thin rims with a File??

Got a 45/410 barrel here that will Not accept converted 303 brass due to fat rims. Nothing New there... but, want to use this brass in this gun!
Thinking of turning brass with drill, or lathe... got it in my head that a Bastard file without "teeth" on the edge, yea, they prolly gots a name... but...IDK. Anyway want to trim from case side...Not head, as I do Not want primers proud.
If anyone done this...LMK yer experience please...
yes, could just do it with lathe... but.. A File seems actually Easier.. with my current eyesight and hand eye coordination... I will probably end up with some Rimless with the lathe!!!:)

If you have accesss to a lathe then forget the file and set up cutting tool and face off what you need to. It will be much more accurate and consistent then the safe edged file.

Here is how I would set it up. I would pressure turn them on a mandrel and center. Turn a mandrel in the chuck to snugly fit the neck and long enough to reach the case head plus a little length. radius the end close to the cases. do not remove the mandrel until cases are all finished. Grind a HSS lathe tool with the lead edge close to straight/parallel ans the face edge around 45*, you want to be able to run right up into the relief groove or corner. Make a adapter for the live center, a flat face with a large center to fit on the live center.

Set up glue the adapter to the lathe center. insert case on the mandrel and back with medium to heavy pressure with tail stock live center adapter. lightly touch tool to rim face and set to cut to thickness, face rim into corner relief groove. Lightly deburr the sharp edge.

either set up an indicator to the carriage and use he carriage or turn the compound 90* and use it and the dial. At 45* the compound will read 1/2 of its graduations.

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Originally Posted by country gent

If you have accesss to a lathe then forget the file and set up cutting tool and face off what you need to. It will be much more accurate and consistent then the safe edged file.

Here is how I would set it up. I would pressure turn them on a mandrel and center. Turn a mandrel in the chuck to snugly fit the neck and long enough to reach the case head plus a little length. radius the end close to the cases. do not remove the mandrel until cases are all finished. Grind a HSS lathe tool with the lead edge close to straight/parallel ans the face edge around 45*, you want to be able to run right up into the relief groove or corner. Make a adapter for the live center, a flat face with a large center to fit on the live center.

Set up glue the adapter to the lathe center. insert case on the mandrel and back with medium to heavy pressure with tail stock live center adapter. lightly touch tool to rim face and set to cut to thickness, face rim into corner relief groove. Lightly deburr the sharp edge.

either set up an indicator to the carriage and use he carriage or turn the compound 90* and use it and the dial. At 45* the compound will read 1/2 of its graduations.

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Fixes at least one of my fears...needing to find center on each case... Had me Going!!!
Thanks

I make a lot of cases and use the lathe for many operations - including thinning rims. It is much easier than using a file. This is one of my videos, its about making .25 Stevens rimfire from .22 Hornet. At about the 9:40 point I start the rim thinning operation.
https://youtu.be/y_9G-FqDdKk

I made some 410 brass from Berdan 303 brass and modified the primer pocket to use 209 primers.
I used a live center in the primer pocket when I thinned the rim and reduced the outside diameter.
I was not satisfied with the results, the brass did not expand completely to the head of the case even after multiple annealing and fire forming.
The firearm used is a Ranger tube fed bolt action so I did not want to make the load too hot.

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Originally Posted by racepres

Got a 45/410 barrel here that will Not accept converted 303 brass due to fat rims. Nothing New there... but, want to use this brass in this gun!
Thinking of turning brass with drill, or lathe... got it in my head that a Bastard file without "teeth" on the edge, yea, they prolly gots a name... but...IDK.

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Look up safe edge files. That give you one edge of the file with no teeth so you can file up to a corner without damaging the other face.

Yep, the lathe is the way to go. Worked great when making cases for my 45-60 Winchester.

Was just thinking in this some more.
If you reverse the case in the set up it may be faster, and easier.
Turn the mandrel with a center in one end to use with the live center. again fit one end to the radius of the case head inside the case use a piece of 1" round stock 1" long face and bore square bottomed hole to match rim dia.
This has the advantage of since you are locating on the face of the rim, once thickness is set you should be able to lock the carriage and face them all to the same thickness.

