Thread: A Saturday at the backyard foundry

Hi BT,

You can join the queue for the MAHO, it's running a retrofit EMC2, and with the high speed spindle, it's a perfect machine for pattern making.. ( as well everything else.. )

The high speed spindle motor mount that Nick is manufacturing would be perfect for a CNC router.. (I'd suggest send him a PM if you want to buy one ) , is some very clever casting and well thought out design.

Half the pattern looks like this. It's done with a match plate with a core through the middle..



If you notice the reservoir opposite the mounting plate, that part of the casting stays in place and balances the motor mounting plate while boring the inside.. Then gets cut off later.

This picture I had to get from the video, my picture didn't come out as I would have liked.


There is a video with more on the Maho making the pattern..

Backyard casting: A HF-spindle-mount + "exhaust" - YouTube

To back up a little, Whats the idea behind the vacuum pouring?

Hi Stuart, check out the wall thickness in that video! getting the wall thickness of the exhaust part, as thin as Nick is getting, is why vacuum casting.

Hi Nick, What was the material being used for the pattern.. I remember it being mentioned, but with my memory I've forgotten already..

Still amazed by the stuff you are making...

Regards
Ray

Hi Stuart, check out the wall thickness in that video! getting the wall thickness of the exhaust part, as thin as Nick is getting, is why vacuum casting.

The exhaust wasn't vacuum cast. Plain vanilla sand casting. But it took some trials to get the in-gates right.

For the counter weight on the spindle mount:
I do bore it in the lathe with a purpose made jig. I didn't want to do that in the mill with a Wohlhaupter. Feeding is time consuming and a boring bar with 175 mm length and 18 mm shaft ... oh well!
In the lathe, I do it with a boring bar with 40 mm diameter. 800 RPM is no problem with the counter weight. And I just have to hit the start button.

The material is Renshape BM$whatever. They do have hard to remember numbers. It is similar to Ureol 700. That's for the "brown" (how they call it) stuff. The green one is a denser variety. The green one needs no sealing/painting. The beige one likes a cover of pattern paint.
If used for the core boxes (beige one), I brush on a release agent, no paint. Paint together with my core sand binder is a bad idea, the binder likes to stick to it.


Nick

Hi Nick,

This stuff? FMSC - RenShape BM-70

Originally Posted by Machtool

Wow! I’m officially jealous.

Sorry, I wish you were there too, you have a lot in common, and I think you'd have had a good time discussing scraping and metrology stuff..

Originally Posted by Machtool

Nick, if you ever want a holiday down under, I’ll volunteer to look after the Barbeque at the re-union and catch up with the other like minded people.

I'll second that idea!

Regards
Ray

This stuff? FMSC - RenShape BM-70

Yes. I looked it up, I use RenShape BM 5460. But in the datasheet of the link you gave, it says BM 5460 at the bottom.

I'll second that idea!

Thank you guys! But I fear that won't happen. Unless I win in the lottery (that I don't play at).


Nick