Hey lads, i think i know the answer to this already but any smiths here, or machinists using metric?? the reason i ask is because im based in ireland and ive learned my thread in metric, everyone here uses imperial for the smithing jobs, i know i can use a converter but the readings im getting vary by as much as .125"(3.175mm)
Gunsmithing imperial/metric
- Thread starter newby
- Start date
Re: imperial/metric
I don't try to convert. If the thread is given in metric that's how it should be cut, drilled and or tapped. If it's given in inches then the same for that. I have never looked and compared taps or dies. But I'm not aware that any of them cross. But then when I was working metric I was issued all the tools needed in metric. If the prints weren't marked as such, it was implied / understood everything else was standard measure.
A couple of handy references are the Technical Reference Handbook by E. P. Rasis and the Pocket Reference by Thomas Glover. I hope this helps.
I don't try to convert. If the thread is given in metric that's how it should be cut, drilled and or tapped. If it's given in inches then the same for that. I have never looked and compared taps or dies. But I'm not aware that any of them cross. But then when I was working metric I was issued all the tools needed in metric. If the prints weren't marked as such, it was implied / understood everything else was standard measure.
A couple of handy references are the Technical Reference Handbook by E. P. Rasis and the Pocket Reference by Thomas Glover. I hope this helps.
Re: imperial/metric
i didnt explain myself properly, i have metric tolling and lathes etc, however i am guessing that the threads on the receiver/barrel on a remington action are not metric, so im wondering if it is even possible to cut an imperial thread on a metric lathe?? also what are the thread demensions on a remmy receiver?? and what imperial system is used? is it BSW or UTS???
i didnt explain myself properly, i have metric tolling and lathes etc, however i am guessing that the threads on the receiver/barrel on a remington action are not metric, so im wondering if it is even possible to cut an imperial thread on a metric lathe?? also what are the thread demensions on a remmy receiver?? and what imperial system is used? is it BSW or UTS???
Re: imperial/metric
btt
btt
Re: imperial/metric
The threads on a Remington are 1 1/16-16TPI and no you can't do it with a lathe that has a metric leadscrew unless you have the change gears that are needed.
The threads on a Remington are 1 1/16-16TPI and no you can't do it with a lathe that has a metric leadscrew unless you have the change gears that are needed.
Re: imperial/metric
the lathes in work have the change gears so ill just have to change the gear train im all new to smithing and imperial so sorry if this seemed like a silly question
the lathes in work have the change gears so ill just have to change the gear train im all new to smithing and imperial so sorry if this seemed like a silly question
Re: imperial/metric
There are no silly questions. Sometimes my answers are a bit brief because of time constraints. If it works the same as doing metric with an imperial leadscrew, once you engage the feed lever you will have to leave it engaged, stop the lathe while at the same time backing the tool out, then reversing the lathe to the starting point. It sounds harder than it really is. Go slow the first time. Now I chamber all barrels with metric threads on my Haas lathe. Change one setting and I'm off to the races.
There are no silly questions. Sometimes my answers are a bit brief because of time constraints. If it works the same as doing metric with an imperial leadscrew, once you engage the feed lever you will have to leave it engaged, stop the lathe while at the same time backing the tool out, then reversing the lathe to the starting point. It sounds harder than it really is. Go slow the first time. Now I chamber all barrels with metric threads on my Haas lathe. Change one setting and I'm off to the races.
Re: imperial/metric
as i understand it the 1 1/16 is the od of the threads of the barrel shank?
as i understand it the 1 1/16 is the od of the threads of the barrel shank?
Re: imperial/metric
1 1/16" is the diameter, 1.0625". I turn all my tenons -.005" under nominal diameter to leave a flat on top of the thread.
JL
There are an assortment of metric threads out there. I've heard of 55 degrees but not 50. The standard is ISO 60 degree so the same tool can be used.
1 1/16" is the diameter, 1.0625". I turn all my tenons -.005" under nominal diameter to leave a flat on top of the thread.
JL
There are an assortment of metric threads out there. I've heard of 55 degrees but not 50. The standard is ISO 60 degree so the same tool can be used.
Re: imperial/metric
i was also just wondering about truing the bolt lugs and lug abutments, if you remove metal from these surfaces are you not creating a gap as you are removing metal?
i was also just wondering about truing the bolt lugs and lug abutments, if you remove metal from these surfaces are you not creating a gap as you are removing metal?
