new to gunsmithing I just got a 11in logan lathe cany anyone send me detail steps and pictures on how to cut a barrel down to 18in and recrown thanks
Gunsmithing cutting a barrel
- Thread starter specopsbrooklyn
- Start date
Re: cutting a barrel
Different people have different expectations on what a crown should look like and the perfect way to do it.
There are people on here better suited to answer the question than me.
But if you feel like it, try this
Just cut the barrel off at 18.25", face it off, cut the crown shape you want, then use one of those 45Degree piloted hand crowning tools from Brownells to touch it. You could use one of those brass crown lapping tools but I think the piloted tool would be better.
Never used either one so let me know how it comes out if you do it
Different people have different expectations on what a crown should look like and the perfect way to do it.
There are people on here better suited to answer the question than me.
But if you feel like it, try this
Just cut the barrel off at 18.25", face it off, cut the crown shape you want, then use one of those 45Degree piloted hand crowning tools from Brownells to touch it. You could use one of those brass crown lapping tools but I think the piloted tool would be better.
Never used either one so let me know how it comes out if you do it
Re: cutting a barrel
AZPrecision's method will work just fine, my one suggestion is to make the final facing pass from the center of the bore to the OD, this will keep the muzzle from developing a burr during the final pass.
This also means that you don't need to put a chamfer on the bore exit, if you want to, have a ball. Just be sure not to leave a burr on the muzzle.
Macssubmoa was keen to explain the final pass trick to me.
EDIT: One more thing, I'm not overly keen on the idea of a solid pilot cutting tool in teh bore, especially at the muzzle. If you want to put a slight corner break on the muzzle I'd suggest doing it with a touch countersink while it is still centered in the lathe, hold the tool with the tailstock chuck.
AZPrecision's method will work just fine, my one suggestion is to make the final facing pass from the center of the bore to the OD, this will keep the muzzle from developing a burr during the final pass.
This also means that you don't need to put a chamfer on the bore exit, if you want to, have a ball. Just be sure not to leave a burr on the muzzle.
Macssubmoa was keen to explain the final pass trick to me.
EDIT: One more thing, I'm not overly keen on the idea of a solid pilot cutting tool in teh bore, especially at the muzzle. If you want to put a slight corner break on the muzzle I'd suggest doing it with a touch countersink while it is still centered in the lathe, hold the tool with the tailstock chuck.
Re: cutting a barrel
there are several methods to set up a barrel in a lathe to cut and crown a barrel. some methods make more sense to me but you may be limited to other ways depending on limitations of you lathe. there are a couple links to builds in my signature that include pictures and description of how i set up barrels in the lathe. i use the same setup for chamber and crown work.
there are several methods to set up a barrel in a lathe to cut and crown a barrel. some methods make more sense to me but you may be limited to other ways depending on limitations of you lathe. there are a couple links to builds in my signature that include pictures and description of how i set up barrels in the lathe. i use the same setup for chamber and crown work.
Re: cutting a barrel
Thats not my method. Figured it'd work but I was just asking him to try
There's no method that's mine just yet.
And the pilot is brass. It wont hurt nothin.
Thats not my method. Figured it'd work but I was just asking him to try
There's no method that's mine just yet.
And the pilot is brass. It wont hurt nothin.
Re: cutting a barrel
I take the barreled action and cover the barrel with blue painters tape up to a point about 1.5" short of where I want to cut off the barrel.
Then I set the barrel thru the headstock with the tape even with the jaws on the 4 jaw chuck. Use a live center in the tailstock and put the muzzle (bore) onto the live center.
While pushing the barreled action from the receiver end onto the live center, adjust the jaws on the chuck to just touch the barrel. Then snug up the jaws(but on't over tighten yet).
Then I snug up the spider chuck on the chamber end of the barrel.
I remove the tailstock and insert a caliber specific range rod into the bore. Using a dial indicator that reads 0.001" increments I adjust the chuck jaws to get < 0.0005" ( half a thousandth) run out on the range rod.
Now you're ready to cut. With your tool post set perpendicular to the barrel use a cut off tool to seperate the barrel about 0.050" longer than where you want the final length.
Then mount a single point cutting tool and face off the end of the barrel from the outside in to the bore. I usually make 2 passes with the final pass only taking about 0.001" to 0.002".
Now I set the tool post to an 11 degree cut and use the tool post turret feed to make the 11 degree crown cut. I feed the tool very slow and use plenty of lube. I start the cut about 0.050" from the outside edge and cut toward the bore.
Your cutting is done at this point. I move the cross slide out of the way and spin the barrel at about 300-400 rpm. I then take a fine tooth finish file to the very end of the outside edge of the barrel to remove any burr.
Finally I use 80, 120,240,400, and 800 grit wet n dry to polish the crown ( this process removes any burr on the bore). When I'm satisfied with the finish I do 0000 steel wool to make it shine.
Like others have stated, there are many ways to do this, this is just the way I do it.
Good Luck.
