So I'm Looking for some Gears...... ?

[gregvasale]

some GM cars used what appear to be identical spur gear oil pumps. Don't know what Ford used, but Chrysler used a rotor type where lobes moved in and out of suitable cavaties as the pair of parts rotated. There has got to be an easier way because you're going to need to make a housing for the gears too. Are auto oil pumps not good for your application?

[Doug4d3s]

Separate oil pumps won't work. One set of gears has to do both.

I emailed one online place trying to describe what I wanted, but I didn't get a response today. I do know they can cut helical gears, at least.

I tried playing with the emachineshop program, but it's only for straight spur gears (AFAIK).

[dly31]

In case you had not thought about it, remember that helical gears cause end thrust when under load so your mounting and driving has to handle that. It may not be significant in your application.

[Doug4d3s]

Has anyone here ever used eMachineshop for anything they couldn't CNC themselves?

I set up a gear: 20 teeth, 25° pressure angle, 3/4" thick, a bit more than 4" diameter and with a 3/4" bore. The material I left it on was the cheapest kind of steel they had.
The estimate function said for six of these gears was a bit over $1000 for a ten-day delivery. About $420 for a 30-day delivery (~$75 each).
Does that sound correct? That seems amazingly high to me.
And these weren't even exactly what I wanted... the teeth were straight, and there was no keyway cut.

I didn't play with the estimator function much because any time I changed even one thing in the job, it took another ten minutes to re-estimate the prices.

[dly31]

I don't remember the details but the few times I have checked on custom gear making I was shocked at the cost and decided against it. I suspect your figures might be pretty typical.

[mechanicalmagic]

About $420 for a 30-day delivery (~$75 each).
Does that sound correct? That seems amazingly high to me.

An hour each, sounds quite reasonable to me. (Assuming $75 per hour.)

Dave J.

[tommy1010]

Go to the junk yard a get a couple of old power steering pumps. Presto! Instant oil pumps and very high pressure. They can run a log splitter. Disassemble for the gears if the casing geometry is wrong for you.

[dly31]

You may want to find out if any power steering pump you are interested in is in fact a gear type pump. Most of the ones I have seen are the type that has a lobed central rotor in an internally lobed outer rotor, kind of like an external gear in an internal gear. I think some are also vane type pumps. Either of these will pump oil but I do not know if the internals would be suitable for the rest of your needs.