Have a air coooled engine whose crankshaft is worn w/slight ridge. The engine makes approximately 37 HP and spins up to 7K. Shaft has a keyway and left-handed nut which secures a attached helical cut gear. In order to deal with the damaged shaft, I'm looking at retaining compounds although not sure if they will handle this HP, vibration, and temps up to 350 F. There is quite of lot of shear force and vibration at the shaft. There seems to be a lot of variables when it come to RC's, do any of you have any experience with this?
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Retaining Compound
- Thread starter motoretro
- Start date
RPH
Well-known member
Loctite has plenty of products that can cover the temperature range. Amount of gap between surfaces will be the determining factor.
jeepinerdeep
Well-known member
Loctite has plenty of products that can cover the temperature range. Amount of gap between surfaces will be the determining factor.
This. Figure out what your fit is first.
It's not a bandaid cure. It's intended for fits that are slightly off ideal.
The fit and temps are not really the issue, I know I can get a product that will fill the gap and handle the temps the engine reaches. It's whether the product will handle shear forces from a high torque, 37 HP engine known for it's vibration. When I look at the TDS of different products, I'm concerned about the advertised shear forces and every aspect that effects these shear forces. Sure temps come into play as does age of bond, type of materials bonded, chemicals that touch the bond, etc. It seems like there's a ceiling, shear baseline and everything else reduces this figure. Once you add it all up, is there enough bond strength left to hold together?
Can you use a shafted saver?
https://www.timken.com/products/timken-mechanical-power-transmission-products/seals/redi-sleeves/
https://www.timken.com/products/timken-mechanical-power-transmission-products/seals/redi-sleeves/
I hit the folks at Loc-tite with a lot of questions, they responded with patience and knowledge. Based on our discussions, I've decided to go with their #638 product. I'm still waiting on parts, hopefully I get them soon and re-assemble things before cold weather kicks in.
The other company I requested information from, never responded.
The other company I requested information from, never responded.
Rocksett is a ceramic cement (not a contact cement). You have plenty of working time. Ready to use as is (no mixing). Low Shrinkage.
It is best to have component parts bone dry. Use rubbing alcohol to remove any lubricants from parts.
Bonding of parts can be made without the use of heat. However for best results the joined parts should be heated to 175 degrees Fahrenheit for approximately 15 minutes. Use a hair dryer or a similar heat source that won't damage finish of parts.
Rocksett tensile strength is approximately 250 pounds per square inch. The shear strength is 450 pounds per square inch, more than sufficient for most purposes.
The main purpose of Rocksett is to keep assemblies from vibrating and dislodging under extreme temperatures. Rocksett can withstand incredible temperatures from -292 degrees Fahrenheit up to and beyond +1500 degrees Fahrenheit.
It is best to have component parts bone dry. Use rubbing alcohol to remove any lubricants from parts.
Bonding of parts can be made without the use of heat. However for best results the joined parts should be heated to 175 degrees Fahrenheit for approximately 15 minutes. Use a hair dryer or a similar heat source that won't damage finish of parts.
Rocksett tensile strength is approximately 250 pounds per square inch. The shear strength is 450 pounds per square inch, more than sufficient for most purposes.
The main purpose of Rocksett is to keep assemblies from vibrating and dislodging under extreme temperatures. Rocksett can withstand incredible temperatures from -292 degrees Fahrenheit up to and beyond +1500 degrees Fahrenheit.
joe49
Well-known member
Have shaft knurled and cut to size or metalize and cut to size.
Rocksett is a ceramic cement (not a contact cement). You have plenty of working time. Ready to use as is (no mixing). Low Shrinkage.
It is best to have component parts bone dry. Use rubbing alcohol to remove any lubricants from parts.
Bonding of parts can be made without the use of heat. However for best results the joined parts should be heated to 175 degrees Fahrenheit for approximately 15 minutes. Use a hair dryer or a similar heat source that won't damage finish of parts.
Rocksett tensile strength is approximately 250 pounds per square inch. The shear strength is 450 pounds per square inch, more than sufficient for most purposes.
The main purpose of Rocksett is to keep assemblies from vibrating and dislodging under extreme temperatures. Rocksett can withstand incredible temperatures from -292 degrees Fahrenheit up to and beyond +1500 degrees Fahrenheit.
Sounds like good product, unfortunately the worn step in the shaft's surface requires a product that can fill & level things out. I feel the best product for doing this is a retaining compound. I will keep the Rocksett in mind for some other projects though.
Have shaft knurled and cut to size or metalize and cut to size.
