Building a Deezil Pattern

[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 down. 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.

 

[maverick]

Steve,
Very nice work and a great idea for your club. Waiting to watch the rest
of the process.

Regards,
Maverick

 

[stevehuckss396]

Well I have the pattern completed.You can see on the back side where I screwed it up a little bit. It is
only the runner so I didnt worry about it. The Cases got a little also but that will be machined away.
All that is left is figuring out how to remove it from the sand. I'm not sure what to do. I'll figure out
something. Then 2 coats of clear and done.

　

The nose pieces are pressed in. I have to ask rick if he wants a radius at the base and if so, what does
he use for a job like that.

　
　

These are the rest of the parts. The large piece will form the infeed and the brass pieces will form the boss
on the rear of the case where the fuel system goes.

 

[Herbiev]

Following with great interest. BTW terrific photos

 

[stevehuckss396]

Well the mold was finally used today. Things could have been better. The pattern worked as expected. The shrinkage was exactly what was expected.

The bad part is I machined the thickness of the pattern what the finished casting should be so everything is too thin. I am a moron! Other than that the sand was not bonding very well and there were problems. I am going to make a new pattern and then I have to figure out why the petrobond is a little loose. More to come.

 

[procule]

I Steve,

You know, if you want to save your model, you have the possibility to oversise your model at the appropriate position, whit thin layer of shelf adhesive wax, disponible in .062 or .100'', i have used it in modeling project.

It's a possibility...

Procule

 

[canadianhorsepower]

Well the mold was finally used today. Things could have been better. The pattern worked as expected. The shrinkage was exactly what was expected.

The bad part is I machined the thickness of the pattern what the finished casting should be so everything is too thin. I am a moron! Other than that the sand was not bonding very well and there were problems. I am going to make a new pattern and then I have to figure out why the petrobond is a little loose. More to come.

Thanks Steve,
as usual when you do something you don't shoot blank
I.m following this oneThm:

 

[stevehuckss396]

Well I went out to make a new pattern but I just don't feel well. It will have to wait until I feel better.

Here is some very poor video of the first pattern of the day that went bad. I'll get it!

http://www.youtube.com/watch?v=xwVK9QAObNs&feature=youtu.be