Thursday, May 20, 2010

No Drips Around Here

I received a package of custom gaskets from Cometic today. They are the largest gasket maker in the country, supplying both OEM and aftermarket manufacturers in a variety of industries. They were really easy to work with on getting several engine case and oil pan gaskets cut from their bonded rubber AFM material and on having MLS head gaskets made from a modified version of a ZX6R part.

The clutch cover, generator cover, and oil pan gaskets are made from a chemically blown compounded nitrile synthetic rubber that is bonded to an aluminum core so they have a bit of strength and won't just rip like paper gaskets. The process was simple, I grabbed an outline of the appropriate surfaces from my CAD model of the engine, saved them as DXF files, and emailed them. A couple of weeks later- custom gaskets for a very reasonable cost. Cool stuff.

They can do the same for just about any sealing surface so if you have an old car, tractor, vintage bike, etc. that is hard to find gaskets for just give Mike Sauer at Cometic a call.

Head gaskets are not as simple a part as an engine cover gasket. They need to withstand high temperature and pressure loads cycling at a rate of over 200 times per second. For this reason I did not want to start from scratch and preferred to modify an existing Cometic part. They were able to modify one of their .018" thick Multi Layer Steel head gaskets to add material where needed and then trimmed the overall length to size.

Overall all the parts were within tolerances, so one more item completed on the road to a running engine.

That's all for now.


Tuesday, May 18, 2010

The Eagle Has Landed, with video.....

Or the trunnion table has been mounted on the mill. Spent the better part of a day cleaning and mounting and aligning the table properly then a lot of productive time turning the jog wheel back and forth watching the table tilt. Much more fun than watching paint dry.

Here's a short video sequence showing 1, 2, 3, and 4 axes of simultaneous movement. Many machines are really 3.5 axis which means the X, Y, and Z axes can move or the 4th axis can move, but not all at the same time. This machine is a full 4 axis machine. The last move shows the X, Y, Z, and U axis in a synchronized movement.

This added capability enables making complicated and high tolerance parts with a minimal amount of re-clamping operations but is also possible to quickly damage the part, tooling, and machine with any incorrectly programmed move.

The next steps this week are to get the suspension spider fixture plate mounted and machined then make a sample part. I'll tackle this part first as it is pretty simple compared to the engine castings.


Tooling Board Pictures

Harmony/TPI just sent me some full shots of the pattern used for the front suspension spider and clip-on mount. They are interesting to see- besides the part geometry there are riders and sprues, both of which are much larger than I would expect.

The suspension spider pattern:

The clip-on mount:

The patterns are made from Renshape, a tooling board material that is easy to machine with a good surface finish. The pattern material is protected from the abrasive casting sand by the thin plastic film draped over it. I like the fact that the film has dual purposes: to improve the surface finish of the cast part and to increase the lifespan of the tooling used to make that part.

After a bit of necessary contract work to pay the bills I'm now in the final stages of mounting and aligning the trunnion table. A post will follow shortly.