Round 2 (with better pictures) sheared MS440 Crank

[farmguywithasaw]

Regular good quality hss bit slow slow speed with rapid tap oil should drill it. When you spin the bit too fast you overheat it a wreck the cutting edge. Also the heat will temper the steel being cut

 

[Alphadelta]

Regular good quality hss bit slow slow speed with rapid tap oil should drill it. When you spin the bit too fast you overheat it a wreck the cutting edge. Also the heat will temper the steel being cut

What rpm are we talking?

My drill press can’t do slower then like 500.


Sent from my iPhone using Tapatalk

 

[frank_]

i,ve drilled with a masonry bit a few times, you have to sharpen it like you do an hss one tho
but a tap is gonna suffer the same fate as your drill did tho surely ?

 

[Alphadelta]

i,ve drilled with a masonry bit a few times, you have to sharpen it like you do an hss one tho
but a tap is gonna suffer the same fate as your drill did tho surely ?

My thoughts as well.

However many people have successfully pulled this off, so unless they are buying $200 carbide taps.
I would imagine this is more about technique and less of tools per say.

I do think part of my error is the speed of my drill press. But who knows for sure.

 

[frank_]

My thoughts as well.

However many people have successfully pulled this off, so unless they are buying $200 carbide taps.
I would imagine this is more about technique and less of tools per say.

I do think part of my error is the speed of my drill press. But who knows for sure.

praps if you oversize the drill slightly ? so that the tap is cutting a minimal thread
and tap pretty deep + some red threadlock for extra strength

 

[Alphadelta]

praps if you oversize the drill slightly ? so that the tap is cutting a minimal thread
and tap pretty deep + some red threadlock for extra strength

Good idea. I’ll have to consider that. But.
First step is getting a drill bit to actually cut. My cobalt set isn’t doing anything.


Sent from my iPhone using Tapatalk

 

[KarlD]

IMHO 9 of the 10 people who have said they have done this are talking BS.
Only option I can see without spending stupid time and money on the fix is a replacement crank.
Or sell the saw as is, lesson learned and buy a new one.

 

[Fatherwheels]

IMHO 9 of the 10 people who have said they have done this are talking BS.
Only option I can see without spending stupid time and money on the fix is a replacement crank.
Or sell the saw as is, lesson learned and buy a new one.

If it’s that hard, then a carbide cutter is about the best option,
this will cost you, as above get a secondhand crank, drilling tapping your old crank
is a job for a pro, it needs to be done right or not at all, and cost will dictate the best
route to take in any event.

 

[lone wolf]

Just buy a used crank from a member on here!

 

[Alphadelta]

Just buy a used crank from a member on here!

That’s the plan actually. Just got in touch with another member.

But I do want to give some advice to people. And it’s uniformed so keep this in mind.

I could not drill through the metal with cobalt. Which surprised me. So I went and bought this.

That is a multi-material carbide drill bit from Home Depot. $5.

It cuts well. About anything. Best I can tell the sudden twisting of the bolt hardened the metal even further or they heat treat the threads. Either way.

Once this chewed that out. And got beneath that. Cobalt is working fine. Cutting exactly how you expect.

Hopefully that helps someone, somewhere at some point.


Sent from my iPhone using Tapatalk

 

[Fatherwheels]

That’s the plan actually. Just got in touch with another member.

But I do want to give some advice to people. And it’s uniformed so keep this in mind.

I could not drill through the metal with cobalt. Which surprised me. So I went and bought this.

That is a multi-material carbide drill bit from Home Depot. $5.

It cuts well. About anything. Best I can tell the sudden twisting of the bolt hardened the metal even further or they heat treat the threads. Either way.

Once this chewed that out. And got beneath that. Cobalt is working fine. Cutting exactly how you expect.

Hopefully that helps someone, somewhere at some point.


Sent from my iPhone using Tapatalk

I would take great care those very hard cuttings / swaf
and pieces of carbon don’t end up in around the bearing,
I would have put a coating of silicon on there before starting to drill,
and taped on a few layers of cooking foil shaped up to catch the filings.

 

[Alphadelta]

I would take great care those very hard cuttings / swaf
and pieces of carbon don’t end up in around the bearing,
I would have put a coating of silicon on there before starting to drill,
and taped on a few layers of cooking foil shaped up to catch the filings.

I appreciate that advice! However I relented.

