C
chris k
Guest
Wondering what method guys are using for holding reamer and why they use that system ; I have used the JGS floater ,clymer floater ,the center in the tailstock and the 3 jaw jacobs chuck .
Chris
Chris
JerrySharrett
Senile Member
Most of those cheap floaters don't float. A good horizontal floater will cost $400-$500. Many are now using a floating pusher. Do a search in the gunsmith forum of this site for floating pushers.
JerrySharrett
Senile Member
N
NesikaChad
Guest
Try the carriage?
J
Joel
Guest
I use an industrial floating reamer holder in the tool post. I haven’t used the tailstock for reaming for at least 15 years. If you have a DRO I recommend using the carriage to chamber ream.
C
chris k
Guest
method
Please explain the carriage method you use .
thx,
Chris
Please explain the carriage method you use .
thx,
Chris
N
NesikaChad
Guest
It goes like this:
Obtain whatever reamer hold your going to use. Make it, buy it, whatever. It becomes arbitrary with this method.
with the holder in place square it up with your spindle. The easy way to start is just by eye balling it or pushing it up against the chuck with the tool post nice and loose.
Cinch her down.
Take a dead center and stick it between the point on the reamer holder and the breech of the barrel. Use a little pressure so that it holds it still. Now either make/buy an indicator with a C clamp and clamp down on the dead center. If you really wanna get fancy, drill/tap the dead center for an indicator post and screw it in directly.
Here's the part to pay attention to. You have to make a "thingy" that will clamp onto one of your chucks jaws. It should extend as far away from the chuck as you can get it without it smacking the bed of the lathe. The further the better.
Your indicator post needs to be able to extend as far as it can without banging the bed also.
Set your indicator to contact the "thingy" mounted to the chuck jaw. Now slowly rotate over a complete circle. You'll quickly learn that you'll have to position your cross slide to get the "X" axis right. For the "Y" axis you then adjust the tool height on your tool holder/tool post.
The further you are from center, the more amplified any deviation is going to be; which translates into improved accuracy potential for centering the reamer holder. It'll be a little dramatic the first time, but with a little practice it comes quickly.
I suggest using an indicator with a .001" resolution. You can go to tenths but if you get way out there you'll be working in gillionths anyway so it gets to the point of being silly at some point.
Just sweep the circumference and keep bouncing your position back and forth until the needle on the indicator sits still the whole time.
Now mount your tool and let it rip.
Advantages:
If you have a DRO then cutting depths become a snap. Plunge, note the position, retract, plunge to within .01" of last depth, and then plunge again. Or you can just zero the DRO at each depth and work incrementally. Whatever is easiest.
You have good control with the big carriage wheel.
You get to use both hands. (vs the tap wrench method)
You have more mass in the carriage and this means improved surface finishes. I keep seeing intermittent posts here/there regarding chatter. The definition of insanity is to repeat the same thing over and over with the expectation of having a different end result. If you start to hear the reamer squeal with this method, increase the feed rate and it'll go away. Same as any other machining operation. You either decrease the RPM or increase the feed.
You can feel what the tool is doing better than the tailstock (my opinion)
You don't have to dicker around with the tail stock being out of alignment, off axis, etc.
You have total control to determine the center point of both the X and the Y axis. Your not at the mercy of shims or the guy who put the machine together.
Disadvantages:
You bump that cross slide or compound your going to ruin your barrel.
It takes a bit longer to set up (at first, with practice and after taking the time to make dedicated set up tooling, it goes very quickly)
It goes against alot of conventional wisdom which can get odd looks/comments from others. (I live for this, so I don't care)
Results:
It's too easy to get into a chest beating seminar; which results in irritated egos and yada yada. I will tell you that I've been doing it this way since 2003. I've done it manually and with a CNC. My holder for my CNC is special in that I had to get creative with how I made the holder since it has a turret instead of a tool post. I figured it out and it works wonderfully. My chambers are very round, very concentric, and my surface finishes are good too. The guns shoot well and clients have big smiles.
Try it out, see what you think.
Measure twice, cut once.
All the best,
C
Obtain whatever reamer hold your going to use. Make it, buy it, whatever. It becomes arbitrary with this method.
with the holder in place square it up with your spindle. The easy way to start is just by eye balling it or pushing it up against the chuck with the tool post nice and loose.
Cinch her down.
Take a dead center and stick it between the point on the reamer holder and the breech of the barrel. Use a little pressure so that it holds it still. Now either make/buy an indicator with a C clamp and clamp down on the dead center. If you really wanna get fancy, drill/tap the dead center for an indicator post and screw it in directly.
