I spent the last couple of afternoons making the next part for my flame eater engine, the flywheel. Here I pose big brother flywheel along with the smaller version that you've seen before, if you're a long time reader.
The big brother is 3-3/8" diameter and the holes are 3/4" diameter. Little brother is 2-1/2" diameter and the holes are 1/2". Little brother is actually a bit more complex because the hub is threaded 1/4-28 for about a third of its length and reamed to 1/4" on the rest while big brother is reamed 1/4" the whole way.
Actually, this is my "done with the flywheel picture", but I realized I'm not really done. I realized that I haven't drilled and tapped the set screw holes in the hub. That will involve a setup that'll be a new technique for me, clamping the wheel to vertical surface with a spacer at the bottom to introduce that ~10 degree angle.
I wondered about the "10* angle" until I saw the drawing and saw why.ReplyDelete
Can't you clamp the flywheel to a drill press table and then tip the table 10 degrees?ReplyDelete
That's basically the trick. Since the drill bit is coming down from the top in that picture, that would mean tilting my table to 80 degrees, or clamping a 90 degree block to the table, clamping the wheel to that, and rotating the table 10 degrees. It's the same concept.Delete
Wheely nice job.ReplyDelete
Is the tap wrench going to clear the flywheel edge?
Is the center drill going to reach? Is anything going to reach and work?Delete
Does anybody make a 1-1/2" long 8-32 tap.
I looked up the prices for extended taps. Ouch.Delete
Probably a piece of drill rod or round stock with the tap soldered into a hole in the drill rod would work fine for tapping aluminum.
You may have a pin chuck among your jewelry tools that might work for the tap drill.
I would hope the tap has a point on the shank end. If so then you could align it and give feed pressure using a similar diameter rod with a matching conical hole in the end, held in the drill chuck. Give feed pressure with the quill handle, while turning the tap with a small wrench on the square.Delete
If there's no point on the tap shank end, you could add one on a grinding wheel with the tap in a portable drill. I get better results when I turn the drill slowly, otherwise there's a resonance with the tap bouncing off the wheel face and the point ends up off-center.Delete
Show your individuality. Instead of 8-32, make them M4 x 0.7mmReplyDelete
And offset them 180 degrees for balance purposes. Can't have the engine vibrating because you've got a load offset now, can we? It's not like you're going to get both set screws to be the same mass as the material you remove to install them.
Put the tap in the drill chuck after you've drilled the hole. Then turn the tap in by hand. That way the tap will be aligned with the hole you just drilled.ReplyDelete
I enjoy your blog.
At this point, the drill chuck can't get close enough to the center to hold a bit. Still working on it.Delete
Try holding the tap with a pin vise.ReplyDelete