What is your method of threading on a manual lathe, do you cut a relief for the end of the thread to run out into, do you reverse your lathe at the end of cut or disingage and reingage the feed, for the next cut, also do you set the compound angle attachment at 60 degrees and feed in with that or just use the crossfeed dial.
Gunsmithing threading, barrels
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Re: threading, barrels
You set compound @ 29 to 29.5 degrees and feed with compound only, not crossfeed. Well at least that is the way I do it and many others also for correct thread cutting.
You set compound @ 29 to 29.5 degrees and feed with compound only, not crossfeed. Well at least that is the way I do it and many others also for correct thread cutting.
Re: threading, barrels
That's the way I was taught . . . and by the best, my Dad.
That's the way I was taught . . . and by the best, my Dad.
Re: threading, barrels
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">You set compound @ 29 to 29.5 degrees and feed with compound only, not crossfeed. Well at least that is the way I do it and many others also for correct thread cutting. </div></div>
Yes using the compound is the correct way, but have done threads with the crossfeed only and detected no difference. have even threaded without setting the compound and just dial in with the crossfeed.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">You set compound @ 29 to 29.5 degrees and feed with compound only, not crossfeed. Well at least that is the way I do it and many others also for correct thread cutting. </div></div>
Yes using the compound is the correct way, but have done threads with the crossfeed only and detected no difference. have even threaded without setting the compound and just dial in with the crossfeed.
Re: threading, barrels
You want to cut with the compound so you are only cutting with the leading edge of the bit. You will want to clean it up afterwards with the crossfeed though (cutting with both edges).
If you set your compound at 60 degrees, you are going to have one funky looking thread, I set it at 29 degrees the way it has been done forever.
You want to cut with the compound so you are only cutting with the leading edge of the bit. You will want to clean it up afterwards with the crossfeed though (cutting with both edges).
If you set your compound at 60 degrees, you are going to have one funky looking thread, I set it at 29 degrees the way it has been done forever.
Re: threading, barrels
If you use only the crossfeed you are plunging your bit 90 degree into your workpiece and expecting both sides to cut! I know why this is not correct but don't know exactly how to describe it in simple 'lathe man' terms!!! You really need to read a good machinist guide on thread cutting which will describe in detail how/why using the compound to advance cutter is the ONLY correct way to do it. For one thing your thread depth will more than likely be shallow? as you will reducing your major diameter before proper depth is reached.
I suck at trying to type what I am thinking. Just read a machinist guide or.....keep doing it your way if you feel you are doing it right and achieve what you want done!
If you use only the crossfeed you are plunging your bit 90 degree into your workpiece and expecting both sides to cut! I know why this is not correct but don't know exactly how to describe it in simple 'lathe man' terms!!! You really need to read a good machinist guide on thread cutting which will describe in detail how/why using the compound to advance cutter is the ONLY correct way to do it. For one thing your thread depth will more than likely be shallow? as you will reducing your major diameter before proper depth is reached.
I suck at trying to type what I am thinking. Just read a machinist guide or.....keep doing it your way if you feel you are doing it right and achieve what you want done!
Re: threading, barrels
yup,feed in with compund set at 29.5.... 2-.010" cuts..then 2-.005" cuts... then carefully .002" at a time til you get there....straight in on carriage for last .002" for clean-up.Set-up dial indicator to retract tool as nearing shoulder.... under cutting makes a weaker joint.
That`s the way the USN taught me....
bill larson
MR-2 aboard the USS Ozark MCS-2 `65-`69
yup,feed in with compund set at 29.5.... 2-.010" cuts..then 2-.005" cuts... then carefully .002" at a time til you get there....straight in on carriage for last .002" for clean-up.Set-up dial indicator to retract tool as nearing shoulder.... under cutting makes a weaker joint.
That`s the way the USN taught me....
bill larson
MR-2 aboard the USS Ozark MCS-2 `65-`69
Re: threading, barrels
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wtopace</div><div class="ubbcode-body">You want to cut with the compound so you are only cutting with the leading edge of the bit. You will want to clean it up afterwards with the crossfeed though (cutting with both edges).
If you set your compound at 60 degrees, you are going to have one funky looking thread, I set it at 29 degrees the way it has been done forever. </div></div>
some lathe compounds are based off of the spindle centerline and others are based off of the cross feed. 60* from the spindle axis is the same as 30* from perpendicular to the spindle axis.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wtopace</div><div class="ubbcode-body">You want to cut with the compound so you are only cutting with the leading edge of the bit. You will want to clean it up afterwards with the crossfeed though (cutting with both edges).
