[modeleng] Re: sprockets
- From: "R.L. Roebuck" <rlr20@xxxxxxxxxxxxx>
- To: modeleng@xxxxxxxxxxxxx
- Date: Mon, 30 Aug 2004 11:40:46 +0100 (BST)
Hi there Terry,
I'd suggest the following (hoping my maths is correct):-
Guess the number of holes - a good estimate would be to say that the
circumference of your 500mm sprocket is about pi*500mm, which is 1571mm,
and your pitch is 1/4"=6.35mm, which goes into the circumference about 247
times.
Divide 360 degrees with that number - leaving 1.4575 degrees.
Now draw out a right angled triangle in front of you, with one angle very
small.
Assume that this small angle is half of the 1.4575 degrees (0.7287
degrees), and that the side opposite this angle is half of your pitch
(1/8"=3.175mm).
The hypotenuse of the triangle should not be the RADIUS that you should
form the holes on for your sprocket for 495 teeth:-
hole radius= 3.175mm/ sin 0.7287degrees = 249.633mm
giving a diameter for your holes to lie on of 499.267mm.
This doesn't allow for any clearance between the chain rollers and the
sprocket though.
Hope this is of some use.
Yours,
Rich.
PS 247 HOLES!!! OUCH!
On Mon, 30 Aug 2004, Terry Lane wrote:
> I'm sure the info is somewhere but - have any of you got a quick way of
> calculating sprocket cutting. I got a job here that calls for a sprocket
> aprox 500mm diameter to drive 1/4" pitch chain. Now OK - the teeth gotta be
> one pitch apart, & the holes gotta be pin dia.+?, but how do I arrive at a
> pitch circle for the ring of holes?
>
>
> MODEL ENGINEERING DISCUSSION LIST.
>
> To UNSUBSCRIBE from this list, send a blank email to,
> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject
> line.
>
>
MODEL ENGINEERING DISCUSSION LIST.
To UNSUBSCRIBE from this list, send a blank email to,
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.
Other related posts:
