Drawing a saw blade – help!

[Model EnginerdParticipant @modelenginerd]

This was an interesting study. I tried an approach using expressions so the user could pick the TPI and diameter and the geometry would auto gen. I had 16 TPI in this one, which is pretty tight. Another design consideration was the outside diameter measured from the outboard cutting edges didn't necessarily match the pitch, so the pitch was adjusted slightly to meet the O.D.

Another thing is that I don't know how Alibre handles arc lengths. It doesn't do radians. I did manage to create geometry but was unsuccessful in automating all of the inputs.

In retrospect, as someone else mentioned, it would be better to force the TPI and the diameter together, so when the steel is rolled and welded, the teeth will be offset at the weld.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Model Enginerd on 03/12/2022 00:02:32:

This was an interesting study. I tried an approach using expressions so the user could pick the TPI and diameter and the geometry would auto gen. I had 16 TPI in this one, which is pretty tight. Another design consideration was the outside diameter measured from the outboard cutting edges didn't necessarily match the pitch, so the pitch was adjusted slightly to meet the O.D.

Another thing is that I don't know how Alibre handles arc lengths. It doesn't do radians. I did manage to create geometry but was unsuccessful in automating all of the inputs.

In retrospect, as someone else mentioned, it would be better to force the TPI and the diameter together, so when the steel is rolled and welded, the teeth will be offset at the weld.

Nice! My mind is mathematically weak and I hadn't thought of expressions.

Now the idea has been demonstrated, this might be the best way to do it. Kerfed teeth on a curve are a general problem like gears. They're drawn with a macro or built-in program doing the maths, rather than the operator tracing curves manually.

Dave

[David JuppParticipant @davidjupp51506]

Posted by Model Enginerd on 03/12/2022 00:02:32:

Another thing is that I don't know how Alibre handles arc lengths. It doesn't do radians. I did manage to create geometry but was unsuccessful in automating all of the inputs.

Alibre does do radians – but it will display in your chosen preferred angular unit.

Alibre works internally with radians, like many computer systems do – so an arc length is simply given by

arc length = radius * angle

Alibre's equation editor is VERY FUSSY about variable typing, which can lead to some unexpected problems if you are not aware of them.

This page may be helpful – it's on an old system, so could vanish (I can provide it as a PDF if needed).

[Model EnginerdParticipant @modelenginerd]

Awesome. Thanks for the tips. I'm still pretty new with Alibre.

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