SB9 - thread dial castings

[tcweb]

I had printed myself a South Bend thread dial years ago.
Last year a friend who has access to a NICE 3D printer made me one out of a composite plastic (nylon and carbon fiber I believe), and it works great.

Well that same friend just decided to get into casting, and this was his first project.

I think they are cleaning up nicely. I figured I'd sand blast them once I had them cleaned up, just to get that "cast" texture back.
I'm wondering the best way to finish them. I figure I ream the through hole to 5/16", and then use that for reference to drill the perpendicular mounting hole.

I also am guessing I'll get to use my boring head to clean up the inside of the dial housing.

Any thoughts or suggestions?

I know making an aluminum SB9 thread dial is overkill, but it just seems to go with the lathe. (of course after I painted the plastic/nylon one, you really can't tell it's not stock!

-Tom

 

[tcweb]

Oh, and any suggestions on what could be used to fill surface imperfections? Something like Bondo, but maybe epoxy? (then it woudl get sanded and painted, so wouldn't be noticeable)

I've never finished rough aluminum, other than maybe a powder coat finish for some car parts. (actually, a SB9 grey powder coat would be pretty awesome...)

 

[Superburban]

Is the existing hole all the way through? If so, I would consider reaming it, then mount the whole piece on a mandrel between centers, then you could finish the inside on the dial and gear areas, and have them centered on the main hole. It would even be easy to clean up the flashing left from the casting.

Cool project, cannot wait for updates.

 

[tcweb]

Yes, the hole is all the way through. He used a graphite rod in the mold.

I have to admit, I'm not quite following your approach. ARe you suggesting using the lathe to clean up the inside (where the dials go)? small boring bar might do that....

 

[Superburban]

Yes, my thought is the lathe. I find it easier & faster then using a boring head on the mill. That will also keep everything in line with the bore. On the mill, you will have to indicate both the center of the hole, and assure that the bore of the hole is inline with the quill travel. In other words, you need to clamp the piece so the bore is vertical, then get the mill centered on the hole.

On the lathe, with a mandrel, all the cuts will be referenced from the center line.

 

[graham-xrf]

I don't know enough about casting - so I ask..
Is this using 3D printing to make the pattern, used in a conventional sand-box casting method?
My next question is is about whether or not a hard wax form can be 3D printed, and used in a "lost wax" mold?
Apologies that the question is way beyond NooB. The pictures are great!

 

[Aukai]

I was going to suggest Devcon epoxy for aluminum, but I looked, and it's pricey for a filler.

 

[tcweb]

Yes, 3D printing was used to make the pattern. I’m not sure if there is a way to print with hard wax. It sure seems possible. I will do some asking.

I may have some Devcon epoxy, actually. I can see how well it sticks to aluminum. Given this part is not under a lot of stress or heat, I’m sure even bondo might work, but I want to avoid that out of principle.

 

[silverhawk]

I don't know enough about casting - so I ask..
Is this using 3D printing to make the pattern, used in a conventional sand-box casting method?
My next question is is about whether or not a hard wax form can be 3D printed, and used in a "lost wax" mold?
Apologies that the question is way beyond NooB. The pictures are great!

Actually, 3D printed PLA parts have a lower melting point. You can print in PLA, make your mold, and then use a kiln or an oven to melt the plastic out. It's commonly referred to as lost-pla casting. Go to YouTube and look for myfordboy. He has a massive selection of videos for casting aluminum. He starts out with pattern making, then moves to PLA.

joe

 

[tcweb]

Yes, my thought is the lathe. I find it easier & faster then using a boring head on the mill. That will also keep everything in line with the bore. On the mill, you will have to indicate both the center of the hole, and assure that the bore of the hole is inline with the quill travel. In other words, you need to clamp the piece so the bore is vertical, then get the mill centered on the hole.

On the lathe, with a mandrel, all the cuts will be referenced from the center line.

I will be getting back to this project soon. I had to move the lathe into the new shop.