[grandville455]

I was wondering can a guy drill out his .491 gear to .500 fairly easy if he has a drill press? Either that or does someone have a .500 gear they would like to trade? Mine is in excellent shape!

[66bonne]

Darby-P-Dude drilled mine out; no big deal.

Jim

[Sun Tuned]

Reamer would be best, but sure you could do it. Just a little plastic fantastic.

MSD ???

[grandville455]

Thanks, Jim Good to hear it can be done easily
Bob, The more I have thought about this i really like the new pertronix dist PNX-D120710
, Looks like a solid piece, and since my car is set up to run a pertronix anyway it just makes sense to go that route, plus they have a proprietary way to limit the advance whatever that may be kinda like MSD I am guessing just different?
something like this Bob?

http://www.tools-plus.com/irwin-11214.html

2995A74 mcmaster carr

[Sun Tuned]

Nah, lets just keep it simple.

If your nervous about it go buy a brand new drill bit , a nice new sharp one, and....

Drill baby drill.

A sharp bit will do that just fine. Like butter.

[goathead455]

I drilled mine with a new bit and a hand drill,no drill press and it worked fine.

[grandville455]

Originally Posted by Sun Tuned

Nah, lets just keep it simple.

If your nervous about it go buy a brand new drill bit , a nice new sharp one, and....

Drill baby drill.

A sharp bit will do that just fine. Like butter.

Thanks Bob, Not nervous was just wondering if it could be done without ruining it,lol..this is pretty straight easy just drill, not like setting the angle up when i did my metering blocks on my dom ,lol that took some adjustments

[Sun Tuned]

Lookit these things are like 100.00. I have no qualms about telling you I've driven in no telling how many roll pins in the last 15- 20 years. And I have no problem telling you guys my arse draws up tight enough to drive a 20 penny nail into it every time I put one on. Just makes ME nervous. They are a good piece and I have no issues recommending them over a bronze gear.

I do have one reservation about it though. I'm a worrier, I admit it. So take this for what its worth. The thing about a 1/2 inch bit is that I think when you get done that the hole will be slightly larger than .500 even if only by a couple thousands of an inch especially doing it by hand I would think. When you get done you don't want it to wobble on the shaft because if it does It will do same inservice and that we don't want. Would eventually make a nice wear pattern on gear from oscillating around some.

I haven't tried it on one of these gears, but I think I'd buy a drill bit just under .500 whatever it would be, as I'm not in my shop, might be a letter or a number drill. Get as close to .500 without going to .500 and then take some penetrating oil or even some 3 IN 1 oil and swab a brake cylinder hone in and outta there till you hone it out to desired slip fit.

I've done it with my hone on lower bushings and it fits fine. I believe if it were me, that would be what I'd do. You really dont want that gear rocking on that shaft, as far as long term reliability goes.

I know , I know I worry about too much. Let the laughing begin.

[grandville455]

Bob, that is the exact way I was thinking also with the .500 bit being to big to begin with, I do have a hand reamer bit not sure if it goes to .500 tho, But I agree I do not want any rocking!! I do have a letter drill bit kit too. I may just trade someone that has the bigger one and not worry, then we both sleep good at night! ,lol

[Sun Tuned]

Man dont sweat it I know you got a brake cyl hone and that will work just fine. Just be there a few more minutes thats all.

I'm just concerned drilling it right off with a 1/2 drill bit will leave it a bit floppy.

Fix the one you got it'll be less stress.

Mail it to me, I'll fix it for ya on the house.

[grandville455]

Send ya the gear u mean Bob? The msd box is wired for the pertronix, Just plug it in and go, no rewiring for the HEI, msd etc so either way, thats what i am running wether it be a new dist or i use my old points one, just like the features of the new is all. Only thing I am not sure on is where their vac starts etc

[Ollie]

Originally Posted by grandville455

Thanks, Jim Good to hear it can be done easily
Bob, The more I have thought about this i really like the new pertronix dist PNX-D120710
, Looks like a solid piece, and since my car is set up to run a pertronix anyway it just makes sense to go that route, plus they have a proprietary way to limit the advance whatever that may be kinda like MSD I am guessing just different?
something like this Bob?

http://www.tools-plus.com/irwin-11214.html

2995A74 mcmaster carr

grandville455
No. don't use a taper reamer.
you need to use a straight flute straight shank,
like this.
http://www.use-enco.com/CGI/INSRIT?P...&PMPXNO=945782

[Wade Congdon]

Originally Posted by Sun Tuned

I do have one reservation about it though. I'm a worrier, I admit it. So take this for what its worth. The thing about a 1/2 inch bit is that I think when you get done that the hole will be slightly larger than .500 even if only by a couple thousands of an inch especially doing it by hand I would think. When you get done you don't want it to wobble on the shaft because if it does It will do same inservice and that we don't want. Would eventually make a nice wear pattern on gear from oscillating around some.

This is exactly correct. A straight reamer is the way to do this. (Carbide if possible) Best way is in a lathe with the reamer in the tailstock. If you know someone at a machine shop this would be a 5 minute deal for them.

[grandville455]

Originally Posted by Wade Congdon

This is exactly correct. A straight reamer is the way to do this. (Carbide if possible) Best way is in a lathe with the reamer in the tailstock. If you know someone at a machine shop this would be a 5 minute deal for them.

Wade,
I do know someone at a shop, so just use a straight .500 one then? Or go smaller first?

[superdutybob]

I was a machinist in a former life. You're only talking about removing .009" total which is less than normally allowed to go from a drilling to a reamer. I would chuck it up in a small lathe and indicate it in so it's running true. Feed the .500 reamer in and it will be perfect. I wouldn't hesitate for 1 second to do it this way.

[Wade Congdon]

Originally Posted by superdutybob

I was a machinist in a former life. You're only talking about removing .009" total which is less than normally allowed to go from a drilling to a reamer. I would chuck it up in a small lathe and indicate it in so it's running true. Feed the .500 reamer in and it will be perfect. I wouldn't hesitate for 1 second to do it this way.

That is correct, We use a 4.998 but a .500 should work fine.