Center punched fasteners

BERT · Feb 12, 2021

What is the proper way to remove center punched fasteners (oil pump, crankshaft etc.)? Can the fasteners be reused? Thanks.

kommando · Feb 12, 2021

As long as you are not touching the crank, the cases or the pump you can grind or punch the burr away, never reuse as even grinding/punching away the burr the thread will still be distorted so new fasteners. I never re-punch but use loctite instead.

marshg246 · Feb 12, 2021

kommando said:
As long as you are not touching the crank, the cases or the pump you can grind or punch the burr away, never reuse as even grinding/punching away the burr the thread will still be distorted so new fasteners. I never re-punch but use loctite instead.

Agree.

Also, in most cases if it is a nut that is punched, you can simply remove and replace as the removal will chase the bolt threads and you have done no additional damage. Sometimes the screws in the oil pump have been punched - they need to be cleaned up with a burr or drill first as un-screwing the steel screws from the alloy pump bottom will damage the threads in the pump body bottom.

For the bolts and nuts that hold the crankshaft together, I buy the kit of new parts and replace all the bolts, nuts, and tab washers - expensive, but then you're sure you'll have no problem.

dynodave · Feb 12, 2021

Any center punched components get reused only after tap and die clean up. . I never center punch the hardware.
Depending on location determines loctite grade used on reassembly.

jaydee75 · Feb 12, 2021

Did Norton actually use this technique at the factory? I haven't been deep enough into the engine to see this anywhere.
Jaydee

marshg246 · Feb 12, 2021

jaydee75 said:
Did Norton actually use this technique at the factory? I haven't been deep enough into the engine to see this anywhere.
Jaydee

I have seen no evidence that they did. Engines that I'm fairly sure (not positive) have never been apart have no center punches. One of those was a Combat engine with 2400 miles and the original-type bearings that sat in a pole barn since 1974.

dynodave · Feb 12, 2021

jaydee75 said:
Did Norton actually use this technique

jaydee75 said:
to see this anywhere.

marshg246 said:
I have seen no evidence that they did.

marshg246 said:
Engines that I'm fairly sure (not positive) have never been apart have no center punches.

marshg246 said:
the removal will chase the bolt threads and you have done no additional damage

WOW WOW WOW

What is "this technique" ???????

I've done dozens of both items...
EVERY OEM crankshaft hardware is center punched!
EVERY OEM oil pump hardware is center punched!

BERT · Feb 12, 2021

dynodave said:
WOW WOW WOW

What is "this technique" ???????

I've done dozens of both items...
EVERY OEM crankshaft hardware is center punched!
EVERY OEM oil pump hardware is center punched!

The 72 I'm into has both the crank and oil pump center punched. The backplate on the pump is tapped and there isn't much thread to mess with. Careful drilling and loctite reassembly?

marshg246 · Feb 12, 2021

dynodave said:
WOW WOW WOW

What is "this technique" ???????

Remove the nut and replace (throw the nut away and replace with a new nut). Generally the bolt threads will be OK. If not, of course a thread file, thread chaser, or die will fix.

I have found many engines without any center punches. Of those, I found a few that I think have never been apart with no center punches. About 50% of the oil pumps I've seen have never been center punched.

"EVERY" is an exact term. I've stated nothing exact - stops me from being embarrassed.

dynodave · Feb 12, 2021

BERT said:
drilling

HUH?
reread Post #4 and see if it "comes to you?"
2BA & 5/16 CEI

"Every" is my experience so far...30 + years

BERT · Feb 12, 2021

dynodave said:
HUH?
reread Post #4 and see if it "comes to you?"
2BA & 5/16 CEI

"Every" is my experience so far...30 + years

Thanks for your help.

marshg246 · Feb 12, 2021

dynodave said:
HUH?
reread Post #4 and see if it "comes to you?"
2BA & 5/16 CEI

"Every" is my experience so far...30 + years

I disagreed with Post 4 so I said nothing.

