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bartfrncs
Guest
MY lathe is not large enough to chamber through the head stock. How do you chamber with your steady rest?
JerrySharrett
Senile Member
A suggested method.
Steadyrest chambering
Any of you guys who chamber regularly using a steadyrest jump in here if you have a better method for any and all steps.
First-things you must have;
-A lathe with enough center distance to swing the barrel with one end in the headstock chuck, the other end of the barrel in the steadyrest and about 10” left over between the tailstock spindle and the right end of the barrel. You will be chucking on less than 1” of the barrel end and the steadyrest will be running on the last ¾” or thereabouts. So, if you are chambering a 30” barrel for like a 600/1000 yard gun, the face of the chuck jaws to the right end of the steadyrest points will need to be about 29.5”. Add to that the required 10” of working room and your lathe must have almost 42” from the chuck jaw faces to the tailstock spindle nose. To chamber a 22” barrel you would need about 34”. You can make some compromises here but not much, say 30” minimum for a 22” barrel.
-A steadyrest capable of rigidly holding one end of the barrel.
-A piloted centering tool to generate 60 degree centers.
-A rigid and adjustable lathe chuck for the headstock. This can either be a 4-jaw chuck or a 3 or 6 jaw adjustable chuck like a Tru-adjust style.
For starters I’m assuming you already know what finished length you want the barrel to be.
At this point, either saw the barrel to length leaving about 1/2” on each end or cut the barrel off with a parting tool (cutoff tool) by chucking on one end, running the other end in the steadyrest. The lathe carriage must be set between the steadyrest and the tailstock for this and all following operations that require using the lathes carriage/cross slide. For the chamber reaming operation the carriage/cross slide can be parked between the lathe chuck and the steadyrest.
Getting started, face both ends to just clean up if you sawed the barrel off. Then with the barrel muzzle in the headstock chuck, use the piloted centering tool to make a center in the other end. Swap the barrel around and center the other end. On these centers, just barely make the 60 degree bevel; say about 0.03”-0.045” of 60 degree flat. You will shortly be machining these off and remember you only left the barrel about ½” long on either end so don’t put centers in that are the size of a cows butt!!
At this point, you can set the barrel between centers and drive it with a lathe dog, or driving screw, if you need to take the barrel out regurally to check thread fit, cone fit, or headspace as in the case where you would have a glued-in action. Or, you can continue to use the chuck jaws to drive the barrel if you have tools to check thread fit, headspace, etc. while the barrel is still in the lathe.
Now, the barrel being set up with the muzzle end toward the tailstock, run a 60 degree center in the center you recently made and turn the muzzle end about 7/16” just to clean up the outside diameter (OD).
Turn the barrel around and with the 60 degree center inserted in the chamber end, torn the barrel tenon to about 0.010” over finish diameter and to length lacking about 0.015”. At these operations the steadyrest will be backed away from the barrel OD.
Next, with the steadyrest supporting the barrel on the roughed tenon, carefully recut the 60 degree center just to clean up. At this point use a dial indicator and indicate the chamber throat area. If the lands in the throat are running within 0.001”-0.002” you are good to go. Otherwise you are in the almost unsolvable problem with steadyrest chambering.
If this runout is excessive, say over 0.004” or so, you will have to make an adjustable bushing that has jackscrews, like a headstock spider. This adjustable bushing must have a bore no less than about 1/16” diameter over the maximum diameter of the biggest barrel you plan on chambering. This bushing will hold the barrel where the steadyrest will set and allow reindicating the chamber neck.
Where, above, you were running the steadyrest on the roughed tenon, this bushing must be set to the left of the tenon enough to allow remachining the roughed tenon. If you are using this adjustable bushing method, reindicate the chamber throat by adjusting the jackscrews. Then take a slight cleanup cut on the tenon OD. Continuing, reset the steadyrest on the recut tenon and reindicate the chamber throat. If you did everything correctly, now, with the steadyrest dunning on the recut tenon, the chamber throat now should indicate within 0.001” or less.
At this point, you can either;
1- rough drill the chamber body, taking care to leave material in the body bore and shoulder areas.
2- Or, rough the chamber with a roughing reamer.
3- Or, simply cut the chamber using the finish reamer.
I’m assuming here, you know how to measure headspace. Finish the barrel’s chamber end either as a cone, or counterbore or however your barrel needs to be. Finish the tenon diameter to size and length. Note; recheck headspace after this operation. You may have to run the finish reamer a little deeper based on how much you took off the tenon shoulder in the finish operation.