I don't have a lathe but I do have many files , on the PPU brass it only takes about 12 pulls the case to get it to chamber ,I hold the file flat on my leg then pull the case from front to back one direction only ,with a good file takes very little effort . You might try some PPU 9.3x 74R brass it has a bit thinner rim than the 303 and makes a 3 inch shell instead of a short 2 1/2 , Graph & Sons has them in stock for 60.00 bucks for a 50 count bag
With all this being said I wish I did have a Lathe ,but for now poor boys have poor ways .

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Originally Posted by 15meter

Look up safe edge files. That give you one edge of the file with no teeth so you can file up to a corner without damaging the other face.

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Originally Posted by Fitz

I don't have a lathe but I do have many files , on the PPU brass it only takes about 12 pulls the case to get it to chamber ,I hold the file flat on my leg then pull the case from front to back one direction only ,with a good file takes very little effort . You might try some PPU 9.3x 74R brass it has a bit thinner rim than the 303 and makes a 3 inch shell instead of a short 2 1/2 , Graph & Sons has them in stock for 60.00 bucks for a 50 count bag
With all this being said I wish I did have a Lathe ,but for now poor boys have poor ways .

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Thanks to both of ya's.. I think I will at least give it a Go with said File... My Lathe is In a Very cold barn, and my friends is only slightly warmer...
Becoming more and More allergic to Cold, I will start in my Shop!!!
Later when Warmer, I will prove to myself If I should have simply waited out Lathe access...

I can understand want to take the material off the neck side not the breach face side but if for some reason it would be more convenient to take the material off the breach face side you could use large pistol primers so that the primers would not be proud. They are shorter. Should be fine for 410 pressures.

Just a thought.

Tim

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Originally Posted by dtknowles

I can understand want to take the material off the neck side not the breach face side but if for some reason it would be more convenient to take the material off the breach face side you could use large pistol primers so that the primers would not be proud. They are shorter. Should be fine for 410 pressures.

Just a thought.

Tim

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Very...very astute...Thank you for bringing that to my attention..

I don't have a lathe either and feel the need to apply innovative measures on occasion. A wrap of scotch tape or thin packing tape where you don't want material removed is very useful to protect the brass. I'd wrap the cartridges at the base and maybe use a strip of coke can to protect where I don't want to remove brass.

Clean your file frequently on the edge you want to cut and go slow.

If you can figure a way to effectively spin the case, you might be able to use a Dremel one-sided sanding disc. I'm guessing that you don't need to remove much metal. Take your time and it will work out fine.

[QUOTE=ndnchf;5524660]I make a lot of cases and use the lathe for umany operations - including thinning rims. It is much easier than using a file. This is one of my videos, its about making .25 Stevens rimfire from .22 Hornet. At about the 9:40 point I start the rim thinning operation.

Two questions - the parting tool you're using. HS steel or carbide?
Secondly since your drilling out the primer pocket for the acorn blank could you not thin the rim by facing it off?
Still getting used to all this lathe stuff.

Which brand of .303 brass are you using? European made brass will be within spec for .303 Brit. Whereas Rem and especially Win brass is always smaller/thinner.
https://uploads.tapatalk-cdn.com/202...d58965c261.jpg
Win vs PPU

Sent from my iPad using Tapatalk

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Originally Posted by ndnchf

Secondly since your drilling out the primer pocket for the acorn blank could you not thin the rim by facing it off?

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The OAL case length will be shorter by the amount removed from the rim if you cut from the headstamp side plus you lose the headstamp.

[QUOTE=Shanghai Jack;5525578]

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Originally Posted by ndnchf

Two questions - the parting tool you're using. HS steel or carbide?
Secondly since your drilling out the primer pocket for the acorn blank could you not thin the rim by facing it off?
Still getting used to all this lathe stuff.

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That is a carbide tool, but HSS would be fine too. I just happen to have that one set up in the quick change tool holder. I modify a lot of different cases and when the rim needs thinning, I always do it from the neck side. I make some .25 Stevens centerfire too.