If you set your compound at 60 degrees, you are going to have one funky looking thread, I set it at 29 degrees the way it has been done forever. </div></div>
some lathe compounds are based off of the spindle centerline and others are based off of the cross feed. 60* from the spindle axis is the same as 30* from perpendicular to the spindle axis.
Re: threading, barrels
Lathes with a lot of wear will eventually kick you in the nuts if you feed with the cross. Using the compound keeps the lead screw loaded as well as taking less cut. There is a reason they don't teach the easy way vs the right way. If you were making a bolt for a garden gate, no biggie if you roach it......a $400 blank.....do it right and thank me later.
Lathes with a lot of wear will eventually kick you in the nuts if you feed with the cross. Using the compound keeps the lead screw loaded as well as taking less cut. There is a reason they don't teach the easy way vs the right way. If you were making a bolt for a garden gate, no biggie if you roach it......a $400 blank.....do it right and thank me later.
Re: threading, barrels
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">If you use only the crossfeed you are plunging your bit 90 degree into your workpiece and expecting both sides to cut! I know why this is not correct but don't know exactly how to describe it in simple 'lathe man' terms!!! You really need to read a good machinist guide on thread cutting which will describe in detail how/why using the compound to advance cutter is the ONLY correct way to do it. For one thing your thread depth will more than likely be shallow? as you will reducing your major diameter before proper depth is reached.
I suck at trying to type what I am thinking. Just read a machinist guide or.....keep doing it your way if you feel you are doing it right and achieve what you want done! </div></div>
have measured threads with the three wire method, also used a guage, doesnt romove any extra off the diameter. it works without using the compound, you would think it would cut light on one side of the thread, but the last cut still removes the same amount of material from both sides.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">If you use only the crossfeed you are plunging your bit 90 degree into your workpiece and expecting both sides to cut! I know why this is not correct but don't know exactly how to describe it in simple 'lathe man' terms!!! You really need to read a good machinist guide on thread cutting which will describe in detail how/why using the compound to advance cutter is the ONLY correct way to do it. For one thing your thread depth will more than likely be shallow? as you will reducing your major diameter before proper depth is reached.
I suck at trying to type what I am thinking. Just read a machinist guide or.....keep doing it your way if you feel you are doing it right and achieve what you want done! </div></div>
have measured threads with the three wire method, also used a guage, doesnt romove any extra off the diameter. it works without using the compound, you would think it would cut light on one side of the thread, but the last cut still removes the same amount of material from both sides.
Re: threading, barrels
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bill Larson</div><div class="ubbcode-body">yup,feed in with compund set at 29.5.... 2-.010" cuts..then 2-.005" cuts... then carefully .002" at a time til you get there....straight in on carriage for last .002" for clean-up.Set-up dial indicator to retract tool as nearing shoulder.... under cutting makes a weaker joint.
That`s the way the USN taught me....
bill larson
MR-2 aboard the USS Ozark MCS-2 `65-`69 </div></div>
Have done it this way, with a dial indicator, dont think a radius under cut will weaken the barrel enough to effect accuracy, but its probably better not to undercut in case you set the barrel back later, so you dont have a spot without any threads.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bill Larson</div><div class="ubbcode-body">yup,feed in with compund set at 29.5.... 2-.010" cuts..then 2-.005" cuts... then carefully .002" at a time til you get there....straight in on carriage for last .002" for clean-up.Set-up dial indicator to retract tool as nearing shoulder.... under cutting makes a weaker joint.
That`s the way the USN taught me....
bill larson
MR-2 aboard the USS Ozark MCS-2 `65-`69 </div></div>
Have done it this way, with a dial indicator, dont think a radius under cut will weaken the barrel enough to effect accuracy, but its probably better not to undercut in case you set the barrel back later, so you dont have a spot without any threads.
Re: threading, barrels
G92 or death!
G92 or death!
Re: threading, barrels
Just wanted to add all the barrels i have threaded in the past have been done the correct way with the compound and dial indicator ,or cnc lathe. have just used the other methods on farm equipment and such, with the barrel and actions i set them up to run as true as possible usually within .0002 didnt want anyone to think i was doing cob jobs on a rifle.
Just wanted to add all the barrels i have threaded in the past have been done the correct way with the compound and dial indicator ,or cnc lathe. have just used the other methods on farm equipment and such, with the barrel and actions i set them up to run as true as possible usually within .0002 didnt want anyone to think i was doing cob jobs on a rifle.
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