Knurling the boolit ?

[Digger]

When I picked up a deal on a Metallic 2 back when .....
also in the odds and ends was this "knurling " setup .. maybe a CH ?
Any how , what is the purpose or was the purpose of the Knurling process ? , if any one would know.
appreciate it much.

210279210280210281

[Hannibal]

The only benefit I am aware of to 'knurling' cast bullets is to facilitate the application of grit for fire lapping.

If someone has other information, I'd be curious to hear it.

[Nueces]

That is the CH cannelure tool, for rolling a crimping cannelure into a swaged jacketed bullet. The knurled edge acts as a driver to rotate the bullet during the operation.

[Hannibal]

That is the CH cannelure tool, for rolling a crimping cannelure into a swaged jacketed bullet. The knurled edge acts as a driver to rotated the bullet during the operation.

Ah! That makes perfect sense.

[rancher1913]

it also helps with holding lube, lots of tumble lube boolits use this

[Traffer]

The only lead knurled bullets I know of are for 22 rim fire bullets. You may notice that they are all knurled. It is because the bearing surface is the same diameter as the case and therefore the bearing surface is on the outside of the case. So there is no where to put lube except on the outside of the bullet. Bullet manufacturers use the knurled surface to hold the lube. There is no need for this when powder coating. Which is why I believe that 22 rim fire bullets will be powder coated in the future. I have been loading non knurled 22 rim fire for the past couple of years. I have also knurled 22 rim fire bullets to hold the lube in the past. Here are some representative pictures.
210284210285210286 This last picture is of a knurled semi-wad cutter that I made early on in my development of 22LR reloads. It has a nice deep knurl for lube.

[Hannibal]

The OP does not specify the caliber, but given the description, I do not think they are 22 RF bullets. (?)
It appears that the mechanism is adjustable for caliber. (?)

Not to hold anything back from Traffer. That is 'Way cool!'

I wish I could do that.

[runfiverun]

the op's pic is a gannelure tool it is used for all calibers.
it come with the edge shown, one with 2 cannelures, a 3 place knurling tool, and a couple of other inserts could be made or used.
I have the exact one shown [with the 3 inserts above] and they are meant to be mounted sideways not flat on the bench.
I use it to add knurling for holding lube to my slick sided 358 swaged bullets and to add a cannelure my 44,22, 45, & 308 jacketed bullets.
I also add cannelures to stuff like 230gr XTP's meant for the 45 acp so I can use them in my 45 colt lever guns.

handy little tools to have around.

[David2011]

Seems like some of the .38 caliber swaged wadcutters I used years ago were knurled but as stated, the tool shown is a cannelure tool; not a knurler.

[Hannibal]

Seems like some of the .38 caliber swaged wadcutters I used years ago were knurled but as stated, the tool shown is a cannelure tool; not a knurler.

Just noticed your Sig line.

A one way street?

I hope not. I've made far too many mistakes.

[Mr_Sheesh]

I think the "one way street" thing means that we're on the street from birth to death, just have to figure out how long a street that IS for you? Song lyrics @ http://www.songlyrics.com/jim-morris/livin-till-the-day-i-die-lyrics/

[Digger]

And so the education continues ...
thank you so much gentlemen !, highly appreciate all the info .
The boolit in the pics is my Hensley & Gibbs #20, 170 gr. that I scrounged a while back .
So far it is an excellent performer in my 30 cal toys ..
Once again , really appreciate the older items.

[JBinMN]

May not be particularly applicable to this topic, but you can "knurl" things by placing the item to be knurled in a vice with two files on each side in the jaws, tighten the vice just a bit depending on the material to be knurled & tap the end of the files towards the vice. The rotation of the item in the file "teeth" & proper pressure on it dependent on type of material, will sometimes knurl the item in between.

I recall some folks doing that to piston skirts to help keep oil up on the cylinder walls & piston skirts for lubrication. I reckon it would do the same for boolits, although I wonder if one did it for boolits that way & it might cause gas cutting if too far down on the base. Some folks will try this on some types of tool shafts to aid in gripping them when they are greasy/slippery. ( Think "drifts", screwdriver shafts & socket extensions for example).

