Commando Crankshaft Porn

worntorn said:

The carriage handwheel is fully offset to the left away from the cross slide on the lathes shown in this thread?

Yes, we have moved from crankshaft porn to lathe porn :wink:

Glen

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That had to be a special order in NZ on a Colchester, carriage hand wheel fully offset to right hand, just curios.
Home shop machinist is well worth a look

Here is my contribution to the lathe porn, the Harris is the one at job i used for my crank, the other one is a typical well known Swedish Köping here, it is considered so good that the shop thought it worth renovate and put digitals on it.
(obviously you call it DRO?)





Glen, i think those old machies are a piece of art!
And yours must be perfect for making a crankshaft.
To keep to the subject:
Today i have talked to the shop who will harden the crank, their advice was to leave about 0,3-0,4mm, stress relieve it
(Jim, you mentioned heat tempering, same thing?) then turn and grind it finished measure.
Then he adviced me to micro carburate(correct english word?) the whole crank. It gives an 0,3mm hardened underlayer and a very thin and very hard surface, it also increasing strengts of the whole crank.
Afterwards you just take a fine emery and polish it.
I`ts a kind of Nitriding.
Of course there is other ways of doing it.

Looking forward for more machine porn, Jim, do you hav pictures of how jou turned out metal from that lump?

Sten

billet said:

Today i have talked to the shop who will harden the crank, their advice was to leave about 0,3-0,4mm, stress relieve it
(Jim, you mentioned heat tempering, same thing?) then turn and grind it finished measure.
Then he adviced me to micro carburate(correct english word?) the whole crank. It gives an 0,3mm hardened underlayer and a very thin and very hard surface, it also increasing strengts of the whole crank.
Afterwards you just take a fine emery and polish it.
I`ts a kind of Nitriding.
Of course there is other ways of doing it.

Looking forward for more machine porn, Jim, do you hav pictures of how jou turned out metal from that lump?

Sten

Click to expand...

Sten,
I started the material removal for the throws in the CNC machine. After it ran for a day I decided to try another method as it was looking like it would need to run for another week to finish the job.
I mounted four 14 inch cutoff blades side by side on my grinder spindle.
I had to replace the 1.5 horse low speed motor with a 5 horse high speed motor to drive them. Then with the cross-slide feed as slow as it would go and lots of coolant I put in my earplugs and let it go. It took about 8 hours to rough cut both throws to within 1/4 inch of the final size. From there I went back to a slow speed grinding wheel to finish the job.

I have not decided if I want to nitrocarburize the crank yet. It has it's advantages and disadvantages. I may leave it 'as is' after the hardening process unless I can find someone to plasma -nitride the journals only. Jim

1/8"~

Ed Geof Collins of Off Set Crank in Canada has arranged a shop to nitride cranks, so I assume could mask off what ya didn't want the hard layer on. Cryo tempering has -300'F and now -400'F available which works to the core and said should be done prior to final finish of surface and size. I believe this is what kept Peel parts from exploding on throttle sticking unloaded. Most amazing to me was DS crank bend could be measured by a ruler at
~ 1/8" off and TS ~1/6" but after 2000 more miles reduced back to normal by over half so needed dial guage again. That much bend tears up the alternator and cam tensioner and oil pump snout. Cryo is what allowed the rotary crank to survive to go into production as no metallurgy or other treatments could handle the thermal changes with spin loads.
Peel past and next edition essentially everything cryo tempered. May even cryo her tires as no Z rated in our size yet. Scan these for the sales pitches.

https://www.google.com/search?q=cryo%20 ... &source=hp

Jim, that`s really a sign of creative thinking!
To being able to solve the problem with the machine that are at your disposal.
About nitrocarburazing, when i talked to the man at the shop i mentioned the plasma nitriding but he recommended the carburazing, beig harder and tougher.
It was more expensive to nitride the journals only, i think it can be done with both methods if i got hom right.
To nitride the whole thing of course means you have to finish absoltely everything, including balance factor so that can be a problem.

