Rotaryturbo

I was wondering your guys opinion on milling the rotors for 3mm apex seals. Do you think it would be alright to just have a local machine shop do it or do I have to send them to a place that rebuilds them to have it done right. My friend works at a machine shop and said they have the tools to do it right but I don't know.

Thanks,
Ben

Scalliwag

There are some tricks to it. A good machinist will figure it out on their own as long as you can tell them the clearance you are wanting. I cut mine on a horizontal mill. You have to have the rotor level so that when the bed is coming up into the cutter so the depth of the groove is correct at each side.
That sounds confusing but a machinist would know to look for that.

I made a jig plate that sits on my table. It has to short dowel pins that fit snug where the corner seals are.
I just threw a rotor on it and took a pic so you can see how it looks. I have a lock that sits on top of the rotor with a bolt to clamp the rotor to the fixture.

The best way is to have the seals and have the machinist measure them. There are conflicting opinions out there on how much clearance to use. I had a 1/8" "slitter" blade ground down at a tooling shop and then sent to Houston for a really hard coating (82 rockwell C) that is a mil thick. An 1/8" blade is a common size so they are pretty cheap. It is too thick so you have to grind it to the correct thickness. To be sure it is done right use a tool grinding shop.

I hope this info helps.

93redFD

I would let somebody that knows what there doing!! it better safe than sorry. I least the exsperts wont say"OOPPSS""I didnt me to do that" hehe

Scalliwag

I would agree it is best if you can find a shop that has done it before. But a skilled machinist would be pretty offended if someone thought they were not capable of something like this. This is a far cry from a difficult machining process. I can be messed up just as easy as anything else. It all depends on the individual you use and theat they have all the information they need.
On a scale of 1 to 10 for level of knowledge and difficulty it is a 2 at the most.