Anyway, it was just a thought to share & if not applicable, then just forget about it. Consider it some possibly "useless" knowledge you now have in the back of your head, if ya did not know about it before. LOL
;)

[upnorthwis]

I was thinking that a knurled J-word bullet would be great for removing stubborn leading. Now I might try it with the vise method.

[jdfoxinc]

Dave at CH made a knurling attachment for a dedicated lead bullet customer. I bought one of the over run parts with the cannelur tool. It did a good job unless you pressed down too hard. Then the two rollers the bullet rides on would iron out telhe knurl.

[Victor N TN]

It looks identical to my C-H canneluring tool. I use it to put a crimp groove in jacketed bullets for my 300 WinMag. If they don't have it, the bullets will work back into the case with the hard recoil.

[vzerone]

May not be particularly applicable to this topic, but you can "knurl" things by placing the item to be knurled in a vice with two files on each side in the jaws, tighten the vice just a bit depending on the material to be knurled & tap the end of the files towards the vice. The rotation of the item in the file "teeth" & proper pressure on it dependent on type of material, will sometimes knurl the item in between.

I recall some folks doing that to piston skirts to help keep oil up on the cylinder walls & piston skirts for lubrication. I reckon it would do the same for boolits, although I wonder if one did it for boolits that way & it might cause gas cutting if too far down on the base. Some folks will try this on some types of tool shafts to aid in gripping them when they are greasy/slippery. ( Think "drifts", screwdriver shafts & socket extensions for example).

Anyway, it was just a thought to share & if not applicable, then just forget about it. Consider it some possibly "useless" knowledge you now have in the back of your head, if ya did not know about it before. LOL
;)

You can just lay one file on a table and put a bullet or two on it and place another file on top and roll them. If you place the files in opposite direction from one another you get a different pattern.

Knurling pistons was a cheat when the piston was worn undersize to the cylinder to get a tighter clearance. It doesn't last long.

[JBinMN]

You can just lay one file on a table and put a bullet or two on it and place another file on top and roll them. If you place the files in opposite direction from one another you get a different pattern.

Knurling pistons was a cheat when the piston was worn undersize to the cylinder to get a tighter clearance. It doesn't last long.

I suppose with lead it would not take much pressure. So, doing it on a table top would likely be just fine.

Other, harder stuff, I think using the vise would be better.

As far as the piston thing... Perhaps you and I are not talking about the same type of piston & cylinder relationship.

The "rings" on the reciprocating engine pistons I was referring to, were what hold the piston in the cylinder to keep the piston ( & skirt) from riding the walls of the cylinder, while the skirt of the piston would get "splashed" by the crankcase oil & carry the oil(lube) up to the walls of the piston, while the lower "oil" ring(s) "washed" the oil back down the sides & the upper " compression" ings held the piston in place & sealed the combustion chamber off from the crankcase. When the piston "skirt" was to rub on the sides of the cylinder , we called it "Galling" of the piston or the cylinder ( or both) & that was usually due to some "slop" in the rings, the piston "wrist pin" & bushings , upper connecting rod bushings or some of all. None of which is desired. With the piston being "knurled" as was mentioned, it would help that oil "wash" from being wiped down as fast by the knurling. And yes, it was used as a "fix" & was not always a good one. Once the piston/cylinder get to "galling" it would be best to replace the parts mentioned since it means trouble if one does not. I imagine it would help though, even after a rebuild or reassembly to get & keep that crankcase oil washing the two areas.
:)

"Nuff said by me, anyway... Ya'll please continue. I love learning new things & not always run my mouth. (or use hands to type).
:)

[2wheelDuke]

Seems like some of the .38 caliber swaged wadcutters I used years ago were knurled but as stated, the tool shown is a cannelure tool; not a knurler.

I've loaded many wax coated, knurled .38 wadcutters when I was starting out. They always leaded my bores. They were super soft. The ones we cast and lubed with 50-50 never gave that problem. I added any of the ones I had left to my pot.

And that's definitely a cannelure tool for jacketed bullets. I believe you could also add a cannelure to a case if you wanted to.