Here's the part to pay attention to. You have to make a "thingy" that will clamp onto one of your chucks jaws. It should extend as far away from the chuck as you can get it without it smacking the bed of the lathe. The further the better.
Your indicator post needs to be able to extend as far as it can without banging the bed also.
Set your indicator to contact the "thingy" mounted to the chuck jaw. Now slowly rotate over a complete circle. You'll quickly learn that you'll have to position your cross slide to get the "X" axis right. For the "Y" axis you then adjust the tool height on your tool holder/tool post.
The further you are from center, the more amplified any deviation is going to be; which translates into improved accuracy potential for centering the reamer holder. It'll be a little dramatic the first time, but with a little practice it comes quickly.
I suggest using an indicator with a .001" resolution. You can go to tenths but if you get way out there you'll be working in gillionths anyway so it gets to the point of being silly at some point.
Just sweep the circumference and keep bouncing your position back and forth until the needle on the indicator sits still the whole time.
Now mount your tool and let it rip.
Advantages:
If you have a DRO then cutting depths become a snap. Plunge, note the position, retract, plunge to within .01" of last depth, and then plunge again. Or you can just zero the DRO at each depth and work incrementally. Whatever is easiest.
You have good control with the big carriage wheel.
You get to use both hands. (vs the tap wrench method)
You have more mass in the carriage and this means improved surface finishes. I keep seeing intermittent posts here/there regarding chatter. The definition of insanity is to repeat the same thing over and over with the expectation of having a different end result. If you start to hear the reamer squeal with this method, increase the feed rate and it'll go away. Same as any other machining operation. You either decrease the RPM or increase the feed.
You can feel what the tool is doing better than the tailstock (my opinion)
You don't have to dicker around with the tail stock being out of alignment, off axis, etc.
You have total control to determine the center point of both the X and the Y axis. Your not at the mercy of shims or the guy who put the machine together.
Disadvantages:
You bump that cross slide or compound your going to ruin your barrel.
It takes a bit longer to set up (at first, with practice and after taking the time to make dedicated set up tooling, it goes very quickly)
It goes against alot of conventional wisdom which can get odd looks/comments from others. (I live for this, so I don't care)
Results:
It's too easy to get into a chest beating seminar; which results in irritated egos and yada yada. I will tell you that I've been doing it this way since 2003. I've done it manually and with a CNC. My holder for my CNC is special in that I had to get creative with how I made the holder since it has a turret instead of a tool post. I figured it out and it works wonderfully. My chambers are very round, very concentric, and my surface finishes are good too. The guns shoot well and clients have big smiles.
Try it out, see what you think.
Measure twice, cut once.
All the best,
C
C
chris k
Guest
thanks,
chris
chris
I
IndianaJames
Guest
Chad...
I got most of that, but still a little unsure about the "thingy" thingy. Would it be correct to say that the dead center, with the indicator clamped to it and in contact with the thingy, is rotated along with the chuck giving a continuous indication, using the top and bottom readings to adjust the height of the holder, and the fore and aft to adjust the crossfeed?
I think I like it.
Jim
I got most of that, but still a little unsure about the "thingy" thingy. Would it be correct to say that the dead center, with the indicator clamped to it and in contact with the thingy, is rotated along with the chuck giving a continuous indication, using the top and bottom readings to adjust the height of the holder, and the fore and aft to adjust the crossfeed?
I think I like it.
Jim
N
NesikaChad
Guest
I need to make a correction on my earlier post:
The reamer holder is not "arbitrary" as I stated earlier. I take it back and apologize for stating something so blatantly stupid.
Anyone who spends any amount of time around a machine shop should quickly learn that a fundemental principle for producing good work depends heavily on two things: Good work holding and good tooling.
In a mill we like big heavy vises and carbide endmills. The vise provides rigid clamping, and the carbide is as stiff as a 16 year old after the prom. Working together these two combine for improved finishes and more accurate parts.
Using this train of thought, a tool holder with mass makes sense to me. The one I made is a rather robust contraption made from 5" OD 4140 heat treat. It alone weighs about 9lbs. Maybe it's overkill. All I know is I've yet to have a squeak, a squeal, or any sort of beaver tooth mark appear in a chamber. Things are very quiet, calm, and methodical as that tool chews through steel. I run my RPM at close to 400 sometimes depending on the diameter of the reamer. Small tool='s more speed to get my desired surface footage/minute.