Next, thread the tenon. You will be now running the chamber end in a 60 degree center and the steadyrest backed off out of the way. Many gunsmiths feel they get a better thread finish using a dead center instead of a live center for the threading.
Turn the barrel around and finish the barrel to length and cut the crown.
I have left out a few steps that will become obvious as you go along since I am not trying to teach you how to run a lathe, just do barrel chambering. (steps like, using a roller steadyrest or lubing the area where the steadyrest runs in case you do not have rollers).
I’m going to post this now. I may have left out steps and others may want to make corrections or changes or simply just add suggestions.
I wrote this in a hurry and on only one cup of coffee this morning so BEWARE!!
Steadyrest chambering
Any of you guys who chamber regularly using a steadyrest jump in here if you have a better method for any and all steps.
First-things you must have;
-A lathe with enough center distance to swing the barrel with one end in the headstock chuck, the other end of the barrel in the steadyrest and about 10” left over between the tailstock spindle and the right end of the barrel. You will be chucking on less than 1” of the barrel end and the steadyrest will be running on the last ¾” or thereabouts. So, if you are chambering a 30” barrel for like a 600/1000 yard gun, the face of the chuck jaws to the right end of the steadyrest points will need to be about 29.5”. Add to that the required 10” of working room and your lathe must have almost 42” from the chuck jaw faces to the tailstock spindle nose. To chamber a 22” barrel you would need about 34”. You can make some compromises here but not much, say 30” minimum for a 22” barrel.
-A steadyrest capable of rigidly holding one end of the barrel.
-A piloted centering tool to generate 60 degree centers.
-A rigid and adjustable lathe chuck for the headstock. This can either be a 4-jaw chuck or a 3 or 6 jaw adjustable chuck like a Tru-adjust style.
For starters I’m assuming you already know what finished length you want the barrel to be.
At this point, either saw the barrel to length leaving about 1/2” on each end or cut the barrel off with a parting tool (cutoff tool) by chucking on one end, running the other end in the steadyrest. The lathe carriage must be set between the steadyrest and the tailstock for this and all following operations that require using the lathes carriage/cross slide. For the chamber reaming operation the carriage/cross slide can be parked between the lathe chuck and the steadyrest.
Getting started, face both ends to just clean up if you sawed the barrel off. Then with the barrel muzzle in the headstock chuck, use the piloted centering tool to make a center in the other end. Swap the barrel around and center the other end. On these centers, just barely make the 60 degree bevel; say about 0.03”-0.045” of 60 degree flat. You will shortly be machining these off and remember you only left the barrel about ½” long on either end so don’t put centers in that are the size of a cows butt!!
At this point, you can set the barrel between centers and drive it with a lathe dog, or driving screw, if you need to take the barrel out regurally to check thread fit, cone fit, or headspace as in the case where you would have a glued-in action. Or, you can continue to use the chuck jaws to drive the barrel if you have tools to check thread fit, headspace, etc. while the barrel is still in the lathe.
Now, the barrel being set up with the muzzle end toward the tailstock, run a 60 degree center in the center you recently made and turn the muzzle end about 7/16” just to clean up the outside diameter (OD).
Turn the barrel around and with the 60 degree center inserted in the chamber end, torn the barrel tenon to about 0.010” over finish diameter and to length lacking about 0.015”. At these operations the steadyrest will be backed away from the barrel OD.
Next, with the steadyrest supporting the barrel on the roughed tenon, carefully recut the 60 degree center just to clean up. At this point use a dial indicator and indicate the chamber throat area. If the lands in the throat are running within 0.001”-0.002” you are good to go. Otherwise you are in the almost unsolvable problem with steadyrest chambering.
If this runout is excessive, say over 0.004” or so, you will have to make an adjustable bushing that has jackscrews, like a headstock spider. This adjustable bushing must have a bore no less than about 1/16” diameter over the maximum diameter of the biggest barrel you plan on chambering. This bushing will hold the barrel where the steadyrest will set and allow reindicating the chamber neck.
Where, above, you were running the steadyrest on the roughed tenon, this bushing must be set to the left of the tenon enough to allow remachining the roughed tenon. If you are using this adjustable bushing method, reindicate the chamber throat by adjusting the jackscrews. Then take a slight cleanup cut on the tenon OD. Continuing, reset the steadyrest on the recut tenon and reindicate the chamber throat. If you did everything correctly, now, with the steadyrest dunning on the recut tenon, the chamber throat now should indicate within 0.001” or less.