I kept dulling bits. I couldn’t keep the hole centered so I gave up. The saw is split, and parts clean. Just waiting on a new OEM crank, bearings and seals.

Also splitting this crank was surprising easy with nothing more that a heat gun.

I will post more once I get the parts, and begin reassembly.

Thanks everyone for the advice on drilling vs replacing.

While I think drilling is possible, and economical repair for those who either don’t want to or don’t know how to replace the crank, bearings and seals; it was out my home shops ability and the tools I had on hand.

If you choose to drill, use a drill press, buy high quality cobalt, or preferably carbide twist drills. Go slow, remember carbide hates heat shock. So either flood it or run it dry. M6 is about the biggest I think is appropriate or you run the risk of eating into the key seat. They sell automotive studs that go from M6xM8. Not a bad option, just be careful and for the love of everything holy. Go slow!

Again more to come in the coming weeks as parts come in.


Sent from my iPhone using Tapatalk

 

[RED-85-Z51]

I gave up on drilling. Without an end mill and 3 axis fixture, drilling by hand or with a press is a toss up. Last week when the exhaust stud twisted off in a customers saw i didnt want even attempt to drill it..not worth it to me. New short block and its fixed right.

Sent from my LM-G820 using Tapatalk

 

[DougMN]

Was that a Chicago pnumatic or ingersal rand? One to many uga dugas.

South main auto.

 

[Fatherwheels]

I appreciate that advice! However I relented.

I kept dulling bits. I couldn’t keep the hole centered so I gave up. The saw is split, and parts clean. Just waiting on a new OEM crank, bearings and seals.

Also splitting this crank was surprising easy with nothing more that a heat gun.

I will post more once I get the parts, and begin reassembly.

Thanks everyone for the advice on drilling vs replacing.

While I think drilling is possible, and economical repair for those who either don’t want to or don’t know how to replace the crank, bearings and seals; it was out my home shops ability and the tools I had on hand.

If you choose to drill, use a drill press, buy high quality cobalt, or preferably carbide twist drills. Go slow, remember carbide hates heat shock. So either flood it or run it dry. M6 is about the biggest I think is appropriate or you run the risk of eating into the key seat. They sell automotive studs that go from M6xM8. Not a bad option, just be careful and for the love of everything holy. Go slow!

Again more to come in the coming weeks as parts come in.


Sent from my iPhone using Tapatalk

You will be happy with the new parts, use a torque wrench on the new one,
I have no idea what Stihl recommends for that nut, maybe someone who works on them will.

A machine / engineering shop would be the place to have the old shaft worked on.
Thats what I meant when I said face up the shaft, so end cutter could drill straight
into it without being forced off centre.
You could use a drill press, but you would spend too much time making a jig to hold
the shaft true to the cutter, a very difficult task, better of getting it done with people
who already have the tools.

 

[Alphadelta]

You will be happy with the new parts, use a torque wrench on the new one,
I have no idea what Stihl recommends for that nut, maybe someone who works on them will.

A machine / engineering shop would be the place to have the old shaft worked on.
Thats what I meant when I said face up the shaft, so end cutter could drill straight
into it without being forced off centre.
You could use a drill press, but you would spend too much time making a jig to hold
the shaft true to the cutter, a very difficult task, better of getting it done with people
who already have the tools.

Absolutely. A mill would of been. Great to say the least.

I’m going to use a torque wrench. I think I read something like 32ft-lbs?


Sent from my iPhone using Tapatalk

 

[lone wolf]

You will be happy with the new parts, use a torque wrench on the new one,
I have no idea what Stihl recommends for that nut, maybe someone who works on them will.

A machine / engineering shop would be the place to have the old shaft worked on.
Thats what I meant when I said face up the shaft, so end cutter could drill straight
into it without being forced off centre.
You could use a drill press, but you would spend too much time making a jig to hold
the shaft true to the cutter, a very difficult task, better of getting it done with people
who already have the tools.

33 NM flywheel nut torque.

 

[Alphadelta]

33 NM flywheel nut torque.

Perfect thank you kindly.


Sent from my iPhone using Tapatalk

 

[lone wolf]

Perfect thank you kindly.


Sent from my iPhone using Tapatalk

Sent a pm with a shop manual just now go look.

 

[OddSawz]

Absolutely. A mill would of been. Great to say the least.

I’m going to use a torque wrench. I think I read something like 32ft-lbs?


Sent from my iPhone using Tapatalk

33nm
or
24.3 ft-lbs