Lock Bolt for a 1936 Ford Roadster Door Latch

[Karl1459]

We manufacture parts for antique Fords and needed a new source for lock bolts for door latches (an internal part of the latch). Previously we have had these sand cast/machined or machined. In an order to control costs we are attempting to have these investment cast and keep tooling in house. This obviously led us to FREECAD. After the steep learning curve of FREECAD and 3D Cad in general I was able to get a successful prototype.

The mold halves (and lock bolt) were virtulized in FREECAD, then an stl file to Shapeways, then molding the wax in house, then off to the foundry for the ceramic shell and casting in steel. The photo shows from left to right are the mold halves, the wax investment, and the steel casting. THANK YOU to the FREECAD team.

[jmaustpc]

Your first post welcome to the FreeCAD forums.

Could you please post your FreeCAD version data in the manner explained in the Help Forum "forum rules" link? Mostly for future reference.

Great to see FreeCAD doing real and useful things!

[Karl1459]

Your first post welcome to the FreeCAD forums.

Could you please post your FreeCAD version data in the manner explained in the Help Forum "forum rules" link? Mostly for future reference.

Great to see FreeCAD doing real and useful things!

Oops.

Freecad v.16
WinXP/Win10 (upgraded during project)

Thanks

[chrisb]

Great to see this, thanks for sharing.

[emills2]

That is a really nice looking casting.

Shapeways, then molding the wax in house, then off to the foundry for the ceramic shell and casting in steel. The photo shows from left to right are the mold halves, the wax investment, and the steel casting. THANK YOU to the FREECAD team.

would you mind telling more about the 3D print to wax process? did you print the mold then cast the wax into a positive? how much treatment did you have to do on the 3d printed mold? how many wax prints do you think you could get from the mold? how did you come out on man-hours versus letting your previous supplier do the tooling?

Thank you sharing

[Karl1459]

That is a really nice looking casting.

would you mind telling more about the 3D print to wax process? did you print the mold then cast the wax into a positive? how much treatment did you have to do on the 3d printed mold? how many wax prints do you think you could get from the mold? how did you come out on man-hours versus letting your previous supplier do the tooling?

Thank you sharing

As to cost, our prior methods were sand casting and machining, so not applicable. We were clearly not going to spend the money for a machined aluminum tool for wax injection, which is the preferred method at the foundry we are using, so they suggested we pour our own.

Our parts usage will likely be very low, in the 10-25 parts per year range so keeping tooling cost low is critical.

The ME factor is I have been making analog foundry patterns for years and truly enjoy it. So the step to 3D counts as fun time.

This was basically a test to see if I could learn to use 3D, if 3D printing from service agency was appropriate, and if I could make a viable wax out of a 3D mold. The answers were yes x3. The mold required no modifications and after several attempts I was able to pour successful waxes. Temperature of wax, release agent (heavy duty axle grease), and temperature of part when removed from the mold all turned out to be important variables. What I did is melt the wax in an open pot (NO OPEN FLAME!) and ladle pour into the mold, later I had the brilliant idea of using a 250 ml syringe (the wax shown was injected with the syringe, the casting was made from a ladle poured wax). The (nylon) mold shows no deterioration and as the wax is poured at 125-140 F, well below the melt temperature of the mold I expect a fairly long life of the mold.

While capable of making perfectly usable waxes there are issues with this mold, the draft is a little deep for easy release. The next version will have an ejector block to help remove the wax.

[mangaliron]

If you are having trouble with your door lock or need to find the correct one for your car, contact Phil Migliori in NY. This causes the mechanism to lock the out side door handle from rotating. The same is true of the 36 door latch mechanism.