[mdi]

Knurling will increase the diameter of a bullet. I have knurled rods/axles when I needed a few thousandths to insure a snug fit. The cannalure tool will "cut" or "push" a groove in a round surface/rod/bullet just like a pipe cutter does (I actually made a "grooving" tool by dulling, rounding off the cutting wheel in a tubing cutter...).

[Traffer]

May not be particularly applicable to this topic, but you can "knurl" things by placing the item to be knurled in a vice with two files on each side in the jaws, tighten the vice just a bit depending on the material to be knurled & tap the end of the files towards the vice. The rotation of the item in the file "teeth" & proper pressure on it dependent on type of material, will sometimes knurl the item in between.

I recall some folks doing that to piston skirts to help keep oil up on the cylinder walls & piston skirts for lubrication. I reckon it would do the same for boolits, although I wonder if one did it for boolits that way & it might cause gas cutting if too far down on the base. Some folks will try this on some types of tool shafts to aid in gripping them when they are greasy/slippery. ( Think "drifts", screwdriver shafts & socket extensions for example).

Anyway, it was just a thought to share & if not applicable, then just forget about it. Consider it some possibly "useless" knowledge you now have in the back of your head, if ya did not know about it before. LOL
;)
Your friends were some dam fine mechanics. Not many know that trick. The way I knurled the bullet in the picture was to lay the boolit on a file that was on a bench then take another identical file and roll the boolit between them. With a little practice it works very well. For those who want to hold grease on a 38 or any other long bearing surface slug (like a wad cutter) without grease grooves, this method may be just the ticket for you.
Fyi There is not much difference between knurling and canneluring a boolit. Knurling is more a term for making the checker pattern on a lathe though. Most people think of canneluring when making a pattern of cuts around a boolit or more likely a jacketed bullet. Cannelure machines are also used for making cannelure patterns on cases. They pretty much work the same though. By pressure they cut or mash dents into the bullet or case by rolling it between some type of forming tool.
Here is a link to a video I made about rolling a bullet between two files. I did a very poor job in the video but you get the idea here: https://www.dropbox.com/s/o8j2s3z0lumgm9y/KnurltoCrimp.MP4?dl=0

[Ballistics in Scotland]

You can just lay one file on a table and put a bullet or two on it and place another file on top and roll them. If you place the files in opposite direction from one another you get a different pattern.


The tricky bit is knurling all of them to the same depth. A pair of metal rollers to determine the difference between the files would probably work

With rotary knurling devices, including proper lathe knurls, the depth of knurling determines the diameter, and thus the circumference. It starts out an irregular rough surface, and then settles down to regular knurling when the diameter becomes an exact multiple of the knurling pitch So the depth is self-indicating.

I think knurling would work with moderate pistol velocities, but wouldn't hold enough lube for a rifle bullet to reach the muzzle before running short. If you use a hard lube, the use of a toothed wheel in the bottom of lube grooves might reduce the tencency for it to break out.

[labradigger1]

Your friends were some dam fine mechanics. Not many know that trick. The way I knurled the bullet in the picture was to lay the boolit on a file that was on a bench then take another identical file and roll the boolit between them. With a little practice it works very well. For those who want to hold grease on a 38 or any other long bearing surface slug (like a wad cutter) without grease grooves, this method may be just the ticket for you.
Fyi There is not much difference between knurling and canneluring a boolit. Knurling is more a term for making the checker pattern on a lathe though. Most people think of canneluring when making a pattern of cuts around a boolit or more likely a jacketed bullet. Cannelure machines are also used for making cannelure patterns on cases. They pretty much work the same though. By pressure they cut or mash dents into the bullet or case by rolling it between some type of forming tool.
Here is a link to a video I made about rolling a bullet between two files. I did a very poor job in the video but you get the idea here: https://www.dropbox.com/s/o8j2s3z0lumgm9y/KnurltoCrimp.MP4?dl=0

Knurling will increase diameter. Knurling displaces metal and it can’t flow in so it flows out.

[Traffer]

Yes knurling does increase the diameter. However, the knurled surface is also softer than without the knurl because it compresses down back onto itself. So the gain in diameter is not a big deal.

