Riveting Smoke box- marking out

[ianmac]

Hello all,

I am intending to fab the smoke box over the weekend but i am not sure how to mark out the rivet holes.

What is the best way to mark out the rivet holes on a circle.

I was thinging someone might have an application that might draw some lines and i could glue it on then punch and drill or

work out what the radius is and work out the circumfrence and mark from there.

Any thoughts

[GWRdriver]

Ian,
I'm not sure if you are asking about marking the smokebox front or the periphery, in any case I'd now be tempted to use my dividing head but I've always had perfectly good results in the past marking them off on the periphery using dividers, beginning at the top, either on the centerline or astraddle it as appropriate, and allow any discrepancy which might creep in on the trip around to be taken up at the bottom of the smokebox where only Inspector Meticulous will look. Until lately I would have done the same for holes on a front, doing a couple of test passes to find the divider setting which most nearly produces equal divisions, but now I would do it using a Cad-produced degree wheel. Along those same lines, another way would be to mark off a strip of paper equal to the circumference and use that as a guide for pricking the drill points.

I once had a lathe (an Atlas) which had 360 indexing holes in the face of the spindle bull gear specifically to use for dividing. That was occasionally a very handy thing to have.

[ianmac]

Degree wheel

Googel found this for me!

It was for marking out the rivets on the front of the smoke box. Rivets take so long to do but they really add so much life to the model that you need them for realism.

www.lucasinjection.com/Degree_wheel_100.jpg

thank you very much.

[freddo]

Have you got a rotary table, Ian? On my buddy, Dr John's site, there is a picture of him drilling the holes in the smokebox using a rotary table on the drill / mill.

www.dr-john.org go to page 2 of the simplex bit.

Freddo