Author Topic: Cut off tools (Read 1298 times)

handirifle · « **on:** January 02, 2008, 05:20:21 PM »

I'm going to order some videos to learn this stuff (no time to attend a class), but in the mean time I want to pick you guys' brains.

Is this a good cut off tool for cutting my copper bullets? Would it also cut steel?

Would this be a good cutter to shorten a barrel?

How would you guys go about putting a target crown on a new cut barrel? What cutting tool would you reccomend?

Brithunter · « **Reply #1 on:** January 03, 2008, 12:03:19 AM »

Have got the proper holder for that blade?

Use of steel will depend upon what the blade is made of. HSS (High Speed Steel) will cut steel but you still need cutting solution/oil. Also are you aware they come in different thicknesses? For copper bullets a narrow one would be best in my opinion. The top rake is different for both materials for best cutting.

Oh some of those blades are a sintered metal and shatter if dropped on concrete floors or twisted in use and another thing to consider is that parting off places more strain on the headstock bearings that a lot of operation except maybe forming. Capstan lathes and lathes fitted with collect or ball chucks are best for thei use as the support is closer to the workpiece.

The other thing to note if you leave the front cutting edge of the blade square it will leave a large pip on the workpiece, but if you grind an angle on it it wll leave the parrted off piece with a clean face and by facing across the bar left it should (if you have it set right) also leave no pip. Getting the tool on centre height it vital with parting blades. As too using it to part off a length of barrel, yes it will do the job however you want to get the point of cut as close to the chuck/collet as possible to provide support and stiffness or the barrel if left far out will attempt to climb over the tool.

As to facing and crowning barrels ............................... well target crowns caome in several types. The 11 degree crown is also called a targer crown as is the recessed one. Either can be done with the same tool. I would use a stubby single point boring tool, just make sure it has enough clearence so it does not rub below the cutting edge, both front and side clearence that is.

John Traveler · « **Reply #2 on:** January 03, 2008, 12:45:11 PM »

I agree with brithunter. You need a proper holder for that cutoff blade, and also the grinding wheel and stones to sharpen it properly. Study the tool sharpening tips given on the home shop machining sites to understand what is needed.

Cutting copper and copper alloys is a bit tricky. Generally you need a thin blade and VERY sharp cutting tool, because the material tends to stick to the tool. This is even more important when you are shortening existing jacketed bullets with lead cores.

That tool will do for cutting off a barrel, but you need another bit to do the barrel counterbore. You can buy the pre-ground crowing tool, or just do like I do and grind it yourself.

May I suggest browsing the Internet home gunsmithing sites for detailed explanations on lathe gunsmithing work. Plus, you really should get a copy of the South Bend or Atlas "How to Run a Lathe" handbooks. There is also an online e-book of the US Army technical manuals on how to run basic machine shop machines, tool sharpening, cutting techniques, etc that will be really usefull to you.

You are in Lancaster, California? I'm not too far away, in the Los Angeles area. Feel free to send me email if you ed any help.

John

The Gamemaster · « **Reply #3 on:** January 03, 2008, 01:27:31 PM »

Things that makes you go Hummmmm.

Maybe I ought to post the picture of a rifle shell and ask you if it would be a good round for Elk.

I thought that I seen it all, and I found out today that I haven't seen anything.

What you have there is some sort of parting blade.

You didn't say what type of parting blade it is, what materials it is made out of, what lathe you plan to use it with, how many horsepower it is, what tool holder you plan to use to hold it.

For all I know, you are going to hold it in your hand and run the lathe at 1000 rpms.

I guess my 4 years working in machine shops and 2 years of accumulated school time was all for nothing. All I had to do was buy a lathe and some tools and it would automatically make me into a machinist.

Also having read several books on the subject including the Machinist Bedside Reader, might give me just enough knowledge not to post on this subject.

A lathe, a live center, a 3 jaw chuck, a parting blade - made out of High Speed Steel and some cutting oil isn't all that is needed to work on rifle barrels.

Yes, a parting blade is made for cutting materials of lesser hardness than the blade.

Some stainless steels are harder than your blade. Even in a good machine shop with good machines and good tooling it is hard to cut. The tool sometimes has a tendency to skate across the material and will work harden the material that you are trying to cut and will actually do more damage than good.

Then you have to get into basic tool room knowledge - such as cutting and facing tools. You have right hand cutting and right hand facing and you have left hand cutting and left hand facing.

Then you have HSS - High speed steels, Ceremets, basic sinitered cutting tools, CBN. PCBN, I could write a list as long as my arm.

Then you still have to have a knowledge of machining, such things as speeds and feeds, surface feet per a minute of feed, threading, back gears, cutting on tapers etc.

Even a good book isn't going to make you into a machinist.

With the price of steel right now, round stock, square stock, odd pieces of steel and a cut off wheel and a band-saw will run into thousands of dollars.

Even with all that, you will still need a Bridgeport Mill and all the tooling for that and a pedestal grinder. Different grits of wheels and different types of wheels for shaping and honing some of your cutting tools.

I hope you have fun working on guns. It is going to be a very expensive hobby.

