Spur sprockets - Worn vs Worn out

[MartDalb]

Heya all

So...taking a look at some of my Stihl "spur sprockets", wondering when do you call it worn, and when is it worn-out?

I'd say, this one is worn, but still has some use in it.
What is your opinion?
See pictures.

 

[HarleyT]

Replace them when you get a new chain or two.

 

[user 122190]

Time to replace. Look into switching to a rim sprocket. More durable, less expensive to replace so the decision to replace comes fast. Part of good maintenance is tossing out warn components before they damage downstream parts.

 

[thomasinvancouver]

Two chains = new sprocket. Switch to a rim.

 

[MartDalb]

Indeed the next will be a rim sprocket on this 029.

Thanks for the replies everyone!

 

[Brushwacker]

If you have stretched out chains u want to use up , use that sprocket for them only. The stretched chains will wear a new sprocket prematurely like as that worn sprocket would stretch new chains.

 

[SawTrash]

If you have stretched out chains u want to use up , use that sprocket for them only. The stretched chains will wear a new sprocket prematurely like as that worn sprocket would stretch new chains.

Have often wondered if it would be worthwhile running a small arc weld over the worn groove in a spur sprocket then shaping it flush with my Dremel.

Has anybody done this.? ?

Always seems a waste just chucking a spur sprocket into the scrap metal bin when only a small bit is worn.

 

[user 122190]

Have often wondered if it would be worthwhile running a small arc weld over the worn groove in a spur sprocket then shaping it flush with my Dremel.

Has anybody done this.? ?

Always seems a waste just chucking a spur sprocket into the scrap metal bin when only a small bit is worn.

I have learned that it is rarely worth it to push the limits of equipment and parts. Exception is in the chains, that get better and better as you reduce the cutter to the very last bit. Just replace the sprocket and go cut some wood.

 

[rupedoggy]

Have often wondered if it would be worthwhile running a small arc weld over the worn groove in a spur sprocket then shaping it flush with my Dremel.

Has anybody done this.? ?

Always seems a waste just chucking a spur sprocket into the scrap metal bin when only a small bit is worn.

All right a conservative fellow. That's right, get all the use out of that $6 part you can!. I think you should use them until they break into two pieces and THEN weld them. You might even experiment by turning one piece around to get some fresh metal.
BTW do you reuse condoms by using shoe goo after cleaning, to repair holes?

 

[old guy]

Have often wondered if it would be worthwhile running a small arc weld over the worn groove in a spur sprocket then shaping it flush with my Dremel.

Has anybody done this.? ?

Always seems a waste just chucking a spur sprocket into the scrap metal bin when only a small bit is worn.

I did that once, it worked, don't remember what it was on, something old.

 

[cookies]

you will change the hardness of the spur if you weld on it, possibly warp the drum.

 

[Philbert]

Have often wondered if it would be worthwhile running a small arc weld over the worn groove in a spur sprocket then shaping it flush with my Dremel.

Seems like a lot of work, but if you have the time to try it, people have spent more time on more trivial things.

Might be something to think about if it was a no longer available part for an older saw.

Some of the sprocket portions may be cast; some may be made from sintered metal. So play with some scrap ones that you don’t care about before trying it on one you do.

And let us know!


Philbert

 

[HarleyT]

Shoe goo and condoms paint an interesting picture.

 

[cookies]

so do you need to put on the condom to perform these repairs properly? asking for a neighbor

All right a conservative fellow. That's right, get all the use out of that $6 part you can!. I think you should use them until they break into two pieces and THEN weld them. You might even experiment by turning one piece around to get some fresh metal.
BTW do you reuse condoms by using shoe goo after cleaning, to repair holes?

 

[MartDalb]

hehe loving the derail!

Great input, even the condom part!

 

[SawTrash]

Seems like a lot of work, but if you have the time to try it, people have spent more time on more trivial things.

Might be something to think about if it was a no longer available part for an older saw.

Some of the sprocket portions may be cast; some may be made from sintered metal. So play with some scrap ones that you don’t care about before trying it on one you do.

And let us know!


Philbert

There are 4 Stihl dealers within an hour's drive and the one I shop at sold me a new spur sprocket and the caged roller bearing for my MS170 for the equivalent of US $ 40. Yep, there are cheaper aftermarket items available but probably made of cheese - I prefer to buy genuine.

So, below there's a pic of the worn one, and many would say it's got more work left but a lifetime of mucking around with motorcycles has taught me not to put a new chain on worn sprockets, and my hand filed chain was cactus.

I arc/stick welded it up with some 2.5mm 6013 which is the smallest I had in the shed, then ground it down with a burr in the Dremel. Pic two.

The welding distorted the bore a little so it needed a bit of honing and I mounted the sprocket with the old caged bearing, did a tank of firewood cutting with a new chain.

Inspecting the repaired sprocket after cutting and it was evident my hand grinding was a bit rough and ready in that a couple of the teeth's renewed surfaces had a bit more wear than the others.

All in all it was a worthwhile exercise. Next time it will be welded with a harder rod material (maybe ask a mate who can Mig/Tig, whatever) and ground down with a more accurate indexing method to get all six teeth equal.

 

[46 Poulan]

Some guys up north like to soak them in lemon juice or is it brake fluid????---My mistake--That was for carb gaskets and diaphragms only-makes them like new-soft yet firm and very pliable!!!!Fried okra will restore the worn sprockets......................

 

[Philbert]

All in all it was a worthwhile exercise

Nice. I’d bet that in some parts of the world that is standard practice.

Philbert

 

[Mad Professor]

you will change the hardness of the spur if you weld on it, possibly warp the drum.

Welds are generally harder than the base metal

 

[Mad Professor]

If you have stretched out chains u want to use up , use that sprocket for them only. The stretched chains will wear a new sprocket prematurely like as that worn sprocket would stretch new chains.

Yup, just like bicycles and motorcycle chain. Replace the whole set.

For saws you can rotate 3-4 chains on same rim to keep wear even.