I know folks use a tap handle and make nice n pretty chambers. I've done it this way too and it was a gift I never received. After the 3rd time of having the tool grab, making the webs between my fingers look like I bought season tickets to the piranha petting zoo, I gave up and sought another way.
What you can take from this is good machine work, whether its on the space shuttle or a rifle, is nothing more than careful diligent application of fundamentals.
Ok, onto your question:
The "thingy" can be as crude as a "kant twist" clamp or as exotic as a guy wants to make it.
I use a 16C indexable collet closer on my HTC. My "thingy" is a "kant-twist" clamp that goes around the spindle nose. I stick my indicator stylus up by the T handle that tightens the clamp. All your after is something to increase the swept diameter of the chuck. Long as possible without banging into your bed.
The dead center should not be allowed to swing on it's own. You want it to "bite" the breech so that the barrel drives it (rotates it) The indicator, dead center, and the "thingy" should all rotate as one unit. With the CNC it's easy because when you jog the turret to a position it holds that position no matter what. A manual carriage is a little more work because you have to maintain some pressure.
A few more points to ensure:
If your lathe is old/worn in the bedway right in front of the chuck you may have problems as the carriage is going to be inclined to move in "Y" as it traverses in "Z". If your machine has seen its day then this may not be the way to go.
If you can lock your carriage down with a gib lock as your setting up then this works great. Set your compound parallel to the Z axis and use it to fine tune the pressure. BUT once you think you got it, check it again with the gib locks released and use just an even hand pressure.
Don't get carried away with the pressure on the center as it can try to lift the carriage away from the bed. You want just enough to hold it. A dab of coarse lapping compound on the dead center nose can help to get a good bite on the breech if your having trouble. Just be sure to sterilize everything before chambering. That'd make one hell of a mess inside the bore!
I suggest getting a scrapper barrel and getting the feel for it that way first. Once you have it down pat, it's really very simple and I do think (personal opinion) that it offers the potential for better finishes/accuracy/concentricity.
One last little nibble:
We know barrels aren't straight right? Range rods, Ouiji boards, and hair of newt is all good. If given a choice about WHERE (that's a hint) to indicate a barrel, ask yourself as you brush your teeth where exactly that spot would be and how would one go about indicating that particular location.
Answer that and you might just get a wee bit smaller next time your at the range.
Good luck.
All the best,
C
The reamer holder is not "arbitrary" as I stated earlier. I take it back and apologize for stating something so blatantly stupid.
Anyone who spends any amount of time around a machine shop should quickly learn that a fundemental principle for producing good work depends heavily on two things: Good work holding and good tooling.
In a mill we like big heavy vises and carbide endmills. The vise provides rigid clamping, and the carbide is as stiff as a 16 year old after the prom. Working together these two combine for improved finishes and more accurate parts.
Using this train of thought, a tool holder with mass makes sense to me. The one I made is a rather robust contraption made from 5" OD 4140 heat treat. It alone weighs about 9lbs. Maybe it's overkill. All I know is I've yet to have a squeak, a squeal, or any sort of beaver tooth mark appear in a chamber. Things are very quiet, calm, and methodical as that tool chews through steel. I run my RPM at close to 400 sometimes depending on the diameter of the reamer. Small tool='s more speed to get my desired surface footage/minute.
I know folks use a tap handle and make nice n pretty chambers. I've done it this way too and it was a gift I never received. After the 3rd time of having the tool grab, making the webs between my fingers look like I bought season tickets to the piranha petting zoo, I gave up and sought another way.
What you can take from this is good machine work, whether its on the space shuttle or a rifle, is nothing more than careful diligent application of fundamentals.
Ok, onto your question:
The "thingy" can be as crude as a "kant twist" clamp or as exotic as a guy wants to make it.
I use a 16C indexable collet closer on my HTC. My "thingy" is a "kant-twist" clamp that goes around the spindle nose. I stick my indicator stylus up by the T handle that tightens the clamp. All your after is something to increase the swept diameter of the chuck. Long as possible without banging into your bed.
The dead center should not be allowed to swing on it's own. You want it to "bite" the breech so that the barrel drives it (rotates it) The indicator, dead center, and the "thingy" should all rotate as one unit. With the CNC it's easy because when you jog the turret to a position it holds that position no matter what. A manual carriage is a little more work because you have to maintain some pressure.
A few more points to ensure:
If your lathe is old/worn in the bedway right in front of the chuck you may have problems as the carriage is going to be inclined to move in "Y" as it traverses in "Z". If your machine has seen its day then this may not be the way to go.
