Indexing Odd Numbers

Forgot to mention that stepping the 5 and 7 segments out with dividers would likely leave pinholes in the finish turned piece. Though I guess I could do that if I's veeeeewy cauwfull.

Have you turned this already? How about a pentagon and heptagon - stick made - to slip over the form. If needed, build so that it can be assembled on the form - eg both ends too large to slide polygon over the piece. Build your polygons such that a circle the diameter of the correct place on the form can be inscribed within them.

LD

Have you tried indexing the chuck or faceplate? I once indexed a glue block.

Have you tried using a wire instead? I can't visualize the piece but I have in the past used a wire to mark off a path and then transcribed that to a piece of paper as a template.

A shot in the dark.

Mike

Metal milling machines have the same problem, for instance cutting a 37 tooth gear, that's why they have an indexer that can index any number from 1-300 or so. Of course they weigh about 300 pounds and cost $2000...

If you are going to do this often, then have a machine shop make you a new index plate for your lathe with the odd divisions not one your 96 plate such as 3, 5,

Hello Owen,

Do you have Woodturner-PRO program for segmenting? If you do, design a ring with and odd number of segments to fit your needs. Print it out and paste it to a wooden disk. Make a saw cut at each mark seperating the segments. Make sure you drill a hole to fit over your spindle. You can then make up a locater out of an old saw blade to fit in the slot you cut and you have an odd number indexing head. The disk will fit behind your chuck or faceplate. If this is not clear, e-mail me and I'll try to make it more clear. If you don't have Woodturner PRO, let me know and I'll make you up a drawing for you from Woodturner PRO.

Fred Holder

If not, I have a web form that at least does the math and printout for you:

Owen, I make indexing systems for woodlathes. Contact me through my website and maybe I can help you out with a custom indexing plate if you wish. Our stock plate for either 1 inch spindles or 3/4 inch spindles have two rows of indexing holes. The first row of 72 holes are 5 degrees apart and the second row of 20 holes are 18 degrees apart. Tim Q "A-LEE-SAM"

I have an exel spreadsheet that will give x and y co-ordinates fo points on any pitch circle diameter for any selected number o divisions. With this you could calibrate your face plate for this job If it of interest e-mail me Tony Ashgrove at snipped-for-privacy@yahoo.co

Can you role a large piece of firm paper into a cylinder and place it around the circumference? If yes, that will allow you to convert the circumference to a straight line (when you lay out the paper marked to the circumference length). Divide the length into your desired number of points and mark them on the paper. Place it back around the circumference, and mark off the points (maybe onto some easy removeable tape). Good luck, Alan

Thank you, EVERYONE! I think I solved my problem by taking a little bit of this reply and mixed it with a little of that reply and that reply...

Here's a picture of the project I was working on - you'll note near the top there are shiny things - these are two rows of blinking LEDs. The upper row has 5 lights the lower row has 7 lights (though you can't see them on the right part of the cone in the picture, the lights are evenly spaced around the circumference).

tape which will follow the curve but when I removed it to mark out the

I ended up using Adobe Illustrator to draw two stars - one with 5 points, one with 7, inside an 8" circle with a spindle diameter center circle. I aligned everything to the center and drew lines bisecting each point to make the point "sharper" to my eyes. Printed it, spray mounted it to a cardboard disk and cut the outer circle and then the center hole so it slips snugly over the lathe spindle and up against the shoulder.

Since this was only for marking out and was not needed to lock in position for carving or whatnot, I was able to set the tool rest so that it spanned the index wheel and the area of the turning I needed to mark (in this case indicating where to drill the holes for the LEDs). Using a #2B pencil I marked each position where the appropriate star's point was aligned with the top of the tool rest.

I could have made notches in the cardboard and set up a paperclip "pin" if the tool rest hadn't spanned the entire distance from cardboard to turning.