Chainsaw Repair
Chain - Grinders - Filing - Wood Milling - Tools - Welding - Machinist - Mowers - Tillers => Metal Lathe Milling Machinist => Topic started by: weimedog on November 30, 2015, 05:26:56 pm
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I'll tell you an idea I had .Machining rings for what ever size piston you are dealing with as far as OD of the piston,48-52 mm etc .About 3/4" wide maybe 30-40 thou thick .Just make a saw cut, one across it .In theory once it's in a three jaw it should clamp it dead on center . Just a theory .I never did it no more pistons than I work on .
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There must be a thousand ways to skin the same cat .Whatever works, works .
I have a Monarch 10" EE lathe with Cushman chucks . A 6",4 jaw, face plate and an 8" with long reversible jaws .Plus several more I haven't had the time to modify to take a D1 3 mount .
What works for me is clamping right near the ring groove using brass shim stock to soften the jaw bite so as not to mar the piston .I've even used the aluminum from a beverage can . With that you have to be very careful not to ding the part .Once again though methods mean very little ,results are where it's at .
Yup....remember making a perfect triangle to tease my boss once...cranked up the jaw pressure (air chuck), machined and threaded the inside diameter of a fitting....at 3500rpm...with iron chuck jaws....then cut the rpms to zero. The chuck crushed that part into a triangle now that the wall thickness was much smaller. Handed it to my boss and asked him how did I THREAD a TRIAGLE. He asked years later when I met him as an AE for a CAD/CAM company how I did that.
Part of the reason I took the approach I did was not to risk anything along the side of the piston and ring grooves. Since the cuts are small, the material aluminum, the parts relatively short, it works.
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There must be a thousand ways to skin the same cat .Whatever works, works .
I have a Monarch 10" EE lathe with Cushman chucks . A 6",4 jaw, face plate and an 8" with long reversible jaws .Plus several more I haven't had the time to modify to take a D1 3 mount .
What works for me is clamping right near the ring groove using brass shim stock to soften the jaw bite so as not to mar the piston .I've even used the aluminum from a beverage can . With that you have to be very careful not to ding the part .Once again though methods mean very little ,results are where it's at .
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You could always make long aluminum internal jaws for a three jaw chuck and use those inside a cylinder to cut the base.
Also for cutting pop up pistons you can make/purchase piston jaws that clamp on the inside of the ring land and use the ring land surface to square the piston up.
Either of these on a good quality 3 jaw chuck will achieve acceptable accuracy since you'll make the final cut on the clamping surface of the jaws on the lathe so they are matched to the run out of the chuck. Make sure to mark them so you always get them bolted back up in the correct position.
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Nice vid, one other way to skin the proverbial cat .
When I get a chance I'll start another thread showing how I do it .
Turing those pistons with open sides and asymmetric skirts is a trend here now! I think one of the next vid's will about squish bands and a fixture I built to handle cylinders that aren't as easy to hold as those nice essentially square Husqvarna 300 series cylinders. For example 562's..and even more relevant Stihl MS660's...
(Think derivative of a bearing puller.. and its pretty universal but still requires an arbor for setup and allignment .. needs testing time before video time though)
Fortunately none of this requires heavy cuts therefore heavy loading on the tooling or fixturing. The bases with their interrupted cut is about the worst case we have to deal with....and why leaving that arbor in is a good Idea when cutting those bases. Although I'm a fan of things like arbor / cutter derivatives of gang tooling and fly cutters, looking to finish developing tools that can handle a wide array of cylinders so I don't have a cabinet devoted to a gazillion different sizes and cylinders. One boring bar. One fixture. A series of arbors of different diameter's. Two chucks. A tail stock drill chuck. A tailstock live chuck. Many cylinders now possible to tweak. That's where I am and hope to prove as a functional idea...over time. Trying to develop a system to support the hobby for the price of a big chainsaw...under 1000 to replicate is the goal.
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Nice vid, one other way to skin the proverbial cat .
When I get a chance I'll start another thread showing how I do it .
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Great video ............. shouldnt be so hard on yourself !
Have to get it done, and you sure did !
More videos please !!!
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depends...
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Do you mod the combustion chamber for the pop up.
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Works very well ! How I do it too !
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I watched part of the video. Pretty good idea. I might try it some time.
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That's a lousy shift! Used to have a 3:30AM until 2:00PM shift. Sucked all the way around, and lack of sleep was a terrible side effect...ended up in the ER twice as collateral damage! Now my shift is much better.... 3:30pm to Midnight... right now assembling our winter "offices"
(https://chainsawrepair.createaforum.com/proxy.php?request=http%3A%2F%2Fwww.forestryforum.com%2Fgallery%2Falbums%2Fuserpics%2F11485%2F20151023_112052.jpg&hash=3926d4fafde9658b15c3ef05589c44c056be0b94)
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31 minutes .......................
i will be watching this tomorrow morning around 05:00 ....... during my first break !!
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Yea..it was cold. Shouldn't have "loose" clothing any where near a lathe.
https://www.youtube.com/watch?v=X2748UHyyGE