Can I weld this shaft?

S

Spokerider

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Guys,
On my Craftsman 101.07301 the countershaft shaft...….the actual shaft with the 4 flats milled on it [ M6-75 ] has metal worn away. The shaft corners where the two flats meet, are worn from the screw dragging across this corner, when rotating the shaft to tight / loosen the belts. The corner is no longer a sharp corner, but grooved in the shape of the screw end.

Wondering...….is this hardened steel?
Can I just tig the groove to fill it up, and file smooth / back to shape?
Not being sure what the metallurgy of this part is...….this repair may fix it, or make it softer...….hummmm.

Thots please?
 
Weldability depends on what the shaft is made of, and there is no really easy way to check that.
Heat from welding will likely distort the shaft, unless this is at the very end.
If welding you would want to TIG it, so the result is not super hard.
Brazing would be another option and likely safer.
Any of these would remove any heat treat, you can check for hardness using a file.
 
Craftsman lathe...

Think cheap...

Hardened shaft would not have failed as OP described and would have been not needed expense.

Mig weld with high heat to get it done fast.

Repeat spots so short time to reduce stresses then file.

Better if you can file existing and use longer screw or simply epoxy fill.

Minimal power here.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
I wouldn't worry if it is hard unless some newbie made that shaft out of D-2. Usually, they are medium carbon, and TIG welding with normal cooling causes hard, non-machinable spots. Just do a spark test to confirm (Youtube) and sub-critical anneal with a dull red heat (barely visible in subdued light). It will cut.
 
My experience with Atlas/Craftsman parts is that they are soft, low carbon steel. If you are going to weld it, I would recommend something like RG45. You can also make a new one, just use the same size rod and file the flats onto the shaft. They don't have to be perfect, they are there to ensure that the screw doesn't raise a bur and make it difficult to remove the pulleys. Making a new one may be less work than fixing the existing one.
 
It's such a small area I don't really see any problem. I'd have a hard time counting the number of times I've made weld repairs (generally mig) and ground or filed to shape with no issues. Mike
 
To determine what the countershaft material is, call Clausing and ask. If the parts are still on the active list, they will not send you the drawing but should tell you what the drawing says that the one that you want to fix is made of. The M6-75 may be on the obsolete list in which case they should be happy to send you a PDF or TIF of the drawing.
 
If it were me, I'd just weld it with ER70S6 and then clean it up on the lathe. It may or may not warp. If it does, straighten it on a press with v-blocks until it's true. If any of that fails utterly, then knock off a replacement out of an old piece of gas pipe.
 
Thank you guys for the input.
I'll just tig weld it, and hand file the flats again. This is not a critical component, and based upon what you guys are saying, it's not hardened tool steel, or it would not have galled to begin with. Good point.
 
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