Years ago when the automotive plants in my area had support from local machine shops, that might have been possible. 98% of the small job shops have shut down along with the plants. The rest don't care for small jobs. It's not worth their time. This would have also required a full disassembly, gear box and engine. The engine has 26K on it and to tear it down to that extent, it would have been crazy not to rebuild the engine at that time. Bike is only worth about 2K, price of a new crank is $780. My thinking on this is if I can't fix it inexpensively, I would just part the bike out.
joe49
Well-known member
MacGyver time. Knurl in place if the shaft can be rotated with out the gear on. Make a simple fixture to hold knurl tool to bolts in case.
You could also use a automatic center punch to raise metal in a pattern to work similar to knurling. Using the auto punch will keep the punch marks uniform.
You could add Loctite to either of these ideas as well.
You could also use a automatic center punch to raise metal in a pattern to work similar to knurling. Using the auto punch will keep the punch marks uniform.
You could add Loctite to either of these ideas as well.
ez-duzit
Well-known member
...98% of the small job shops have shut... The rest don't care for small jobs. It's not worth their time. This would have also required a full disassembly, gear box and engine. The engine has 26K on it and to tear it down to that extent, it would have been crazy not to rebuild the engine at that time. Bike is only worth about 2K, price of a new crank is $780...
Hearing only excuses to rationalize doing a Mickey Mouse job. If you believe that you can't...you're right.
With the economy shutdown there are plenty of qualified people looking for work. You don't need a brand new $780 crank or a $5 tube of acumpucky to fix this properly. You just need the will to do it.
Hearing only excuses to rationalize doing a Mickey Mouse job. If you believe that you can't...you're right.
With the economy shutdown there are plenty of qualified people looking for work. You don't need a brand new $780 crank or a $5 tube of acumpucky to fix this properly. You just need the will to do it.
Enlighten me, how do you do this properly?
ez-duzit
Well-known member
Take the crank out and bring it to an automotive machine shop.
Lookin4'67Galaxieconv
Well-known member
Gotcha!
FYI, was going to send you a private message but you don't seem to have that enabled on your profile.
Monza Harry
Well-known member
Knurling may be accomplished in place with a hand knurling tool. Similar to a tube cutter with knurls instead of rollers and a a pizza cutter wheel, here's a link for reference:https://www.mscdirect.com/browse/tn...ls/Knurl-Holders/Hand-Knurlers?navid=12105917 Then find some plain wheels [ball bearings of similar ID and OD, may be challenging] to replace the knurls and swage to required dia. using the same tool, "creep up" on it with small increases in pressure as you turn the tool [or the crank if you have to, I hope not]. This way no further mat'l would be removed just pushed around to maintain maximum contact surface area and strength. Harry
P.S. You will have to add a key, fitted to make the shaft round though, probably will not work, I just re-read the first post (it has been a while since I read this and had forgotten about the key way). Food for thought on other repairs. Sorry for the side trip!
P.S.S. Those are spendy little tools I made one in Grade ten shop class a million years ago, I would never have thought they would sell for $600 US Sorry for a complete waste of your time!
P.S. You will have to add a key, fitted to make the shaft round though, probably will not work, I just re-read the first post (it has been a while since I read this and had forgotten about the key way). Food for thought on other repairs. Sorry for the side trip!
P.S.S. Those are spendy little tools I made one in Grade ten shop class a million years ago, I would never have thought they would sell for $600 US Sorry for a complete waste of your time!
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Knurling may be accomplished in place with a hand knurling tool. Similar to a tube cutter with knurls instead of rollers and a a pizza cutter wheel, here's a link for reference:https://www.mscdirect.com/browse/tn...ls/Knurl-Holders/Hand-Knurlers?navid=12105917 Then find some plain wheels [ball bearings of similar ID and OD, may be challenging] to replace the knurls and swage to required dia. using the same tool, "creep up" on it with small increases in pressure as you turn the tool [or the crank if you have to, I hope not]. This way no further mat'l would be removed just pushed around to maintain maximum contact surface area and strength. Harry
P.S. You will have to add a key, fitted to make the shaft round though, probably will not work, I just re-read the first post (it has been a while since I read this and had forgotten about the key way). Food for thought on other repairs. Sorry for the side trip!
P.S.S. Those are spendy little tools I made one in Grade ten shop class a million years ago, I would never have thought they would sell for $600 US Sorry for a complete waste of your time!
Certainly not a waste of time, while I was familiar with knurling, I've never seen it applied to a crankshaft nose, Thanks, I'll check out the link.
Parts are slow coming, I received some of the parts needed to button the engine up although gear was back ordered. Hopefully it gets here soon. I did get the key and once gear arrives, I can determine the fit and amount of play.
Thanks, G.
larry4406
Well-known member
What kind of bike (motorcycle?) engine?
What kind of bike (motorcycle?) engine?
Suzuki DR650 w/ 26K
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