WILDCATT · « **Reply #4 on:** January 03, 2008, 02:04:10 PM »

Gamemaster: that was an awful thing to say to a new machinist.why he hardly has started wait til he cuts off a finger or puts an eye out when the blade snaps.MY GOD ITS AS BAD AS RELOADING WITH OUT A CLUE.WENTWORTH GRADUATE MACHINE AND TOOLMAKER.job shop machinist 7yrs.13 yrs in Ratheon machine shop.he should take a night course at least.

Les Brooks · « **Reply #5 on:** January 03, 2008, 03:32:17 PM »

Handi,
The cutoff tool that I tried on my small lathe caused trouble hanging up. Too much springing of the bed. Always ware safety glasses when working on any machine in case a chip comes after you. The chinese drills that I have used will cut over size holes most of the time. I have one set that drills very well that I bought at TSC. The rifle in the picture was barreled on a 7X12 Grizz and milled with the HF minimill. Remember that these are for mostly for a hobby.

Les Brooks · « **Reply #6 on:** January 03, 2008, 03:52:51 PM »

Here is the other half!!! I forget to include it above.

handirifle · « **Reply #7 on:** January 03, 2008, 04:37:18 PM »

Wow! never meant to imply anything or act like I was a machinist. Some of you guys need to lighten up. A simple NON DEMEANING answer would have sufficed. I'm FULLY aware a night class or day class or working with a machinist, all would be prefferable to the way I'm doing it, but as stated, currently I have no option. I work 2 nights a week and the three days shifts are variable in hours.

After 25 years as an Air Traffic Controller, and I'm a master at my work as well, I'd never talk that way to someone asking about my job. I'm sure many on this board are also clueless to my job, but I'd be HAPPY to inform them of how it works. The reason is I understand most have no idea how my work is done. No, I do not work at an airport, neither do the other 300 controllers in my building, but most likely I have handled the plane any one of you has flown in, and done it without killing anyone.

I resent being treated like an imbecile. I was simply asking for some advice. Did I expect to become a "machinist" form this forum? No!

That said, even as dumb and ignorant as I am, I knew beforehand I needed a holder, so I also got this one.

This is the spec on the cutting blade. 1/16" x 1/2" x 4-1/2" M2 HSS cut-off blade.

Thanks for the info, maybe I'll look for info at a friendlier location.

The Gamemaster · « **Reply #8 on:** January 03, 2008, 05:04:23 PM »

Nothing said here was meant to be demeaning or out of context.

What we are saying is not to machine anything on the lathe that you bought until you get the proper training and also practice on something other than guns.

I have machined rolls on a lathe for steel mills that were 40 FEET long and 36 INCHES in diameter that was Rockwell C - 52 in hardness, where it took 4 hours to make one cut 2.5 thousandths - .0025 off the part - because that was all the more the cutting tool would allow, without snaping off.

I myself, won't machine on a gun on a home shop lathe - because it just isn't precision enough.

I didn't want you to get mad, I just wanted to make sure that you didn't do anything foolish that ended up in injury or death.

I have snapped off dozens of parting blades, running them too fast, using the wrong coolant, hitting the workpiece and doing damage Lot's of times. What you have there is a common mistake that is made amongst first time lathe buyers that has no experience running machine tools.

I wouldn't be able to do your job, even if you stood beside me, and if you did let me do your job, it would be criminal. The same thing about my occupation - if I just stood you beside the machine and told you what to do and you made a mistake, it would be my fault - for not training you the proper way to do it and not supervising you until you acquired enough knowledge to do it yourself.

I don't want to see you butcher any of your guns - just so you can learn how to machine on guns.

By the time you learned how to put the proper crown on the end of the barrel, it would be 6 inches long.

Then there are such things as deburring tools and grinders and tool post grinders and Morse tapers and one thousand other things that you will have to learn about before you get good enough to do it yourself.

Just take it slow and get Lot's of practice on scrap material before you try to start doing any serious machining.

burntmuch · « **Reply #9 on:** January 03, 2008, 05:24:14 PM »

Geez I just took a hacksaw to my barrel & recrowned with a dremil bit. I guess I should have went to school for 10 yrs before trying something like that. silly me. Handirifle , I hope someone whos not a miserble prick answers some of your questions, & good luck. Jay

The Gamemaster · « **Reply #10 on:** January 03, 2008, 05:30:33 PM »

Phoneman · « **Reply #11 on:** January 04, 2008, 12:51:06 AM »

I cut a barrel with a hacksaw and recrowned it useing tools from brownels. cost about 200 bucks for the tools and since then I have bought different pilots and done many other guns for people. If I had the extra money I would buy a lathe and try it. Handirifle I have an extra barrel from a ruger 10/22 I'll send you if you would like it to practice on. Free of charge. Good luck with your venture.

Les Brooks · « **Reply #12 on:** January 04, 2008, 03:11:29 AM »

This is a gunsmithing forum and not a machinist forum!! I do not get on these forums to show how much I don't know but to share my experiences as a full time gunsmith. After over 40 years as a gunsmith this is what I hear from most guys that work as a machinist. If you guys would go and work for a gun shop you would find that most machines will not hold to production tolerances. An old machine will do gun jobs as each operation is a seperate set up.

If Handi wants to start learning this trade as a hobby there are several people on this forum that will tell or show how they worked.

Handi I have pictures of my set up for barrelling with these small lathes. I also made a mold for casting small bullets and the sizing dies. Keep on learning and you will have many hours of fun making new tools or guns.

The above stock was duplicated on a machine that I built in 1983. A 40 year machinist told people that my machine would not be good enough to use on custom stocks. He had a factory built machine and cut stocks for the trade. This guy could run a machine, but couldn't make a stock look like a professional job.

Smokin Joe · « **Reply #13 on:** January 04, 2008, 04:18:58 AM »

Handi, it sure sounds like you took a ration of crap for a simple question.

Yep, the cutoff should work fine for bullets and probably for barrel steel as well. I've done it that way using a steady rest. As for crowning, the simple way is to rent a crowning tool from 4-D or set the barrel up in a steady rest and just use a carbide bit to cut an 11 degree crown.

Awf Hand · « **Reply #14 on:** January 04, 2008, 08:28:48 AM »

That was way more than a ration of crap...

Since it seems that some here feel you should have several hundred bucks in measuring tools to turn the noses off bullets, feel free to PM me if you have questions getting started. We'll get you going. The biggest hurdle is the language. Headstock, tailstock, ways, gibs, carriage, collets, rake... it's like learning nautical (or in your case, aviation) terms. ANYTHING that can be taught in a one night a week 6 week class can be learned by picking up the right book and reading and applying what you've just read. If you run into issues, ask here. You might have to sort through the posts and the whole *I went to school for machine tools and you couldn't possibly teach yourself* BS, but I and others like me will be here. You've been working in an upper-end-education-required profession for awhile, so you know what your limits are.

The CO tool and holder that you bought should work fine. Just be sure to put a good cutting edge on it which is suited to the soft material you're cutting.

I have a book that I can maybe scan and e-mail to you. (out of print for over 50 years and publishing company is gone too) It shows how to sharpen machine cutting bits for lathes/shapers and the like.

For now, learn enough to know what you don't know, then start filling in blanks as needed.

Above all, work safe! Machines don't know meat from metal.

gunnut69 · « **Reply #15 on:** January 04, 2008, 10:04:19 AM »

Sorry guys.. I've been a bit scarce of late and the Gamemaster is again acting up. His tirades tend to feature him extolling his knowledge and your lack.. If he continues I will have to handle the situation. LesBrooks information is good. One doesn't have to be a machinist toe be a gunsmith but some knowledge is necessary. We can't make you a gun smith but we can answer questions and make observations to try and keep you out of harms way. You will make mistakes and learning is never free. You will gain knowledge and skill. Some folks already know it all.. If the situation continues or anyone feels the need to vent contact me thru GB as my email is not working..

handirifle · « **Reply #16 on:** January 05, 2008, 07:56:03 AM »

Thanks guys, thanks to you and others I've come back and do appreciate the "real info" offered. I have printed out the material from this site, http://www.mini-lathe.com/ about 60 pages worth and I'm learning a LOT. I had this printed before posting here. I'll try to find info as much as possible before posting any more "stupid"

questions.

bluebayou · « **Reply #17 on:** January 05, 2008, 06:01:47 PM »

Wow, and I thought that he talked to me like I was an idiot about the hickory the other day.

Handirifle, I cut an SKS with hacksaw and then faced it with machinist square and a file. It took walking away from it a few times to get it square. It is not crowned. It shoots fine....for now. I hope to get enough money for Brownells tools.

http://www.brownells.com/aspx/ns/store/catsearch.aspx?c=1221&p=4810

http://www.brownells.com/aspx/ns/store/catsearch.aspx?c=1219&p=4810

In a fit of laziness/ingenuity, I used an abrasive cutoff wheel to cut a 12 gauge barrel. I cut the barrel at my 18-1/2" mark. Then I put a 4-1/2" air grinder in a vise and leveled it with........a level. Then made jig with scrap wood to hold barrel parallel to workbench. Outside counter of barrel was not straight. Barrel tapered to muzzle so it took a little work. Then faced new muzzle to roughly 90 degrees with light pressure pushing against powered up grinder.

bluebayou · « **Reply #18 on:** January 05, 2008, 07:20:38 PM »

If you like that Mini-lathe site, check this out. A lot of interesting info about surface prep for metals.

http://www.bestofblasting.com/

The site is slow and you have to click on the black dots to load topics.

handirifle · « **Reply #19 on:** January 05, 2008, 07:55:55 PM »

Well I have the means to effeciently cut it but was just wondering how others did it.

Awf Hand · « **Reply #20 on:** January 06, 2008, 09:38:38 AM »

I've done rebarreling and used a power hack to cut off the bbl. After truing in the lathe (quite a process to get full length runout nearest zero as possible) and setting a steady rest, the compound was set to pull 11degrees across the face from the muzzle out on the sawcut end. It turned quite well, and looks as nice as any would.
My best finish was a second in our regional, but that was the only match I've fired with this gun.