Supporting > Casting

Making a Deesil Pattern.

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stevehuckss396:
Things have slowed down at work and I'm back on a normal schedule. One of the things I did while
working was shoot off my big mouth and agree to make a pattern for a crankcase. Well I am finally
getting it done after promising many months ago that I would do it when I got time.

The prez of my metal club Rick does casting demos at the engine shows and some other clubs in
the area. Someone approched Rick at one of the shows about the Deezil engine. This fellow has
one of the castings for the crankcase but is afraid to machine it. He asked Rick if he could cast
practice cases. Well we figured why not. After the cases are cast he could still use the pattern
for his demo's and give the cases away to anyone who wants to build the engine.

Because there is no way to cast the cases exactly like the original, here is the plan. The cases will
be cast with MDMC (Metro Detroit Metalworking Club) on the front of the block instead of DEESIL.
This way the blocks we cast will never be confused with the "real" Deesil cases. The case will
be machined and a new crankcase drawing will be on our website for download. All the other
original Deesil parts will fit. The plans can be purchased on CD ROM from ron over at Model
Engine News.

After reverse engineering the casting I drew up the case in Alibre. Then I assembled 4 cases
on a hub and saves it as a STL file. The STL file was opened in CamBam and all the tool paths
were created. CamBam created some 280,000ish lines of code. I took the Gcode to the computer
in the garage and opened it up with Mach3 and here is how it went.


First roughing pass. The material was provided by Rick. It is called Renboard? It's kind of like a
cross between plastic and wood. It's very dense and stable. Machines real nice.

First pass




Third pass




Fifth pass




Seventh Pass




Ninth Pass




Roughing out complete





The center section was finished using a 1/8 inch cutter. The cutter started on the left side and went down
following the contour of the part. The cutter moved to the right just a few thou and went back up. The
process was continued until the center section was finished.





Then because there were some tight spots to get into, a 1/16 inch cutter was used to finish the rest of the
pattern.





Then the entire thing was cut out to the correct thickness to complete the first of 10 pieces.




The other pieces are simple and should not take long to make.

Jo:
Wow :o,

You make it look so easy. How long did it take to design the pattern using Alibre and then to convert it into a machining program?

Jo

ths:
Fantastic pattern, Steve, and it looks to have a superb finish. Is shrinkage allowance built in, and is there a draw taper there as well?

I'm not familiar with the engine, is there a link to find out more?

Cheers, Hugh.

steamer:
Cool Steve!...er ah "Bubba"!   Welcome Back!

I'm watching!

Dave

maury:
'396, You are doing exactly what I'm trying to set up to do. Very nice work! I have been making all of my patterns in the wood shop, and while it's relaxing and fun, I find my accuracy could be better sometimes, and the complex curves are difficult to match on the cope and drag. CNC solves that.
I'm just getting into Solidworks, an absolutely awesome piece of software, and will be using BobCam for Solidworks.

Been learning tool path options this week. I have a few questions, don't know whether it would be better to take it off line, or share with everyone on the board, may just add a lot of fluff. First off, I had a friend CNC a pattern for ma on my last project, and he used what looks like your Ren Board. Really nice stuff, found Freeman Supply carries it, same place I get some of my other foundry supplies. What tooling do you use to cut it, (HSS or carbide), and what feed/speed would you use to cut it. I want to set it up as a material in BobCad.

maury
www.lonestarengineworks.com

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