I take the barreled action and cover the barrel with blue painters tape up to a point about 1.5" short of where I want to cut off the barrel.
Then I set the barrel thru the headstock with the tape even with the jaws on the 4 jaw chuck. Use a live center in the tailstock and put the muzzle (bore) onto the live center.
While pushing the barreled action from the receiver end onto the live center, adjust the jaws on the chuck to just touch the barrel. Then snug up the jaws(but on't over tighten yet).
Then I snug up the spider chuck on the chamber end of the barrel.
I remove the tailstock and insert a caliber specific range rod into the bore. Using a dial indicator that reads 0.001" increments I adjust the chuck jaws to get < 0.0005" ( half a thousandth) run out on the range rod.
Now you're ready to cut. With your tool post set perpendicular to the barrel use a cut off tool to seperate the barrel about 0.050" longer than where you want the final length.
Then mount a single point cutting tool and face off the end of the barrel from the outside in to the bore. I usually make 2 passes with the final pass only taking about 0.001" to 0.002".
Now I set the tool post to an 11 degree cut and use the tool post turret feed to make the 11 degree crown cut. I feed the tool very slow and use plenty of lube. I start the cut about 0.050" from the outside edge and cut toward the bore.
Your cutting is done at this point. I move the cross slide out of the way and spin the barrel at about 300-400 rpm. I then take a fine tooth finish file to the very end of the outside edge of the barrel to remove any burr.
Finally I use 80, 120,240,400, and 800 grit wet n dry to polish the crown ( this process removes any burr on the bore). When I'm satisfied with the finish I do 0000 steel wool to make it shine.
Like others have stated, there are many ways to do this, this is just the way I do it.
Good Luck.
Re: cutting a barrel
I haven't posted but a few on here. If your Logan lathe won't except the barrel through the spindle, You'll need to set up a steady-rest and dial in the barrel. Since you are cutting down the length use a live center in the tailstock inserted into the barrel tip to align the barrel in the steady-rest. Cut the barrel about .050 longer with a nice sharp tool, I prefer Carbide. Then face off the remainder and as Bohem suggest take your last cut from the inside and feed out. I usually set my compound at 5 ½ degrees to get a total of 11 degree crown then I slightly recess the crown to prevent any damage if the barrel tip is bumped. Finally I polish it to a mirror finish. I've seen many different ways to crown a barrel, this technique has worked for me on many rifles. Take your time and you'll do fine.
I haven't posted but a few on here. If your Logan lathe won't except the barrel through the spindle, You'll need to set up a steady-rest and dial in the barrel. Since you are cutting down the length use a live center in the tailstock inserted into the barrel tip to align the barrel in the steady-rest. Cut the barrel about .050 longer with a nice sharp tool, I prefer Carbide. Then face off the remainder and as Bohem suggest take your last cut from the inside and feed out. I usually set my compound at 5 ½ degrees to get a total of 11 degree crown then I slightly recess the crown to prevent any damage if the barrel tip is bumped. Finally I polish it to a mirror finish. I've seen many different ways to crown a barrel, this technique has worked for me on many rifles. Take your time and you'll do fine.
Re: cutting a barrel
The crown on your rifle is extremely important to accuracy. So if you want excellent results, here is one way. If it is a bolt gun you need to dive it with a tight fitting mandrel through the action in the lathe. Set up your steady rest as close as possible to the muzzle and still be able to set up a parting tool. Use your live center in the muzzle to center the barrel so it will run as true as possible. Keep in mind that the outside of your barrel is not concentric to your bore which your live center is in right at this point. I say this so when you adjust your steady on the barrel, do it just enough to support the barrel. I do not know your level of machining, but now you need to set up your parting tool square with the work. Set your lathe to its slowest speed, using a good grade of cutting oil, lube the work and cut off the barrel where you want. This is a slow process, and use plenty of lube. WD 40 is not cutting oil, nor is motor oil. Now the important part. The best way is to purchase a crowning tool for the specific caliber range and a set of removable bushings. Select the a bushing from the set that fits snug but not tight. Install it in a floating holder and insert the holder in the tail stock after you remove the live center you had there before. Using very high quality cutting oil, very slow RPM on your lathe, cut your crown deep enough to face across the whole muzzle. Now using a 60 degree center on that same snug fitting bushing, held in a tee handle supported by the dead center in your tail stock, make an inward cut by hand of about .010" to break the sharp edge which will prevent damage to your crown. Examine your work with a good set of magnifiers 25 power or so. If you wish, you may lapp the crown to a polished finsh, but not really needed if you did a great job in cutting using the proper tools and fluid. If you decide to go this route, the tools can be purchased from PTG or JGS, both makers of high quality tools and very helpful if you call them direct. At JGS speak with Cary, and at PTG speak with Dave. Either of these guys are about the nicest most helpful guys you want to meet, which I have met in person at the 2009 shot show. If you went to the expence of buying a lathe, get ready to start spending some serious money on tooling. No I am NOT advertising for these guys. I have bought and tried a lot of products, and am trying to save you from wasting your money and ending up disappointed. For all of you with a different way and opinion, just let me say there are different ways to go about doing anything, and I respect them all. This is my way, and if done properly, you will be very satisfied. Good luck, and I wish you good results any way you try it.