"Any center punched components get reused only after tap and die clean up" is another exact statement that I do not believe to be true/wise. Of course you can get them to screw together but I'm not sure it's always a good idea.

"Depending on location determines loctite grade used on reassembly." I don't agree or disagree with this, but I really don't like it when people use Red Loctite when Blue is plenty and several of the other Loctite versions may or may not have a place in a Norton.

Do understand that your word is many times more respected than mine on this forum but it would be nice to temper your brashness - we're all trying to help others and/or get help ourselves.

BERT · Feb 12, 2021

marshg246 said:
Remove the nut and replace (throw the nut away and replace with a new nut). Generally the bolt threads will be OK. If not, of course a thread file, thread chaser, or die will fix.

I have found many engines without any center punches. Of those, I found a few that I think have never been apart with no center punches. About 50% of the oil pumps I've seen have never been center punched.

"EVERY" is an exact term. I've stated nothing exact - stops me from being embarrassed.

Thank you for your advice.

dynodave · Feb 12, 2021

Years of NHT engines I've looked at and/or worked on 49, 52, 53, 57, 59, 60, 62, 63, 65, 68, 71, 72, 73, 74, 75.
They are not all pointy center punched.
If you look close enough you may see a narrow flat depression on face of the nut where they are punched and there is a small thread deformation.

BERT · Feb 12, 2021

marshg246 said:
Remove the nut and replace (throw the nut away and replace with a new nut). Generally the bolt threads will be OK. If not, of course a thread file, thread chaser, or die will fix.

I have found many engines without any center punches. Of those, I found a few that I think have never been apart with no center punches. About 50% of the oil pumps I've seen have never been center punched.

"EVERY" is an exact term. I've stated nothing exact - stops me from being embarrassed.

Thank you for your advice

dynodave said:
Years of NHT engines I've looked at and/or worked on 49, 52, 53, 57, 59, 60, 62, 63, 65, 68, 71, 72, 73, 74, 75.
They are not all pointy center punched.
If you look close enough you may see a narrow flat depression on face of the nut where they are punched and there is a small thread deformation.

I have never seen fasteners mechanically locked this way(from the end). I have used the method of 3 threads showing and then carefully prick punching the flat of the male thread close to the nut to peen it tight.

dynodave · Feb 13, 2021

From 49 thru 67 is a long time for NHT compared to the short commando era. Two cranks right behind me 53 & 62 have the little face punch style. But the 65 atlas crank looks to be pointy center punched at the thread juncture of the nut/bolt . The bolts don't stick out of the longish nuts.

Deets55 · Feb 15, 2021

Just curious, but is it possible that some of these “punched” nuts are really just manufactured, all metal locking nuts? I have seen them out of the box with dimples on the side and also on the top that act as a self locking feature. I’m not sure if this pre-dates nylon locking nuts, but I have run across a lot of them.

maylar · Feb 15, 2021

Deets55 said:
Just curious, but is it possible that some of these “punched” nuts are really just manufactured, all metal locking nuts? I have seen them out of the box with dimples on the side and also on the top that act as a self locking feature. I’m not sure if this pre-dates nylon locking nuts, but I have run across a lot of them.

And they can be a mother-bear to assemble/disassemble. Recently experienced them on the shear bolts on my snow blower.

concours · Feb 15, 2021

maylar said:
And they can be a mother-bear to assemble/disassemble. Recently experienced them on the shear bolts on my snow blower.

Gen-you-ine Ariens/Honda/Simplicity stuff? Or low rent stuff?
50 years, probably upwards to a hundred shear pins, never a problem.

maylar · Feb 15, 2021

concours said:
Gen-you-ine Ariens/Honda/Simplicity stuff? Or low rent stuff?
50 years, probably upwards to a hundred shear pins, never a problem.

Yup, gen-you-ine Ariens. Not really a problem other than not being able to start the thread with my fingers and judging the torque when tightened.

Center punched fasteners

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