Need slots on round part indexed, cannot afford indexer.

[maker of things]

I was thinking of gluing a printout of the pattern to the part. If I can make one good part I should be able to jig something up to use it as a pattern. I am a former carpenter and can probably get it pretty close but I'd like to get within .005 and that is probably out of my eyeball capability.

I meant glue the pattern to the fixture stock so you can located the indexing hole. Or very carefully lay out the pin position 18 degrees off of "12 o'clock". Every time you machine a "groove", you pull the pin and turn your part so the fresh cut is aligned by the pin. Should be pretty accurate.

 

[toolholder]

I meant glue the pattern to the fixture stock so you can located the indexing hole. Or very carefully lay out the pin position 18 degrees off of "12 o'clock". Every time you machine a "groove", you pull the pin and turn your part so the fresh cut is aligned by the pin. Should be pretty accurate.

Laying out the pin position sounds like the easiest, except for the part about being accurate. I have plenty of fixture stock so this may be the first thing I try.

 

[digiex_chris]

I actually use my lathe for this. I have a mandrel that fits into the back of my spindle that accepts one of my change wheels. I have an auxillary spindle that bolts down to a t-slot plate that bolts down to my cross slide. The spindle is just a taig headstock and a motor, really. I can chuck up a drill or endmill or whatever in the spindle and feed it into the work. I have a little sliding finger that engages the teeth on the change wheel so I can unlock the finger, retract it, count off the number of teeth to skip, and lock in the correct tooth, and repeat that way. Then it's just a matter of grabbing onto it with your lathe.

Heck, bolt a block on the back of the compound to hold a lathe tool, and you can drill the holes with the aux spindle, then run the lathe in reverse and trim off the outside of the holes in the same setup.

 

[toolholder]

I actually use my lathe for this. I have a mandrel that fits into the back of my spindle that accepts one of my change wheels. I have an auxillary spindle that bolts down to a t-slot plate that bolts down to my cross slide. The spindle is just a taig headstock and a motor, really. I can chuck up a drill or endmill or whatever in the spindle and feed it into the work. I have a little sliding finger that engages the teeth on the change wheel so I can unlock the finger, retract it, count off the number of teeth to skip, and lock in the correct tooth, and repeat that way. Then it's just a matter of grabbing onto it with your lathe.

Heck, bolt a block on the back of the compound to hold a lathe tool, and you can drill the holes with the aux spindle, then run the lathe in reverse and trim off the outside of the holes in the same setup.

I cannot visualize what you are describing, :think1:

 

[digiex_chris]

Managed to find photos. I don't have any on me of the rear of the spindle for the indexing, I'll grab some when I get home.

Cutting some slots around a cylinder (lathe as a rotary table, turned by hand)





(this was scary, don't do this, but it illistrates a quick aux spindle that could setup for drilling)


Then all you have to figure out is how attach a gear or saw blade or whatever to the rear of the spindle to use for indexing. And to be helpful, a positive stop that engages your indexing thing. I'll take some more pictures later.

- - - Updated - - -

oh! the first shot shows the degree strip I printed out and taped to the spindle! it worked well. Had to do a few tries to scale the strip right so that 0 lined up with 360 right, but was pretty handy for indexing for drilling operations, where the operation didn't really want to rotate the lathe spindle. Maybe not tenth of a degree accuracy though, depends on how good your eyes are.

 

[toolholder]

I like the degree tape around the spindle, have to put that on my to do list. Also I think I will start hunting parts to put together aux spindle, that could be a handy thing to have.

 

[CluelessNewB]

40 tooth saw blades are rather common (use every other tooth). Here is one for $15 at Lowes

http://www.lowes.com/pd_252909-70-DW3594L_0__?Ntt=252909&UserSearch=252909&productId=3451078&rpp=32

If you already have 5C collets you can pick up a cheap Spin Index for about $55 shipped on eBay.

 

[iron man]

Here is the saw blade I used it worked well a gear would work too. Ray

http://www.hobby-machinist.com/showthread.php?t=24787

 

[toolholder]

Here is the saw blade I used it worked well a gear would work too. Ray

http://www.hobby-machinist.com/showthread.php?t=24787

Very nice. I will try the 18 degree pin first and if that doesn't work I will go the sawblade route. It is nice to see others who can get r done with non traditional methods.

 

[digiex_chris]

almost exactly what I did, but the little brass bit engaged a gear tooth instead of a saw blade tooth. same setup.