Magnetically Sprung Wobbler

[ACHiPo]

I wouldn't scrap the first block. Put a plug where the oil hole would be & re-drill your air feed hole through it. You could move the oil feed hole, or not..
(You can always shoot a little oil at the bushing)

Guess what? Anybody who has built "anything", has broken taps, drills, & unfortunately, skin. Be careful!

You're doing fine. Keep going!

John

John,
Thanks. I forgot to mention the blood dripping from my knuckle yesterday. It's cool enough for no sweat, and no tears yet, but definitely had the blood!

I still have the first block. I have lots more aluminum, and it only takes me about 30 minutes to rough out the block.

Evan

 

[Ken I]

Ahh - Blood - The perversity of machinery - it never works until you have made a blood sacrifice.

Another one of Sod's Laws.

Regards, Ken

 

[ACHiPo]

Ahh - Blood - The perversity of machinery - it never works until you have made a blood sacrifice.

Another one of Sod's Laws.

Regards, Ken

Kinda like smoke in electronics--it never works if you let the smoke out.

 

[ACHiPo]

A little more progress today. Got all the holes drilled and tapped in the body. The JB Weld didn't cure overnight, so it deformed and leaked when I blew the swarf out of the holes. I dug it out and machined a nicer looking groove, filled it with JB Weld and brought it inside as I suspect the shop may be cold enough overnight to slow or prevent adequate curing.

Here's the completed body before digging out the epoxy. You can see how it collapsed after I touched up the edges on the belt grinder.

Taped up to protect the finish and mask for the new batch of epoxy...

Will let it cure in the house until at least tomorrow afternoon. I can keep going on the other parts in the mean time.

 

[ACHiPo]

A little more progress today. Finished both journals for the crankshaft and got the main journal silver soldered to the counterweight disk. The MAP/PRO gas in a turbo torch worked ok, but I definitely need to get some fire brick and build an "oven" if I'm going to do much more of this (or get a OA rig).

 

[ACHiPo]

Well, today was very humbling. After machining off the excess epoxy (and being very happy with how it turned out), one of the vertical holes broke through to the hole below when I was cleaning out the epoxy. I may be able to drill and plug, but there have been enough "oopsies" to warrant a fresh start. Body #3 has been squared and marked.

I have to say, reading about model builds and seeing the pictures is a LOT easier than doing one! I keep telling myself I'm picking up skills in the process, but wow this is frustrating!

 

[Ken I]

Evan, Good going so far.

A word or two......

Measure twice cut once is always good advice.

When you are drilling, the start is the most important bit - dot down your spotting drill or centre drill (spotting drill is preferred) - measure between spots, edges etc. with a vernier - Not terribly accurate but it does show up gross errors (like a turn of the handwheel).
At these points errors are salvageable.
A poorly started hole always gets worse.
Drilling deep holes requires patience more than anything else. Anything over 5 times diameter is "deep" - The deeper you go the more you have to "peck" to clear swarf. My rule of thumb is 5 times followed by 60% down to drill size - so drilling a deep 2 diameter hole I would drill 10mm then 6mm then 4mm then 2mm for every peck thereafter. Clear swarf and apply lubricant at each peck.
Plan in your mind the complete sequence of machining a part before cutting metal - even the stock.
An old instructor of mine said "You can't put the machine in reverse and add the material back on".
Strangely I seldom mark out in blue preferring to pitch directly from my edge finder to centres - I do not recommend this practice but it (mostly) works for me as a form of mental torture to keep me focused.

Treat scrapped parts as learning experiences - I have a bin full of learning experiences.

Regards, Ken

 

[ACHiPo]

Evan, Good going so far.

A word or two......

Measure twice cut once is always good advice.