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Originally Posted by muskeg13

I don't have a lathe either and feel the need to apply innovative measures on occasion. A wrap of scotch tape or thin packing tape where you don't want material removed is very useful to protect the brass. I'd wrap the cartridges at the base and maybe use a strip of coke can to protect where I don't want to remove brass.

Clean your file frequently on the edge you want to cut and go slow.

If you can figure a way to effectively spin the case, you might be able to use a Dremel one-sided sanding disc. I'm guessing that you don't need to remove much metal. Take your time and it will work out fine.

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Good Stuff...Thanks
will try

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Originally Posted by fred2892

Which brand of .303 brass are you using? European made brass will be within spec for .303 Brit. Whereas Rem and especially Win brass is always smaller/thinner.
https://uploads.tapatalk-cdn.com/202...d58965c261.jpg
Win vs PPU

Sent from my iPad using Tapatalk

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Most of mine is WW
, but, Note; the bit of European brass in the mix fireforms in one or two shots with no "waist"

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Originally Posted by M-Tecs

The OAL case length will be shorter by the amount removed from the rim if you cut from the headstamp side plus you lose the headstamp.

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Should Not be an Issue... the OAL is too short with 303 to start. a bit more sure ain't gonna matter... Headstamp??? maybe make our Own...401 Hickerbilly??

I’ve used a drill press and a HF mini mill to shape/thin brass over the years. Never thinned rims from the neck end but probably could build a jig and bearing to do it. Mini lathe would be the best though.

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Originally Posted by racepres

Got a 45/410 barrel here that will Not accept converted 303 brass due to fat rims. Nothing New there... but, want to use this brass in this gun!
Thinking of turning brass with drill, or lathe... got it in my head that a Bastard file without "teeth" on the edge, yea, they prolly gots a name... but...IDK. Anyway want to trim from case side...Not head, as I do Not want primers proud.
If anyone done this...LMK yer experience please...
yes, could just do it with lathe... but.. A File seems actually Easier.. with my current eyesight and hand eye coordination... I will probably end up with some Rimless with the lathe!!!:)

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Thinned the rims on 50 cases by chucking empty case in large Variable Speed drill , clamp drill in bench vice and then used Swiss Needle File to thin from back side , less material to remove and keep checking with calipers .
Not all of us have completed outfitted machine shops ... or any sort of lath .

Cajuns have to make do .
Gary

I converted some 50 .303 british to .410.

I just chucked each one in a cordless drill. Had a mill bastard file. Made a safe edge to go against the brass with 2 strips of duct tape.

Only took 20 to 30 seconds to reduce the diameter and the thickness to where they would chamber. I checked each one as I did it and once it chambered fully I chucked it back up and did a little polish with a piece of 0000 steel wool. They looked good and work well in my old Mossberg bolt action .410. I fireformed and loaded mild loads of Red Dot under a .40sw cast bullet.

Some of the bases don't blow all the way out, but they still work. and it isn't like I need the room for powder.

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Originally Posted by M-Tecs

The OAL case length will be shorter by the amount removed from the rim if you cut from the headstamp side plus you lose the headstamp.

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Losing the headstamp seems to be a plus since it will be wrong.

Tim

I shortened the diameter of 45-90 casesesto fit 43 Mauser I bought the biggest drill that would fit the cases mouth chucked it in a drill and used a little hose clamp to hold it. Didn’t tighten it all the way down. Quick fast 20 cases, actually 2 1/2 hours. Then use file with protection. Hand held.

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Originally Posted by Gobeyond

I shortened the diameter of 45-90 casesesto fit 43 Mauser I bought the biggest drill that would fit the cases mouth chucked it in a drill and used a little hose clamp to hold it. Didn’t tighten it all the way down. Quick fast 20 cases, actually 2 1/2 hours. Then use file with protection. Hand held.

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if you want to chuck a case by the mouth, put a plug in the mouth and then you can clamp it pretty hard without collapsing it. We had to do that when tensile testing tube welds, we put a plug in each end of the tube and then clamped it in the tensile test machine. I am thinking you could just use a bullet for the plug and then when you are done you could just pull the bullet.

Tim

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Originally Posted by GhostHawk

I converted some 50 .303 british to .410.

