indexing

[Guest]

I want to make an indexing plate to attach to my lathe but I can't work out a system to index the plate in the first place.I did consider drawing a circle on the computer with 15 degree quadrants but I don't know of a program to do this with. Any suggestions will be warmly welcomed

 

[orangetlh]

Ok this is maths so bear with me. You need to drawer your circle what ever size you need. then you need to work out the circumference. Do this by measuring the diameter and times it by 3.142. Then devide that amount by how many indexes you want on you circle, set a compass to that amount and mark each distance along the edge of the circle. Hopefully the last one whould meet up with the first!

 

[tibbs]

Try this - hopefully you'll be able to print it out in the correct aspect ratio - let me know if you want a larger/smaller one - only takes a couple of moments to do with a 2d drawing package (Ashlar DrawingBoard V1.0 from the Windows 3.1 era - ancient but works well).

Richard

 

[Guest]

Thanks orangetlh and Richard. The maths method involved fractions so I will go with richards print out.

 

[La Truciolara]

Jaymar

If you have the opportunity to get a Vicmarc chuck... all of them are indexed. It is quite convenient. :wink:

 

[Chris Knight]

I am afraid that Orange's method will also lead you up the garden path - it gives the arc length of each segment, whereas marking them out with a compass or dividers will measure a chord length.

 

[cd]

Jaymar,

I don't know if this will help at all but I recall reading an article on making a homemade indexing ring from a sink strainer like this. Unfortunately I cant remember where the article was but it basically involved drilling the center out to match your headstock diameter, then using it like a big washer between the chuck and the headstock. Apparently the holes are pretty accurately spaced so you would then just need to rig up a pin to locate in them. I hope this makes sense.
If I find the article I'll post a link.

cd

 

[geoff_tulip]

you can make the angles by continuously bisecting the previous angle using a compass. ie to bisect a 90 degree angle - with the point of your compass in the centre of your circle draw an arc approx greater than half the radius of the circle until it meets the the two sides of the angle you want to dissect. make a mark at each intersection. again with the compass draw an arc frm each of the marks towards the centre of the angle - where these meet is the centre of the angle. draw a line from cetre to this point and the angle is halved. continue until you have the whole circle -
takes longer to explain than to do.
good luck

 

[jasonB]

less than 50p spent a WHSmiths will buy you a plastic protractor, a little more for a circular 360degree one, just mark of the angles on a bit of card.

Jason

 

[JFC]

Indexing :-k Now what kind of machine has that already in its capabilities eh ...... The Legacy \/
Try woodworkers workshop . They have the indexing parts but im not sure if you can buy them separate .