[Jack Stanley]

Knurling will increase diameter. Knurling displaces metal and it can’t flow in so it flows out.

Sounds like a good idea for low velocity and tumble lube if you don't want to leement the mold .

Jack

[reloader28]

Theres knurled bullets in my Speer or Hornady books. I always figured that was for lube

[country gent]

Swaged lead bullets have no lube grooves, lube grooves need to be rolled in or knurled afterwards to hold lubes. A lot of the swaged pistol bullets are knurled and dry lubed with mica. Another place it might help is with PC or high tech coatings. Knurling will increase the size. but the surface area is much less due to the diamonds so its softer and squeezes down easier.
The military converted some bigger pipe cutters to knurling tools for armorers to use to "fit" the op rod guides to M14s during rebuilds. The rolling between 2 files works for bullets also.

[Ateam]

I have used the file method to both increase the diameter of and achieve a better fit to sabots in smokeless muzzle loaders. Sometimes without the knurling, the projectile will "drill" the sabot, knurling gives it something to grab a hold of and usually fixes the situation.

[Ateam]

A word of caution.
I have seen aggressively file knurled J-words breaking off file teeth in the jacket (usually cheap Chinese files). This would result in a doozy of a bore scar if fired.

[Motor]

Knurling will increase the diameter of a bullet. I have knurled rods/axles when I needed a few thousandths to insure a snug fit. The cannalure tool will "cut" or "push" a groove in a round surface/rod/bullet just like a pipe cutter does (I actually made a "grooving" tool by dulling, rounding off the cutting wheel in a tubing cutter...).

Add to this list pistons for car and truck and other engines as well as valve guide bores and other bores. Of course doing small bores requires different style tooling.

For swedged or cast boolits it will increase the diameter and provide an excellent surface to hold lube and will be easy to size.

Motor

[longbow]

Corbin makes knurling tools to allow lubing of smooth swayed boolits.

I did the same thing for boolits from my push out moulds... look up Ideal Cylindrical molds. They were intended for PP boolits but if the mould is made about 0.093" undersize then knurled, it can be lived a
Then sized... or if you get it right just knurled, lived then loaded.

As already pointed out the pic in th OP is a cannelure tool but you can likely by knurling rollers too.

Longbow

[rmatchell]

The ch tool you have will work fine if you want to cannelure or even knurl if you wanted to reset it a few times, but your hands get sore after awhile with the small handle. Chuckbusters tool is hard to top for long term use.

On a side note if you want to tumble lube try mixing half a bottle of lee lube with a 1/4 pound of parfin in a pint jar filled with naptha. Drys hard and clean to load and shoot.

[DukeInFlorida]

Chuckbuster's Ultimate Cannelure Tool is absolutely the very BEST way to put a knurl on the outside of the cast boolits. He offers a diamond knurl wheel, in addition to the standard knurl/cannelure wheel. It would place a nice (approx 3/8") wide knurl on the boolit, which would give additional surface area for any coatings, such as the Lee Alox lube.

Chuckbuster is a Vendor Sponsor, and has his offerings here:
http://castboolits.gunloads.com/forumdisplay.php?206-Chuckbuster

[Digger]

Fascinating ....
so much info here with all this input .
Just another facet of our hobby/sideline for all to learn if not brought to light for others benefits ongoing here.
thank you much gentlemen !

[Traffer]

The tricky bit is knurling all of them to the same depth. A pair of metal rollers to determine the difference between the files would probably work

With rotary knurling devices, including proper lathe knurls, the depth of knurling determines the diameter, and thus the circumference. It starts out an irregular rough surface, and then settles down to regular knurling when the diameter becomes an exact multiple of the knurling pitch So the depth is self-indicating.

I think knurling would work with moderate pistol velocities, but wouldn't hold enough lube for a rifle bullet to reach the muzzle before running short. If you use a hard lube, the use of a toothed wheel in the bottom of lube grooves might reduce the tencency for it to break out.

Yup lot of room for experimentation in that. I thought of just using pieces of near .22" roller bearings to place between the files to act as stops so the crimp would be uniform between boolits. But I discontinued the experimentation when I started to powder coat. Powder coat works fine on the long bearing surface without any grooves or knurling.