I just chucked each one in a cordless drill. Had a mill bastard file. Made a safe edge to go against the brass with 2 strips of duct tape.

Only took 20 to 30 seconds to reduce the diameter and the thickness to where they would chamber. I checked each one as I did it and once it chambered fully I chucked it back up and did a little polish with a piece of 0000 steel wool. They looked good and work well in my old Mossberg bolt action .410. I fireformed and loaded mild loads of Red Dot under a .40sw cast bullet.

Some of the bases don't blow all the way out, but they still work. and it isn't like I need the room for powder.

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What I did ... but in a drill press.. I also neede to take some off at the Head where it joins the Rim... Just a Bit, as they were Too Large there..

If you need to reduce the rim Diameter, a drill press and a file will do the job without much fuss as the diameter is not too critical. However if you need to reduce the rim thickness thats a different story. The thickness should be removed from the body side of the rim. That way you do not effect the primer pocket depth. Here is a pic of my set up in the lathe to reduce rim thickness. Its accurate and repeatable and its very easy to hold .001" +/- on the thickness. If the body needs thinned a little at the web that can be done the same way as well.
Attachment 310865
Friction drives the case, it sets in a pocket just large enough to fit the case head. Plug in the case mouth should fit snugly. Best to do with sized cases to the inside diameter of the mouth of the case is consistent so you don't have any problems getting the plug in and out.
Sam

^^^^ Nice

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Originally Posted by racepres

Got a 45/410 barrel here that will Not accept converted 303 brass due to fat rims. Nothing New there... but, want to use this brass in this gun!
Thinking of turning brass with drill, or lathe... got it in my head that a Bastard file without "teeth" on the edge, yea, they prolly gots a name... but...IDK. Anyway want to trim from case side...Not head, as I do Not want primers proud.
If anyone done this...LMK yer experience please...
yes, could just do it with lathe... but.. A File seems actually Easier.. with my current eyesight and hand eye coordination... I will probably end up with some Rimless with the lathe!!!:)

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I drilled a short piece of 2x4 with holes to hold the 303 brass, then ran the exposed rim surfaces across the circular sanding disc on my belt sander, until the rims were thin enough to chamber.

Firearm Nut

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Originally Posted by Firearm Nut

I drilled a short piece of 2x4 with holes to hold the 303 brass, then ran the exposed rim surfaces across the circular sanding disc on my belt sander, until the rims were thin enough to chamber.

Firearm Nut

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Great concept... but, the area just forward of the rim is too large in diameter for My Particular 410 also.. using a Non-safety edge File gets em where I need em...

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Originally Posted by Firearm Nut

I drilled a short piece of 2x4 with holes to hold the 303 brass, then ran the exposed rim surfaces across the circular sanding disc on my belt sander, until the rims were thin enough to chamber.

Firearm Nut

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Did you have to re-cut the primer pockets? Taking off the back side would make the primer pockets too shallow, or so I would think.

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Originally Posted by 15meter

Did you have to re-cut the primer pockets? Taking off the back side would make the primer pockets too shallow, or so I would think.

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Use pistol primers...which IMO is best anyway

I had a issue with one lot of Winchester brass in 45-70 that did not allow the breech to close on my Sharps. My Sharps has a tight chamber and a minimum rim recess. The brass was within specs for rim thickness but several thousands thicker than my R-P. Not having a lathe I used a piece of heavy glass and 320 grit sand paper. Held the case heads flat on the sand paper and removed enough for the breech to close. Only took a few thousands then used a uniforming tool on the primer pockets. Kind of slow and tedious but worked.

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Originally Posted by Sgt H

I had a issue with one lot of Winchester brass in 45-70 that did not allow the breech to close on my Sharps. My Sharps has a tight chamber and a minimum rim recess. The brass was within specs for rim thickness but several thousands thicker than my R-P. Not having a lathe I used a piece of heavy glass and 320 grit sand paper. Held the case heads flat on the sand paper and removed enough for the breech to close. Only took a few thousands then used a uniforming tool on the primer pockets. Kind of slow and tedious but worked.

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Long as it was effective..good on ya