is near 76 degrees, not 70. What is not explicit in that drawing, but I think one can work out via geometry, is the tooth angle which is 60 degrees.
 
Sometimes the 'close-enough' tolerance metric works ok. Generally the strap is not perfectly aligned anyway with the block. The main thing is to get a grip that won't slode off?
 
I measured my old set of blocks with the following results. step pitch, .1253"/step; horizontal change, .0619"/step,; vertical change, .1090"/step; and calculated ramp angle 29.56º.

In use, the angle of the step ledge probably isn't too important as when used properly, the clamp would be laid flat on the clamped surface and the clamp moved to the next step up. This results in just one step being truly engaged. The step pitch is the most critical feature but even that can be off slightly and still have the blocks function.
 
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