Poor Man's Indexing/Dividing

[fluxcored]

Hi All,

I would like some suggestion and pointers on how to devise a cheap, quick method of indexing. It does not have to be super accurate - my immediate needs is to mark and drill some holes in a sprocket (I've already made a template but would like to be even preciser) and next I'll want to use it to cut change gears out of aluminium for my lathe.

I have'nt got a milling machine and still have to setup my lathe for some milling.

The sprocket is about 190mm in diameter - too large to fit on my lathe so using that for indexing is'nt going to work.

Maybe I should'nt bother with being too fancy with the sprocket - all I need there is to divide it into 8 equal sections. Time to use my spring loaded divider calipers?

Any help is appreciated.

[wheeltapper]

Hi
If its any help, this is how I did it.

http://madmodder.net/index.php?topic=3302.0

basically an expanding mandrel in the lathe shaft with a change wheel attached.

you would probably have to figure a different way to index than I did, I dont know what lathe you have.

it might give you some ideas tho.

Roy


edit
after reading your post again PROPERLY I realize you say you cant use the lathe so ignore my ramblings.

note to self ' read all the post next time!'

sorry
Roy

[arnoldb]

Hi Fluxcored.

The simplest way if you have access to a laser/inkjet printer is just to print a template; many computer drawing programs can generate a "star" with a selected number of points.
Tricky thing with a printout is that you have to check whether the printer actually prints in proportion top-to-bottom and side-to-side - easily done with a pair of compasses.  I used that method for some dividing that even my dividing head was not up to when I built my rotary table.

You can also use toothed belts (like used on car timing belts, printer head drives etc.) - cut it to a length that has an appropriately dividable number of spaces between teeth; measure the strip, divide by pi and turn a "ring" to glue this to; then make a simple detent device to index off it.

Circular saw blades can also be useful if you can get one with a suitable number of teeth.

I'm a bit closer to home for you than most members of Madmodder; phone calls to Namibia from RSA is not that expensive; if you want, I'll PM you my telephone number and you can give me a call so we can chat it out; much easier than doing email/posts.

Kind regards, Arnold

[BillTodd]

Can you use the sprockets own teeth?

Bill

[fluxcored]

Can you use the sprockets own teeth?

Bill

 

Bill, that will do just fine. It's a 48 tooth sprocket if I remember correctly which I got from my scrap pile.

Sometimes I'm trying to formulate complex solutions for simple problems.

Hello Arnold, nice to know that you're close by. I'm down in George so if you ever visit the Garden Route drop me a mail.
I'm probably going to confuse us both over the phone because I'm new to all this and am still learning all the terminology and struggle to express myself properly.

Only way I seem to make progress is intensely studying other peoples projects and learning from that.

Wish you were even closer because I'd really like some hands on tutoring.

Roy, your input was not wasted - I've long since wanted to do some dividing on the lathe and this looks a quick and easy way to do it.

Arnold, your belt idea is absolutely brilliant. I'm definitely using that.

[arnoldb]

Hi Fluxcored

I come down your way once in about every 2 years; my parents and grandparents live in Stilbaai, so I'll be sure to pop you a mail 
Was in George in February this year; went to check out the motor show there; some really nice cars they had there!

 , Arnold

[fluxcored]

Stilbaai - I'm envious, one of the loveliest areas around.

Let me know when you down here again - we can go for a beer. And bring with a milling machine while you're at it! 

Cheers.