When you are drilling, the start is the most important bit - dot down your spotting drill or centre drill (spotting drill is preferred) - measure between spots, edges etc. with a vernier - Not terribly accurate but it does show up gross errors (like a turn of the handwheel).
At these points errors are salvageable.
A poorly started hole always gets worse.
Drilling deep holes requires patience more than anything else. Anything over 5 times diameter is "deep" - The deeper you go the more you have to "peck" to clear swarf. My rule of thumb is 5 times followed by 60% down to drill size - so drilling a deep 2 diameter hole I would drill 10mm then 6mm then 4mm then 2mm for every peck thereafter. Clear swarf and apply lubricant at each peck.
Plan in your mind the complete sequence of machining a part before cutting metal - even the stock.
An old instructor of mine said "You can't put the machine in reverse and add the material back on".
Strangely I seldom mark out in blue preferring to pitch directly from my edge finder to centres - I do not recommend this practice but it (mostly) works for me as a form of mental torture to keep me focused.

Treat scrapped parts as learning experiences - I have a bin full of learning experiences.

Regards, Ken

Ken,
Thanks. Really appreciate the encouraging words.

I applied most of your suggestions (spotting, pecking, lube, layout), but the epiphany I had a couple days ago was the need for a precise order of operations in my head. I decided to fully blue and mark the block after my first oopsie—which fixed that problem. I rely on my DRO for position, but the blue scribes are a good sanity check in case I forget to account for the diameter of the center finder. I thought through things, and got better each time, but in the last case used a Dremel by hand instead of more precise method to clean out the epoxy, not adequately thinking about depth. Definitely lots of learning, and the frustration that goes with it.

Evan

 

[Ken I]

"Forget to account for the diameter of the center finder" - been there - done that !

While on that subject a caution - don't let your centre finder go near a NiB magnet it completely ruins it and you will make a lot of scrap before you figure it out.

Edge Finder Heads Up

If ever your edge finder starts behaving strangely - this is one thing to look for.

Regards, Ken

 

[ACHiPo]

"Forget to account for the diameter of the center finder" - been there - done that !

While on that subject a caution - don't let your centre finder go near a NiB magnet it completely ruins it and you will make a lot of scrap before you figure it out.

If ever your edge finder starts behaving strangely - this is one thing to look for.

Regards, Ken

That's a new failure mode to me. Speaking of magnets, the batch I bought for this project have gone missing. Probably stuck to something somewhere!

 

[James Barker]

AchiPo, am watching and remembering many of the same "ah crap" moments as you have endured. This is only a hobby I tell myself, and although I do not like doing things twice (or more) it is therapeutic none the less and provides enormous satisfaction to me when that EUREKA!! moment arrives. Like Kenny, I have a drawer full of *ahem* failures. all ready for a repurpose in life, maybe, maybe not. Keep after it and you will succeed and be sure to tell us all about the adventure......

BC1
JIM

 

[Ken I]

Thanks to the 3D wizardry and compliments to Johnmcc69 - an animation of the motor :-

Animated / Partial Wireframe

Regards & Thanks To John

 

[ACHiPo]

AchiPo, am watching and remembering many of the same "ah crap" moments as you have endured. This is only a hobby I tell myself, and although I do not like doing things twice (or more) it is therapeutic none the less and provides enormous satisfaction to me when that EUREKA!! moment arrives. Like Kenny, I have a drawer full of *ahem* failures. all ready for a repurpose in life, maybe, maybe not. Keep after it and you will succeed and be sure to tell us all about the adventure......

BC1
JIM

Thanks Jim. I'm on a bit of a hiatus as I'm back at work and have moved to working on improving my lathe spindle. Hope to get back to the engine after I finish a spanner and increase the spindle bearing preload on my lathe.

Evan

 

[ACHiPo]

Hiatus continues. I'm making progress getting the spanner fabricated for adjusting pre-load, but it's turned out to be a much bigger job than initially expected (hogging out 52 mm diameter 80 mm deep to slide over the outboard spindle. Once that's done I need to fabricate the wrench portion)