Lathe substitute centering tool needed.

[69427]

As the title implies, I don't have a lathe. However, I'm trying to do some grinding/reducing of the OD of a distributor piece (the points cam).



I'd like to chuck it up in my drill press to spin the thing, and then make a grinding/sanding fixture to remove the cam bumps and a bit of the OD. To give you some idea of what I'm looking for (unless there's something a bunch better) I need something with perhaps a 1/2" shaft (to fit my drill) and two cones that slide over the shaft to center the cam piece bore (that the distributor shaft slides through).

Any thoughts or suggestions? This is just an experimental project at the moment so I don't want to spend serious money at a machine shop.

Thanks,
Mike

 

[69427]

Well, after playing around I think I might try cutting a spare distributor shaft to length (about 4 or 5 inches) and using a couple set-screw collars to hold the piece in place. I think that might work.

I'll hit up one of the local hardware stores tomorrow and see if I can find a couple collars.

 

[MYBAD79]

Have a look at a Dremel adapter for sandpaper rolls. It's a round piece of rubber that is expanded by tightening a screw, something like this should work for what you want to do.... they say it's 1/2"

 

[Ralphy]

One problem with a drill chuck is it will probably not spin true, you will have some runout. If you lived in GA I could do it for you. That looks like a quick 15 minute job. A shop shouldn't charge that much.

You could mail it to me with exact instructions.

MyBad the sanding drums would take a long time and lots O drums. Unless you grind the majority off with a pedestal grinder then finish.

 

[MYBAD79]

Ooops, I guess I wasn't very clear..... try to use the rubber adapter to clamp the bushing (instead of the sandpaper roll). Then put that in the drill and see if it runs somewhat true....then clamp the drill in a vice and take a file to the spinning bushing ... it might work .....

signed: Bubba McGyver

 

[Ralphy]

Rubber arbor, good idea!

I use those often, 1" and 2". They tend to be off center a bit but if you play with it a little you can find true. The two inch really suck, If you spin them fast not being against something, they jump way off center. Then the die grinder shakes so much you almost can't hold on.

 

[vette]

How about a carbide reammer? Or like the others say, bring it to a shop..It's about a 15 min job..

Danny

 

[69427]

How about a carbide reammer? Or like the others say, bring it to a shop..It's about a 15 min job..

Danny

It's a prototype part. I can't afford the machinist's time while I keep tweaking the part size to see what the appropriate interference fit needs to be. I'm reducing the points cam OD along with hogging out the ID of the reluctor wheel. I've also got an HEI reluctor wheel that I'm considering trying to fit onto the old points cam piece. Lots of unknowns at this point.

 

[BBShark]

So your going to reduce the OD of the points cam and increase the ID of the reluctor wheel? How much will you decrease/increase (how much material are you removing)?

Do you have a centerdrill? I might have low tech way to do this.

 

[69427]

So your going to reduce the OD of the points cam and increase the ID of the reluctor wheel? Yes. How much will you decrease/increase (how much material are you removing)? I'm looking at roughly .050" off the cam at the moment, and about .250" increase in the ID of the reluctor wheel so I can press them together. These numbers may change as I'm currently disassembling an HEI part to possibly use that reluctor wheel. Do you have a centerdrill? I might have low tech way to do this.

I'm just a double E (with no business doing mechanical stuff :amused. What's a centerdrill?

 

[Ralphy]

https://alliance.seas.upenn.edu/~medesign/wiki/uploads/Software/centerdrill.jpg

 

[BBShark]

Are you familiar with the expanding anchor bolts that are sold at Lowes? There is a particular type that has a split steel tube around the outside. You could probably use one of those to chuck up the cam. Might take some messing about but there is a good chance you could get it to run true. Also they come in 1/2 inch OD.

For the reluctor, do you have a drill for the ID or were you going to grind that out?

 

[69427]

Are you familiar with the expanding anchor bolts that are sold at Lowes? There is a particular type that has a split steel tube around the outside. You could probably use one of those to chuck up the cam. Might take some messing about but there is a good chance you could get it to run true. Also they come in 1/2 inch OD.

For the reluctor, do you have a drill for the ID or were you going to grind that out?

I ended up cutting up a distributor shaft from an old HEI yesterday as that fits the ID of the cam/advance weight unit, and then picked up a couple of 1/2" ID set-screw lock collars to fasten things, and the shaft fits my drill press. So, right now I can spin the thing once I get the the "cutting" setup figured out.

I'm still trying to figure out how to hog out the reluctor wheel. I need to take the ID to about .940". I may have to buy a one time use drill bit that's close (15/16" or ballpark, depending on the final size requirement), and then hone it out to the final size. I need to make it a press/interference fit over the "cam" face so it doesn't rotate/creep with acceleration or temperature.

As I mentioned before, I'm also looking at the possible use of an HEI reluctor wheel, but I think the Chrysler wheel has a better magnetic path when used with the Chrysler pickup coil. Here's an old picture of stuff mocked up.

 

[BBShark]

Making a concentric/press fit is going to be difficult with the methods you describe. Not impossible but close!

How about grinding both the OD and ID with enough clearance to ensure you can mount the reluctor concentric with the shaft and epoxy it on? If you don't trust the epoxy by itself, drill a few 1/16 holes through the glue line (axial holes) that cut into the cam and the reluctor and use some roll pins? If you did this in 3 places, it should be work.

 

[69427]

Played around taking a little material off the points cam. So far it's slow going, but I'm getting there. However, if I ever find a good deal on a lathe I'm going for it.



I'm using part of a shaft out of an old HEI distributor which fits the points cam setup pretty well. Once I get the cam ground down to where I want it I then need to bore out the reluctor ID for a press fit over the cam.