Polygon Crankpin technology for Twin Cam Flywheels
#21
Long a go in the 60s in shop 101, the wrist pin of a crank was the pin that goes thru the big end of the connecting rod. If you google wrist pin now since you made me, it still does. Realize Harleys crank lobes are usually called wheels by me since they look more fly wheel like them lobes. My interest came anout this simply on a designer and machinest point locking and indexing the crank to prevent sissoring. Terry and I sent emails back and forth and he like you say is one cool dude to take his time in going into detail.
#22
not used so much in Auto industry but in heavy fixed plant.
often drill and tap a thread and use a grub screw, loctited in..
#23
#24
#25
Allen Socket head cap screw.. (usually grade 8 here in the US)
Allen set screw = (grub screw in UK) Quite often in the US on a fan in a heating system, the grub screw will have a square on it for those who do not have a set of Allen wrenches or maybe since that stuff gets all rusty and you can get it out if you are lucky with Vicegrip pliers.
Allen set screw = (grub screw in UK) Quite often in the US on a fan in a heating system, the grub screw will have a square on it for those who do not have a set of Allen wrenches or maybe since that stuff gets all rusty and you can get it out if you are lucky with Vicegrip pliers.
Last edited by Jackie Paper; 02-08-2017 at 03:42 PM.
#26
The polygon shape you see in the wheel is the wrist pin. It is totally ground and basically is a press fit into the crank wheel of the crankshaft shouldered on the inside. Being so huge, it is only about .001 press. That smaller plug with company logo is a press fit plug of about .001 press interference fit into a blind hole in the wrist pin on the front face of the wheel. It tends to increase the overall press and retains the wrist pin while the polygon which is already pressed in, does the driving.
The original test bed was proven out in the owners 120 Harley.
The original test bed was proven out in the owners 120 Harley.
#27
What's a few thousands of an inch among friends?? HA.....
Actually, what I posted was from an email from him but sure it could have been updated since he is the racer and the technology is coming from the actual company that produces the the part. What I posted was from that email.
Don't have his email on my laptop and out of the country but how it was explained to me in email was too much press could result in a loss of dimensional accuracy do to shear rather then compression and could index the crank. The shape does the drive and of course the press holds it together somewhat. However, the finial squash is that oversize round pin that is pressed in the end that you see their signature engraved in. So, maybe what you are quoting is the total.
I was in the machine shop world for 46 years and .009 is a lot of press.
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Big J1 (02-19-2017)
#28
Crank looks good-only a handful actually out there running them at this time.
Wanna pay big bucks to be one of the first, with no results history of R&D/T&T/current/former users? Not me.
Run S&S and be done with it-move on to other areas of the motor and use the extra cash to make HP. I've run 200 HP on their standard crank/rods and over 225 N/A on S&S prostock crank/rods. NO ISSUES. Should be enough for most anyone posting here.
Wanna pay big bucks to be one of the first, with no results history of R&D/T&T/current/former users? Not me.
Run S&S and be done with it-move on to other areas of the motor and use the extra cash to make HP. I've run 200 HP on their standard crank/rods and over 225 N/A on S&S prostock crank/rods. NO ISSUES. Should be enough for most anyone posting here.
The following users liked this post:
msocko3 (02-11-2017)
#29
What's a few thousands of an inch among friends?? HA.....
Actually, what I posted was from an email from him but sure it could have been updated since he is the racer and the technology is coming from the actual company that produces the the part. What I posted was from that email.
Don't have his email on my laptop and out of the country but how it was explained to me in email was too much press could result in a loss of dimensional accuracy do to shear rather then compression and could index the crank. The shape does the drive and of course the press holds it together somewhat. However, the finial squash is that oversize round pin that is pressed in the end that you see their signature engraved in. So, I was in the machine shop world for 46 years and .009 is a lot of press.maybe what you are quoting is the total.
Actually, what I posted was from an email from him but sure it could have been updated since he is the racer and the technology is coming from the actual company that produces the the part. What I posted was from that email.
Don't have his email on my laptop and out of the country but how it was explained to me in email was too much press could result in a loss of dimensional accuracy do to shear rather then compression and could index the crank. The shape does the drive and of course the press holds it together somewhat. However, the finial squash is that oversize round pin that is pressed in the end that you see their signature engraved in. So, I was in the machine shop world for 46 years and .009 is a lot of press.maybe what you are quoting is the total.
Hi Jerry.
I thought I would send you a private message to let you know that if you'd like to call me feel free. But I did want to let you know that the polygon is pressed in with a .009" interference fit !
#30
Polygon crankpin
The polygon shape you see in the wheel is the wrist pin. It is totally ground and basically is a press fit into the crank wheel of the crankshaft shouldered on the inside. Being so huge, it is only about .001 press. That smaller plug with company logo is a press fit plug of about .001 press interference fit into a blind hole in the wrist pin on the front face of the wheel. It tends to increase the overall press and retains the wrist pin while the polygon which is already pressed in, does the driving.
The original test bed was proven out in the owners 120 Harley.
The original test bed was proven out in the owners 120 Harley.