If you can lock your carriage down with a gib lock as your setting up then this works great. Set your compound parallel to the Z axis and use it to fine tune the pressure. BUT once you think you got it, check it again with the gib locks released and use just an even hand pressure.
Don't get carried away with the pressure on the center as it can try to lift the carriage away from the bed. You want just enough to hold it. A dab of coarse lapping compound on the dead center nose can help to get a good bite on the breech if your having trouble. Just be sure to sterilize everything before chambering. That'd make one hell of a mess inside the bore!
I suggest getting a scrapper barrel and getting the feel for it that way first. Once you have it down pat, it's really very simple and I do think (personal opinion) that it offers the potential for better finishes/accuracy/concentricity.
One last little nibble:
We know barrels aren't straight right? Range rods, Ouiji boards, and hair of newt is all good. If given a choice about WHERE (that's a hint) to indicate a barrel, ask yourself as you brush your teeth where exactly that spot would be and how would one go about indicating that particular location.
Answer that and you might just get a wee bit smaller next time your at the range.
Good luck.
All the best,
C
Last edited by a moderator:
J
Joel
Guest
I use a Collis Morse Taper Floating Holder http://www1.mscdirect.com/CGI/NNPDF...317401&PMT4TP=*ITPD&PMITEM=67184077&PMCTLG=54 in an Aloris Morse taper holder http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1794809&PMT4NO=83319273 with the Aloris quick change tool post http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=3408845&PMT4NO=83319273
Squaring up the tool holder to the spindle is the most difficult part. To start mount an indicator to the barrel or chuck and indicate the side of the holder so it is parallel to the z axis. Once that’s done reset your indicator so you can rotate your spindle to indicate the x and y of the Aloris tool holder. When you have that indicated in you are ready to chamber.
One caveat. Since we indicated off the outside of the holder we are not sure that the Morse taper is parallel to the outside of the holder. This needs to be checked the first time we use the holder. Even though the floating holder will allow for this I want it as close as possible. Set your indicator so it’s at the front of the holder and swing it. It should read zero. Now set it as far in to the taper as you can reach. Swing it again. Hopefully it is reading zero or close to it. If not you may have to always indicate off the taper or fix the holder.
Squaring up the tool holder to the spindle is the most difficult part. To start mount an indicator to the barrel or chuck and indicate the side of the holder so it is parallel to the z axis. Once that’s done reset your indicator so you can rotate your spindle to indicate the x and y of the Aloris tool holder. When you have that indicated in you are ready to chamber.
One caveat. Since we indicated off the outside of the holder we are not sure that the Morse taper is parallel to the outside of the holder. This needs to be checked the first time we use the holder. Even though the floating holder will allow for this I want it as close as possible. Set your indicator so it’s at the front of the holder and swing it. It should read zero. Now set it as far in to the taper as you can reach. Swing it again. Hopefully it is reading zero or close to it. If not you may have to always indicate off the taper or fix the holder.
JerrySharrett
Senile Member
One caution about many commercial floating holders. Many commercial floating holders are designed to float straight sided reamers and twist drills. These tools, especially straight sided reamers do not have a tendency to cut sideways, They would require a lot of side pressure to get them to go off axis.
Chambering reamers are mostly angular surfaces and this gives them reason to cut on the sides of the flutes. This is why chambering reamers, mainly for bottle-neck cases can easily cut off axis and when it does this makes for an oversize chamber.
Some small amount of oversizing of a chamber, while not great is not too harmful to hunting type chambers that are already SAAMI spec where a size difference of 0.010" from maximum chamber to minimum cartridge is common. Cut a benchrest chamber oversize by over about 0.015" will cause many problems down the road.
Chambering reamers are mostly angular surfaces and this gives them reason to cut on the sides of the flutes. This is why chambering reamers, mainly for bottle-neck cases can easily cut off axis and when it does this makes for an oversize chamber.
Some small amount of oversizing of a chamber, while not great is not too harmful to hunting type chambers that are already SAAMI spec where a size difference of 0.010" from maximum chamber to minimum cartridge is common. Cut a benchrest chamber oversize by over about 0.015" will cause many problems down the road.
J
Joel
Guest
Jerry
Excellent point. That’s why I recommend the Collis Morse Taper Floating Holder. It is designed as a floating tap holder. It handles both angular and radial offsets. When I purchased them twenty years ago I could have quoted you the specs. I have long since forgotten them.
Last edited by a moderator: