parts saw or worth messing around with?

[flatsfisher]

next challenge. this was obvious when I bought the saw (the screw was holding the small piece on) but for 40 bucks I figured I would tig it back together. was getting ready to do that the other day but the lightness of this rather large base made me pause. I wire wheeled the end of it and dipped it in white vinegar and crap. its magnesium. now that's kinda cool and I know cast magnesium can be tigged but it requires magnesium filler rod and to get the right rod you really are supposed to know what alloy of magnesium you are welding. also, my tig skills are just barely adequate with aluminum.

any ideas on a repair? or anyone have a used one cheap? from my research this design was exclusive to the SP70, SP81 (same part numbers) and maybe the SP60 (looks the same in pics except for a small threaded spool which could be cut off).

I have a couple of ideas but won't really look right when done. I'm kind of excited about this project and don't want it to look cheesy.

thanks.

 

[Jasonrkba]

Broken magnesium is such a pain to work with. I have a feeling 3D printers will save a lot of old saws in the future.

 

[flatsfisher]

I talked to the only 2 welders in town who do tig (small rural area). neither had ever welded magnesium. one of them called his supplier (Airgas) and magnesium filler rod runs 99.00 to 150.00 per lb and he would have to buy 3 lbs. so I have a new plan.

 

[heimannm]

The piston is fit with pins to locate the ring end gaps so deduct that from the measured gap to come up with the actual end gaps. In the bore like that it will often be over 0.070". If I recall the pins are around 0.045"

Mark

 

[scottr]

I talked to the only 2 welders in town who do tig (small rural area). neither had ever welded magnesium. one of them called his supplier (Airgas) and magnesium filler rod runs 99.00 to 150.00 per lb and he would have to buy 3 lbs. so I have a new plan.

Have you tried calling a tech school or jr college to find a magnesium welder ?
Or maybe it's time for a trip to the big city .

 

[flatsfisher]

The piston is fit with pins to locate the ring end gaps so deduct that from the measured gap to come up with the actual end gaps. In the bore like that it will often be over 0.070". If I recall the pins are around 0.045"

Mark

that's interesting. I didn't snap to the fact that the rings aren't scalloped at the pins like modern rings.

in the service manual it says "from .051 to .066 on 4.3 cu in motors with pinned rings. my end gap is .0742.

 

[flatsfisher]

I made this today for my broken magnesium base plate. best I could do. would be epoxied on and maybe a roll pin or something for good measure. but it looks far from correct so will likely just get another base plate.

 

[flatsfisher]

making sure the height is correct.

 

[Jasonrkba]

You are a pretty crafty guy. It may be stronger than before if you can keep it snugged down so it doesn't come loose.

 

[flatsfisher]

it would work and is def stronger, but I did a poor job of copying the original part. the curve is not the same. if I was going to do this fix, I would make another one and do a better job. I would need to cut the original yellow vertical piece shorter and extend the top half of my replacement part. seems like I always do everything twice. getting a new undamaged one is a better idea.

 

[Jasonrkba]

The journey is the fun part.

 

[Junk Saw Collector]

@flatsfisher any updates? I know I’m late to the party on this build, but I’m very interested.

 

[flatsfisher]

I think I moved the build to the main MAC thread a long time ago but here are some pics of the finished project.

 

[flatsfisher]

 

[Junk Saw Collector]

Damn! That’s beautiful! Good work. Thanks for posting some pics and a video. I guess I missed it in the main McCulloch thread.

 

[flatsfisher]

thanks!

 

[Maintenance supervisor]

How much of that yellow paint do you have left?

 

[flatsfisher]

How much of that yellow paint do you have left?

only had a pint so not much left. the 1st pint they mixed for me was too light (but about matches the stock 10-10 I have. SP70 was a darker yellow. I may add what I have left of the dark to what I have left of the lighter color. I accidentally used the lighter color when I painted the 10-10S, but I like it. the re-painted 10-10S and the original paint 10-10 I have are pretty close in color.

 

[flatsfisher]

 

[Junk Saw Collector]

only had a pint so not much left. the 1st pint they mixed for me was too light (but about matches the stock 10-10 I have. SP70 was a darker yellow. I may add what I have left of the dark to what I have left of the lighter color. I accidentally used the lighter color when I painted the 10-10S, but I like it. the re-painted 10-10S and the original paint 10-10 I have are pretty close in color.
View attachment 1059683View attachment 1059684

Good lord @flatsfisher! That’s the prettiest PM 10-10S I’ve ever seen! I guess I need to step up my game while I’m restoring mine. I appreciate the motivation.