Making a Barrel Channel Scraper from a File

[ejcrist]

I just finished making an octagon barrel channel scraper from a mill bastard file per Jim Turpin's video on assembling a Jim Chambers flintlock. It came out good and works really well but I'd like to put about a 45 degree bend in it at about the halfway point of the length of the file. I'm thinking to heat the center with a propane torch until cherry red and the bend it with a hammer and anvil. I know absolutely nothing about metallurgy and was wondering if this will make the file significantly more brittle than it already is and cause any problems. If anyone with experience in these matters could let me know I'd very much appreciate it.

Thanks, Gene

[waarp8nt]

I made a internal powder horn scraper from an old screw driver. Heated hammered the tip to the shape I wanted and bent it as needed. I quenched mine in oil. If memory serves me correctly...you heat it and air cool or put it in sand to soften the metal. When all done you will need to quench in oil or some other fluid to retain hardness.

[seaboltm]

Heating the file will make it soft.

[ejcrist]

Ok, got it. I'll heat her up and oil quench after bent to shape. I'm guessing it ain't too critical in my case since I'm heating and bending the center section only. Thanks for the info.

[country gent]

Also keep in mind if the teeth are still on the file beding is likley to crack in the teeth. We made scrapers from files and forged them to a tapered form and removing the teeth in the process. hand files or coarse stone polished and then the end was shaped and sharpened. Heating and slow cooling softens the file some. heating and quenching hardens to full hardness ( usually to hard to be useable) the a controlled heat and cool to draw back to useable may be required

[ejcrist]

Also keep in mind if the teeth are still on the file beding is likley to crack in the teeth. We made scrapers from files and forged them to a tapered form and removing the teeth in the process. hand files or coarse stone polished and then the end was shaped and sharpened. Heating and slow cooling softens the file some. heating and quenching hardens to full hardness ( usually to hard to be useable) the a controlled heat and cool to draw back to useable may be required

When you say too hard to be useable, do you mean too hard to function as a scraper? I grinded the one side smooth so no teeth, and beveled the edges at about a 45 degree angle. The shape is slightly smaller than the smallest section of the swamped barrel.

[country gent]

A file heated and quenched with no draw back can be brittle allowing the edge to chip easily or worse break and stab into your hand arm. Im assuming you are drawing this so the stabbing may not happen. Drawing back to med straw color and slow cooling will normalize and remove alot of the brittleness. The scrappers we made were for scrapping machine parts during re fitting rebuilds. They cut cast iron and bronve were pished hard and when cutting gull wings recieved a hard shock.

[ejcrist]

Ok, I think I'm following you. I'll give it a go.

[seaboltm]

After quenching put it in your oven to about 400 degrees for an hour or so. That should leave it hard enough to do the job, not too brittle.

[OuchHot!]

If I understand, you have the cutting head the way you want it. If that is clamped in a vise (aluminum jaws might help) it will not draw when you heat the part that you want to bend. Air cool the part that you have bent as there is no reason for it to be hard. I may not have understood what you're doing so ymmv!

[Omnivore]

Heat treating of tool steels (hardening and tempering) is a very, very old parctice and so all you have to do is seaqrch the internet for exact instructions and video demonstrations.

The responses here are accurate, but they use jargon terms you may not understand, such as "drawing" and so on. That is just another word for tempering, or "drawing a temper" is another term I've heard.

As far as using color to determine temper; you can't do that unless you've polished the metal back to white after it was hardened, i.e. you must take off the oxide scale after hardening, or color either doesn't show at all or it's meangingless.

As was said above; if the section you want to bend is not immidiately adjacent to the part you want to use for cutting, then you don't need to quench or worry about hardness or temper at all - just make sure it's not going to be super brittle, which means you let it air cool.

In short; if you want to reform the metal for use as a cutting edge (making a graver out of a small file for example), you do all your heating and bending and grinding and whatnot, after which the heat treating is all *****, and THEN you harden it, and temper it if necessary. Different steels will require different heat treating processes, i.e. some should be quenched in water and others in oil (oil cools the steel a bit slower than water) and some are air-hardening. I've quenched re-shaped files in water and had no problem with cracking, and then tempered them only very slightly, to light straw color, and have been able to engrave barrel steels with it afterward. Your need to cut wood is a low bar to clear, so you have lots of room for error.