The crown on your rifle is extremely important to accuracy. So if you want excellent results, here is one way. If it is a bolt gun you need to dive it with a tight fitting mandrel through the action in the lathe. Set up your steady rest as close as possible to the muzzle and still be able to set up a parting tool. Use your live center in the muzzle to center the barrel so it will run as true as possible. Keep in mind that the outside of your barrel is not concentric to your bore which your live center is in right at this point. I say this so when you adjust your steady on the barrel, do it just enough to support the barrel. I do not know your level of machining, but now you need to set up your parting tool square with the work. Set your lathe to its slowest speed, using a good grade of cutting oil, lube the work and cut off the barrel where you want. This is a slow process, and use plenty of lube. WD 40 is not cutting oil, nor is motor oil. Now the important part. The best way is to purchase a crowning tool for the specific caliber range and a set of removable bushings. Select the a bushing from the set that fits snug but not tight. Install it in a floating holder and insert the holder in the tail stock after you remove the live center you had there before. Using very high quality cutting oil, very slow RPM on your lathe, cut your crown deep enough to face across the whole muzzle. Now using a 60 degree center on that same snug fitting bushing, held in a tee handle supported by the dead center in your tail stock, make an inward cut by hand of about .010" to break the sharp edge which will prevent damage to your crown. Examine your work with a good set of magnifiers 25 power or so. If you wish, you may lapp the crown to a polished finsh, but not really needed if you did a great job in cutting using the proper tools and fluid. If you decide to go this route, the tools can be purchased from PTG or JGS, both makers of high quality tools and very helpful if you call them direct. At JGS speak with Cary, and at PTG speak with Dave. Either of these guys are about the nicest most helpful guys you want to meet, which I have met in person at the 2009 shot show. If you went to the expence of buying a lathe, get ready to start spending some serious money on tooling. No I am NOT advertising for these guys. I have bought and tried a lot of products, and am trying to save you from wasting your money and ending up disappointed. For all of you with a different way and opinion, just let me say there are different ways to go about doing anything, and I respect them all. This is my way, and if done properly, you will be very satisfied. Good luck, and I wish you good results any way you try it.
Re: cutting a barrel
thanks for all the great info at least now I have some good ideas
thanks for all the great info at least now I have some good ideas
Re: cutting a barrel
So another question arises....
When you cut your barrel down do you have to cut it to any certain spot? Are you looking for a particular area to cut? There is a machine shop Ive used for a while now that does excellent threading work and small parts work. They offered to cut down my barrel for me but use a different method.
And when I cut down the barrel and re thread for a QD mount, for a suppressor, will I need to recrown or does it matter since the QD mount is going on? I am trying to learn to do my own threading and stuff so all this info really helps. thanks guys
So another question arises....
When you cut your barrel down do you have to cut it to any certain spot? Are you looking for a particular area to cut? There is a machine shop Ive used for a while now that does excellent threading work and small parts work. They offered to cut down my barrel for me but use a different method.
And when I cut down the barrel and re thread for a QD mount, for a suppressor, will I need to recrown or does it matter since the QD mount is going on? I am trying to learn to do my own threading and stuff so all this info really helps. thanks guys
Re: cutting a barrel
You don't necessarily HAVE to cut to a specific spot according to many streams of thought. If you subscribe to the thoughts of barrel harmonics though and care to worry about it for a specific combination you can try to get close to an antinode as the crown.
You can just stick a tuning collar on it if you feel the need to go for this method. I'd personally just cut it back to the specified length you want and take good care for a good crown.
I really need to go to bed so I'll skip my direct thoughts on barrel length harmonics for a specific bullet. It's theoretically a great thing and I hope to someday have enough time to try it on a dedicated barrel. In practicum it's not realistic.
No matter how you slice it though, the barrel must have a proper crown around the bore exit. If youre putting a permanent QD mount on it that crown can be as simple as a proper cutoff, thread and final facing job with or without a corner break as mentioned above.
You don't necessarily HAVE to cut to a specific spot according to many streams of thought. If you subscribe to the thoughts of barrel harmonics though and care to worry about it for a specific combination you can try to get close to an antinode as the crown.
You can just stick a tuning collar on it if you feel the need to go for this method. I'd personally just cut it back to the specified length you want and take good care for a good crown.
I really need to go to bed so I'll skip my direct thoughts on barrel length harmonics for a specific bullet. It's theoretically a great thing and I hope to someday have enough time to try it on a dedicated barrel. In practicum it's not realistic.
No matter how you slice it though, the barrel must have a proper crown around the bore exit. If youre putting a permanent QD mount on it that crown can be as simple as a proper cutoff, thread and final facing job with or without a corner break as mentioned above.
