Knurling a bolt?

[DickE]

As I've replaced a few Remington bolts on 700's just to get tighter clearances, I got thinking of a way besides sleeving the bolt, or Borden bumps, and the like. Why won't knurling the bolt body work? The knurling process does expand the metal somewhat in the process, getting just the thousands that I'm looking for. Besides adding a unique look to the bolt its self. Any pros or cons? I think it would work very well.

 

[boltfluter]

To displace the bolt body that much, I would be afraid of the amount of pressure needed. Based on what I have seen fluting bolts, many are more oblong than round. Just something to consider. IMHO.

Regards,
Paul

www.boltfluting.com

 

[butchlambert]

Listen to Paul.

 

[Preacher]

Listen to Butch 'O)

 

[bigwoodsman]

i don,t think it would be a good idea to put knurling on a bolt body to make for a tighter tolerance. raising the diameter of any material done with a knurling tool doesn,t come out to be very concentric at all,besides who would want to scrub out all those small pockets of crude knurling should be done for what it was designed to do and that is making a limited slip surface not trying to create a larger diameter


Jeff

 

[NateHaler]

Are you suggesting that knurling would achieve the same effect as peening? I assumed that knurling was the removal of metal, vs. changing the surface via impact. Who knew.... :-[

 

[butchlambert]

Knurling doesn't remove metal.

 

[JRS]

Are you suggesting that knurling would achieve the same effect as peening? I assumed that knurling was the removal of metal, vs. changing the surface via impact. Who knew.... :-[

Knurling actually displaces the material.

 

[butchlambert]

JRS, You are right. It just moves it around.

 

[DickE]

How about knurling valve guides or piston skirts in engines to tighten up old tolerances. Granted this is not a long term fix for an engine, but how many times does a bolt cycle in a lifetime as compared to a piston or a valve. Not trying to start an argument as I respect the opinions of the ones who have replied. Just would like further discussion.

 

[Lapua40X]

How about knurling valve guides or piston skirts in engines to tighten up old tolerances. Granted this is not a long term fix for an engine, but how many times does a bolt cycle in a lifetime as compared to a piston or a valve. Not trying to start an argument as I respect the opinions of the ones who have replied. Just would like further discussion.

In my experience, knurling of pistons and valve guides is generally used more for lubricant retention on their surfaces and to eliminate or minimize piston slap to some degree. Inasmuch as the rings are the primary mechanical seal between the piston and the cylinder walls, knurling of pistons to provide closer tolerances would make little difference IMO. But my experience in that department run way back to the late 40's and early to mid 50's so there may be some more modern applications that I'm unfamiliar with. :

 

[butchlambert]

Dick,
Being in the business, you will find nobody doing it anymore. Most of our late engines take 30 hrs. to pull, tear down, and replace. Nobody would spend that kind of time and money and knurl guides and piston skirts.

 

[paperpuncher]

OK you guys got me thinking. Anybody have an idea on how one might displace material or move it around in a predictable way. Could one for example take a bolt and forge it to displace enough metal to form bumps that could tighten the bolt to raceway clearance? Would this be likely to compromise the bolt?

 

[LHSmith]

Why make things harder than they have to be......I watched my smith sleeve (2 intermittent pads) the back -end of several Remington bolts. Mine work great. It's not rocket science.

 

[STS]

I've sleeved a bunch of bolts to tighten up clearances and as LH said it isn't rocket surgery. I have never kept track of the time it takes to do one but I doubt it takes me over an hour and a half if I have the sleeves in hand. Like many other jobs there are a few tricks that you learn along the way that make things work really well.

 

[X Ring Accuracy]

Not to start any pissin match, but valve guides that are knurled, are done so to achieve a specified tolerance. In practice, you over knurl it and run a reamer down the guide for a nearly new guide. It is not meant to retain lubrication on the valve stem. The valve seal keeps lube from getting to it.

 

[DickE]

Ok. So we can agree that back in the 50's and 60's mechanics did knurl valve guides and piston skirts. I have talked with mechanics locally that said they used to do a lot of that then. I agree in todays world this is really no longer an option. Too time consuming for a mechanic that you are paying $90-$120 an hour for.
Knurling puts dents in the metal and raises the metal around the dent, much like striking a punch on metal and around the punch mark, the metal is raised. I have done spindles on trailers and agricultural implements, where the bearing surface has worn, and knurled the surface and after that the bearing fits tight again.
On a typical Remington bolt the diameter is .694, and the boltway is .700-.701". If the knurling would raise the metal only .002 per side this would make the diameter .698, that to me would be a nice fit. I figure knurling a bolt would take 20-30 min.s, once setup.
Discussion?

 

[dmoran]

Dick -

I foresee no issues, and only foresee the benefits.
Would like to see what one done looks like. If it looks good, next I would consider fluting after the knurling.

Great idea......
Donovan

 

[wapiti25]

Go for it on your bolt.

 

[Bert]

Other than the out of round bolt condition mentioned earlier it would be easy to make a sample bolt. If you can knurl a bolt then you should have the equipment to turn a rod the same diameter as your bolt and knurl that. This would let you check fit and get an idea of pressure required to do it. I havent used anything diffrent than a standard knurling tool but i think they offer diffrent patterns i would see if you could find one that rolls a groove. You would want the groove to have a radius kind of like a bolt flute. You may have to make a custom roll for a knurling tool to do this? But all this seems lke a bunch of work when you could just sleeve the action.