Otis, or machinist tool ????s

[pjtoledo]

what tool bit should I use to cross drill a hardened shaft?
1/16" hole, goes about 3/16" deep to hit the open center.

I was able to drill the top pocket easily, the sides just laugh at my standard bits. using Tap Magic and started with hi speed, no go.

this is the shaft for a 3.0 cam synchronizer. the plan is for an oil reservoir at the top filled with cloth or fiber and a cross hole to slowly release lube to the shaft. a hole in the center of the sync cap would allow easy access to add more oil.


yes, I know the hole is not centered, but it's within +/- .050 spec!!

 

[Dirtman]

Depends what you wanna spend.

That small any drill bit is gonna walk on a hardened shaft in my experience. .050 is alot on a small hole like that too. 1/16 is .062... so that bit is off alot!

My advice would be to use a 4 flute center cutting end mill. Since end mills cut flat they dont walk on a round shaft. I've cut some pretty hard material with just regular HSS end mills. You can buy them for 20 bucks.

If you're using a regular ole drill press take the handles off and use short bolts as handles. It forces you to make smaller slower corrections.

You also can't run tiny bits too slow or too fast. I cant give you exact rpm but im assuming you at least have a stepped belt you can swap. Google machinist rpm guide.

The lube, just drench it... im not a fan of tap magic but it doesn't matter much what you use for one hole. A thicker lube with higher sulfur will last longer before vaporizing.

 

[scotts90ranger]

In the past I drilled cross pin holes in the axles for a 1/5th scale RC car, front were mild steel and rear were hardened... I went to Harbor Freight and got some of their diamond drill bits, used a bunch of lube with a dremel I think since I didn't have a drill press at the time but they need to be ran fast and stupid slow

 

[pjtoledo]

used my Unimat mini-lathe in the vertical configuration to start the hole in the side. I have a 1/2"long starter bit, so that was no problem. just can't get anything to dig in deeper. the +/- .050 is a joke about the off center hole in the top.

only have a couple end mills, 1/4 is the smallest and that's way too big for this job.


I'm not a machinist, but I'm damn good at scattering metal chips around.

 

[Dirtman]

If you're not in a hurry I'll mail you a couple 1/16 hss 4 flute mills to try. I've got a box full and I cant remember the last time I used one. Pm me if you want them.

 

[pjtoledo]

thanks for the offer, I'm planning on visiting the local tooling supply tomorrow.

 

[pjtoledo]

I got it! rummaged around and found an old broken 1mm end mill. that penetrated the hardened outer area before it expired. then finished it off with a .033" drill bit so now the hole goes all the way into the open center.



I'll get a set of the cheap diamond bits and open it up more.

the shaft is 13.50mm / .531" diameter

 

[Dirtman]

Nice!

 

[91stranger]

Is this a common mod people do on rangers? I never heard of anyone doing this so that is why I'm asking. I know my CEL pulled a code for the cam synchro so I know I need to replace it soon. Is this mod to keep it oiled like they are supposed to so you don't end up with a seized engine? I'd like to see where this ends with a finished picture.

 

[pjtoledo]

Is this a common mod people do on rangers? I never heard of anyone doing this so that is why I'm asking. I know my CEL pulled a code for the cam synchro so I know I need to replace it soon. Is this mod to keep it oiled like they are supposed to so you don't end up with a seized engine? I'd like to see where this ends with a finished picture.

not really. it's something an old retired guy does when he needs "quality basement time".
this is mostly an experiment, the sync unit is from the rolled '99 I bought last summer.
yes this is to lube the top bushing.
took a few pics, I'll post them in the 3.0 forum sometime soon.

 

[Otis413]

Glad you got it!

I agree with DirtMan, and something I have done at home is use a grinder to make a very small flat spot to get a TiN coated drill bit started, use lots of lube/coolant, tap-magic or the like, even WD40 is better then running dry.