At this point, you can either;
1- rough drill the chamber body, taking care to leave material in the body bore and shoulder areas.
2- Or, rough the chamber with a roughing reamer.
3- Or, simply cut the chamber using the finish reamer.
I’m assuming here, you know how to measure headspace. Finish the barrel’s chamber end either as a cone, or counterbore or however your barrel needs to be. Finish the tenon diameter to size and length. Note; recheck headspace after this operation. You may have to run the finish reamer a little deeper based on how much you took off the tenon shoulder in the finish operation.
Next, thread the tenon. You will be now running the chamber end in a 60 degree center and the steadyrest backed off out of the way. Many gunsmiths feel they get a better thread finish using a dead center instead of a live center for the threading.
Turn the barrel around and finish the barrel to length and cut the crown.
I have left out a few steps that will become obvious as you go along since I am not trying to teach you how to run a lathe, just do barrel chambering. (steps like, using a roller steadyrest or lubing the area where the steadyrest runs in case you do not have rollers).
I’m going to post this now. I may have left out steps and others may want to make corrections or changes or simply just add suggestions.
I wrote this in a hurry and on only one cup of coffee this morning so BEWARE!!
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benconrad
Guest
A question, which way is the fastest and which way is the best for smiths who do both ways?
I've done it both ways and if you don't use a sleeve to align the throat in the steady and use the traditional steady method it is faster than indicating both ends in the headstock. I have used a bell chuck (looks like a sleeve with alignment bolts on both ends, an action truing fixture is a bell chuck) indicating the throat with one set of setscrews on one end to dial it in and snug the setscrews on the other end to stabilize the sleeve once dialed in. Then double checking the bore alignment after all of this. When using a sleeve/bell chuck to dial in the throat it is probably a wash on setup time between headstock and steady. The best way? I'm sure that will continue to be debated for a while.
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benconrad
Guest
Questions again
Is the sleeve you use and the bell chuck you use the same design, just smaller for the sleeve?
How much in quality/accuracy, on average, would you guess you are giving up with the steadyrest by not using a sleeve======loaded question?
If you were to use a sleeve rather than a bell chuck the sleeve would be shorter in length if that is what you mean. A bell chuck would need only be long enough for the setscrews to clear the steady's fingers. I have different size bell chucks for different purposes (action truing, barrel alignment, size die reaming). They are all homemade.
How much do you give up not indicating the throat by putting a barrel in the steady? I can't answer that, I don't know. Depends on bore straightness for one I would think. Another depends on your reaming methods and how well you believe your reamer/reamers follow the bore. I believe Kelby's are done in the steady and a roughing then finishing reamer is used. I think they also CNC the tenons on some before reaming in the steady.
I have a new (new to me but old) lathe and am chambering through the headstock now. A machinist friend thinks there are some advantages to using the steady. Has to do with lathe leveling and alignment. He says the steady is more forgiving to lathe misalignment.
JerrySharrett
Senile Member
If you look at the pictures Roy Dunlap used in his Rifle Magazine articles, you can immediately see where some of the support AND confusion that came from chambering in a steadyrest.
In chambering through the headstock, the tailstock must be in perfect alignment with the headstock if you are not using a floating reamer device. Notice I said device not holder. Any unleveling or twist on a lathe, especially small lathes, will result in the AXIS of the headstock not being in perfect alignment with the tailstock AXIS.
In Roy's pictures, he uses a dead center in the tailstock to push the reamer. But remember, in using the tailstock, the barrel was set up with a center in the tailstock. That is how the steadyrest is adjusted, with the barrel in the tailstock center. So if the lathe is in a twist or is not level, no problem because the tailstock is in proper relation to the chamber to be reamed. Proper relation to where the reamer started, not necessarily where the reamer ends.
Then, when chambering through the headstock came along, partly because some gunsmiths got bigger lathes, their chambers did not necessarily come out to the right diameter.
Then came floating reamer holders. Some good, some bad, because these simple floating holders do not always float as they should. There are floating holders that work well but they are in the $400-$900 price range.
Now, many headstock chamberers (new word??) use a device I call a floating pusher. You can see one type on Mike Bryant's web site. Billy Stevens swears by one as do many other top benchrest gunsmiths.