Sten

billet said:

About nitrocarburazing, when i talked to the man at the shop i mentioned the plasma nitriding but he recommended the carburazing, beig harder and tougher.
It was more expensive to nitride the journals only, i think it can be done with both methods if i got hom right.
To nitride the whole thing of course means you have to finish absoltely everything, including balance factor so that can be a problem.

Sten

Click to expand...

Sten,
If I do nitriding, it will need to be plasma nitride on the journals only. I don't want to nitride the weights as I may want to change pistons in the future. A deep nitride makes it nearly impossible to do any further machining.
With plasma nitride you can control the depth of the white [hard-brittle] top layer. Knowing that Norton cranks are going to flex no matter what you do I would prefer a more malleable surface that is resistant to cracks.
Here is a little info on what I will likely have done. Jim

"GAMMA PRIME
The gamma prime plasma nitride layer is primarily used in areas where loading or impact may be experienced. The gamma prime is more ductile than the epsilon layer. The "white layer" or compound layer will only build to between 0.0001 and 0.0004". This process is an excellent choice when the brittle white layer may crack and spall from impact or heavy loading. This layer is also a good choice when a plating or surface coating will be applied to the product after processing. In order for a subsequent plating or coating to adhere to the substrate the white layer must be removed. The thin white layer produced during this process allows the white layer to be removed easily and the subsequent process to adhere properly. "

I don't know if it has been asked before, but why not put the counterweights on each side, very close to the crankcase shell :?:

Jean

Jeandr said:

I don't know if it has been asked before, but why not put the counterweights on each side, very close to the crankcase shell :?:

Jean

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I has definitely been a subject of discussion with many points of view.

My personal view is that the counterweight should be split evenly with the counterbalance for each cylinder split and located on each side of that cylinders rod.
On my crank it would mean splitting the center weight and likely adding some heavy metal on each side weight.

I probably will not add heavy metal to this crank but when I get to removing the excess counterweight that is present I will be splitting the center counterbalance and removing the excess weight from the center to move it closer to what I would consider ideal. Jim

I found out there Ain't enough cheek room for that many-much heavy metal slugs, which weigh a bit more than depleted uranium and may cost more to boot. Seems like in prior photo's can see example of slugs in cheeks to approach your good suggestion. Jim is advocate of heavy cranks for a number of reasons, smooth operation a biggie.

Drilling for oil.









Checking the flyweight now that the sludgetrap is bored to the final diameter and the oil holes are done. It balances at roughly 2200 grams so I have 6 to 700 grams to remove from the center counterbalance. That will be enough to split the center weight into two chops . Jim

I know some stuff and I have done a lot of interesting shit during my time on this planet. But frankly, I am in awe here sometimes.

Russ

Lol...

I give up.

That crankshaft is mind blowing, thanks for sharing the knowledge/experience. Last one is how I feel wrenching in comparison...

The crankshaft project?
Jim, I`m sorry to hear that.
It was great fun to follow your project simulanteously.
I have drilled the oil holes myself and done some more machining, i will post some more pictures soon.
1989 i tried to make my own crank but had to scrap it because i was too inpatient and machined off too much material.

Sten

billet said:

The crankshaft project?
Jim, I`m sorry to hear that.
It was great fun to follow your project simulanteously.
I have drilled the oil holes myself and done some more machining, i will post some more pictures soon.
1989 i tried to make my own crank but had to scrap it because i was too inpatient and machined off too much material.

Sten

Click to expand...

Sten,
No I have not given up the crankshaft project.

I just gave up deciphering snortons hieroglyphics.

I should have the crank ready for the furnace this weekend. Jim

Snorton74 said:

That crankshaft is mind blowing, thanks for sharing the knowledge/experience. Last one is how I feel wrenching in comparison...

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LOL. +1

I'll bet that crank would cost more than my bike!!!! Nice work Jim.

Thanks, all it takes is half a brain -if I had a whole brain, I would just go buy one.
No,
Actually, I like the challenge. Jim

comnoz said:

Thanks, all it takes is half a brain -if I had a whole brain, I would just go buy one.
No,
Actually, I like the challenge. Jim

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Hobbies don't have to make sense.