For hardening, by the way, the steel must typically be heated to its "transition point" meaning that a magnet will no longer stick to it. That's your temperature gauge - you keep a magnet with you as you're heating your part. As soon as it doesn't stick, quench the part. Some steels of course won't take to hardening much at all, unless you add a case-hardening compound. A file of course will harden up nicely.

[johnson1942]

when i built my last rifle i had a router bit that was for that barrel channel and i took the stock out to a friend of mine who has a milling machine and with that router he cut a barrel channel that was perfect for that channel. i admire those who can do it by hand but i prefer a router and a milling machine as it can't get more perfect then that . you may have to glass bed it when you are done by hand but if you dont you are a master craftsman . me i like machines and my guns speak for them selves. tools where made to help man, its not cheating it just gives you the edge. the gun im building soon will have a machined barrel channel and it will win match after match. i like traditional but modern machines like a milling machine can make it happen easier.

[ejcrist]

when i built my last rifle i had a router bit that was for that barrel channel and i took the stock out to a friend of mine who has a milling machine and with that router he cut a barrel channel that was perfect for that channel. i admire those who can do it by hand but i prefer a router and a milling machine as it can't get more perfect then that . you may have to glass bed it when you are done by hand but if you dont you are a master craftsman . me i like machines and my guns speak for them selves. tools where made to help man, its not cheating it just gives you the edge. the gun im building soon will have a machined barrel channel and it will win match after match. i like traditional but modern machines like a milling machine can make it happen easier.

Omnivore - Thanks much for the detailed info. I needed it dumbed down below metallurgy for dummy's and you hit the mark perfectly. Believe it or not I had three years of welding vo-tech in high school but it's been so long I don't even remember what I forgot, and I haven't done any metalwork since then, so thanks again. I got this now.

Johnson1942 - This is a swamped barrel so power tools aren't in the equation for me. If I were doing a straight barrel I'd be more inclined to use a router for the initial channel cut but I'd definitely make it undersized or I'd cut too much if I sneezed the wrong way. Either way I'd want to finish the channel with a scraper. I'm not in any hurry so it doesn't matter if it takes me a while. But it's a good thought and I agree with you on the power tool usage.

Gene

[johnson1942]

i under stand, if their are voids from free carveing this is what you do. take layers of brown stained paper towel and soak it with gorilla glue and press into the voids. then wrap your barrel with plastic thin wrap a couple of wraps. then press it into the channel and let the paper between the wood and the barrel dry completely. this will give you a perfect barrel channel when it dries, the same as if you glass bedded it. it dries hard and perfect and stays their forever. the plastic wrap allows your barrel to come out of the barrel channel when the whole thing dries and their you are next to perfect. you dont have to make a perfect carveing on the channel but this method will make the channel perfect and the stained browned paper will just need to be sanded at the edges where it meets the stock at the top. as good as glass bedding and much easier.

[LAGS]

All of my barrel channel scrapers are made out of old files.
I always needed a certain shape and at the time a Jim Fisher scraper was out of stock, or I didn't have time to wait to have one shipped to me.
A MAPP gas torch is all you need to do the annealing and rehardening.

[bedbugbilly]

Many years ago, when I was still making rifles, I took one of the old Sears single knife molding heads (that was used on table saw and radial arm saw) and purchased a number of the 1" square "dado" cutters. We had a lumberyard and I could buy them in sets of three (Vermont American made them for their 3 knife molding heads).

I ground a set of knives for various barrel sizes - 1", 15/16", 7/8" and 13/16". The single knife molding head worked very well as far as being "balanced". I would install a molding head "throat plate" on my table saw and clamp another heavy wood guide on the table so the stock blank was snuggly guided between the fence and the guide block.

The stock blank (either full stock or half stock) was run through the planer sot that it was equal thickness the full length. I would then mark the stock blank and the guide so I knew how far to feed the blank on the saw so that the barrel channel stopped in the correct spot. With repeated feeds into the saw and raising the cutting depth, a very nice smooth octagon barrel channel could be cut in short order. The breech area was then cut square by hand with the appropriate sharp hand chisels. I used this molding head cutter on a variety of species - straight grain cherry, curly cherry, hard maple, curly maple, walnut and even white ash.

On full stocks, I then made tight guides on my drill press - I installed a 3/4" "table" on the drill press table (bolted in place). Using the appropriate round nose router bit or two flute milling cutter, I could run the stock through the guides and by slowly adjusting the spindle of the drill press down and locking it in place, I could cut the ramrod channel until it was the correct depth. This operation has to be done before the foreshock is cut so that the edge of the foreshock is the correct height for the side flat of the barrel (top of stock blank is first run over a jointer to square it up with the sides of the planed blank - when the barrel channel is then cut on the table saw using the molding head, the depth of the barrel channel is the same or just a tad more than the size of the barrel across the flats).

For drilling the ram rod hole on a full stock - I usually used two sizes of ram rod hole drill bits - 5/16" or 3/8" depending on the caliber of the barrel and the desired ram rod size. Once the ram rod channel was routed in the stock blank - I made hardwood "guides" (usually hard maple) that were also grooved out that could be clamped to the forearm of the blank - thus providing round hole to help keep the ram rod drill in place in the channel when the guide blocks were clamped to the foreshock. My ram rod drills were made from round stock with a "brad point" wood twist bit brazed on the end. I never used an electric drill to drill the ram rod hole. I always used a "hand brace". I clamped the stock blank to my workbench and would drill the hole by hand. You have to remove the bit often to clear the chips and I would blow in some chalk line chalk into the hole for lubrication. Depth of the hole can be determined by laying the bit on the blank so that the end of the bit is in line with the end of the barrel channel not he breech end - then just wrap one wrap of masking tape around the drill bit rod so that you stop drilling when the tape reaches the entry hole where your entry thimble will be installed.

I never had a problem with the drill bit wandering - maybe I was just lucky but the secret is to take your time and do it by hand. For cutting the barrel channel, setting up the fence and guide block was the most time consuming - with repeated cuts raising the cutter depth on each pass, a complete barrel channel could be done in a half an hour or less - ready for hand finishing the breech end of the channel. The ram rod channel could be routed in about the same time. The drilling of the ram rod hole was also fairly fast - usually less than an hour and most of that was checking and worrying about any "run out".

Once the barrel and breech plug and tang were inlet and pinned (I usually used pins to secure the barrels), the ram rod thimbles inlet and the pin holes drilled - I moved on to inletting the lock. As everyone knows, the correct placement is the most important part whether it be percussion or flint in terms of either drum placement or vent placement. Once that was determined and the outline of the lock plate drawn on the stock, I proceeded to inlet the lock and make the lock mortise. I used to do it all by hand but I found that much of the work could be taken out of it by using a variety of "forester bits" which make a flat hole. Using the correct size bits, I could set the depth on my drill press and "rough out" most of the profile of the lock plate - the forester bits made the bottoms of the hole the correct depth and the final inletting could be done by hand. Once the lock plate was inlet, it was just a matter of locating the internal screw locations and drill them to the correct depth, then inletting the tumbler, bridle, drilling the sear hole to the correct depth (using a small forester bit), the sear spring and the main spring. Once the complete lock was inlet - the lock bolt holes could be drilled. From there on - locating and fitting the trigger, trigger guard, side plate or washers and then the butt plate.

A lot of folks don't think they could make a rifle from scratch - but if they have some basic woodworking and metalworking ability along with a few tools . . . and they think out what has to be done and in what steps and order they need to be done - a nice rifle can be assembled that will be a great joy to shoot and give them the satisfaction of creating it themselves. Sometimes it is necessary to make some speciality tools - like the scraper the OP made - but it can be accomplished.

As far as shaping a stock blank - I very rarely used "rasps" of any sort. I used a combination of various wood carving gouges - especially for profiling the wrist and butt stock. With careful se of the right gouges, you can carve and shape a cheek piece that will require only final sanding. I also used an old fashioned antique wood "draw shave" for shaping the forearm and butt. If you want to put "molding" along your ram rod groove - simple small scrapers can be made out of various things such as "cut masonry nails" ground to shape and attached to a round "guide" that will run in the ram rod groove as you scrape the molding profile.

Sorry for the "dissertation" but I just wanted to give some more ideas of what can/could be used - there are many ways to "skin a cat" and you are only limited by your imagination!

[ejcrist]

Thanks again for all the info fella's. Just as a follow-up, I purchased a mapp gas kit from Homeless Depot (http://www.homedepot.com/p/Bernzomatic-TS4000KC-Trigger-Start-Torch-Kit-336634/203368730) and used it to heat the file up enough and it only took about a minute or so before I could easily make the bend. The propane torch I had just wasn't cutting it (or rather bending it). Anyway, all is well in my universe again. Thanks for your help.