Re: imperial/metric
armourer.308
I know it's difficult to find a riflesmith over there and even harder to spend some time with one but from your last question it seems you don't understand the basics of simple machine work and barrel fitting. I think you may be heading for serious trouble and possible injury if you continue to pursue this without a better understanding of the work involved. There are books out that will teach you the basics but it is nothing more than good sound simple machine work.
Good luck
armourer.308
I know it's difficult to find a riflesmith over there and even harder to spend some time with one but from your last question it seems you don't understand the basics of simple machine work and barrel fitting. I think you may be heading for serious trouble and possible injury if you continue to pursue this without a better understanding of the work involved. There are books out that will teach you the basics but it is nothing more than good sound simple machine work.
Good luck
Re: imperial/metric
I am a complete noob to riflework, but not machining, i undertand the process of thruing the receiver, face it off, chase the threads, and face the lug abutments. I also get truing the bolt, face the bolt, face the rear and fornt of the lugs.
My question was merely if the receiver/action has a set tolerance from the factory and the bolt has one also, then if i face off the rear of the bolt lugs and the the abutments in the receiver, then no matter how small the cut whether it be .005"(.127mm) you are still removing metal from both of these mating surfaces, therefore if i take .005" from both the rear of the bolt lugs and .005" from the lug abutments in the receiver i now have .01" of a gap that wasnt there before, is this small enough not to matter is all?
I am a complete noob to riflework, but not machining, i undertand the process of thruing the receiver, face it off, chase the threads, and face the lug abutments. I also get truing the bolt, face the bolt, face the rear and fornt of the lugs.
My question was merely if the receiver/action has a set tolerance from the factory and the bolt has one also, then if i face off the rear of the bolt lugs and the the abutments in the receiver, then no matter how small the cut whether it be .005"(.127mm) you are still removing metal from both of these mating surfaces, therefore if i take .005" from both the rear of the bolt lugs and .005" from the lug abutments in the receiver i now have .01" of a gap that wasnt there before, is this small enough not to matter is all?
Re: imperial/metric
I understood your question to pertain to an unaltered factory rifle. I wouldn't do much work, as in truing the bolt, on a rifle unless ;1. I could completly true the action and 2. I was going to install a new barrel. At that point what tolerances/dimensions where there to start with don't mean anything as you have a new set of measurements to work with.
I understood your question to pertain to an unaltered factory rifle. I wouldn't do much work, as in truing the bolt, on a rifle unless ;1. I could completly true the action and 2. I was going to install a new barrel. At that point what tolerances/dimensions where there to start with don't mean anything as you have a new set of measurements to work with.
Re: imperial/metric
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: armourer.308</div><div class="ubbcode-body">I am a complete noob to riflework, but not machining, i undertand the process of thruing the receiver, face it off, chase the threads, and face the lug abutments. I also get truing the bolt, face the bolt, face the rear and fornt of the lugs.
My question was merely if the receiver/action has a set tolerance from the factory and the bolt has one also, then if i face off the rear of the bolt lugs and the the abutments in the receiver, then no matter how small the cut whether it be .005"(.127mm) you are still removing metal from both of these mating surfaces, therefore if i take .005" from both the rear of the bolt lugs and .005" from the lug abutments in the receiver i now have .01" of a gap that wasnt there before, is this small enough not to matter is all? </div></div>
If you clean up the lugs/abutments AFTER you fit/headspace the barrel, then yes you will have created a gap and possibly have dangerously over headspaced the rifle. Do your action work first and then fit your barrel to the action.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: armourer.308</div><div class="ubbcode-body">I am a complete noob to riflework, but not machining, i undertand the process of thruing the receiver, face it off, chase the threads, and face the lug abutments. I also get truing the bolt, face the bolt, face the rear and fornt of the lugs.
My question was merely if the receiver/action has a set tolerance from the factory and the bolt has one also, then if i face off the rear of the bolt lugs and the the abutments in the receiver, then no matter how small the cut whether it be .005"(.127mm) you are still removing metal from both of these mating surfaces, therefore if i take .005" from both the rear of the bolt lugs and .005" from the lug abutments in the receiver i now have .01" of a gap that wasnt there before, is this small enough not to matter is all? </div></div>
If you clean up the lugs/abutments AFTER you fit/headspace the barrel, then yes you will have created a gap and possibly have dangerously over headspaced the rifle. Do your action work first and then fit your barrel to the action.
Re: imperial/metric
thanks for clearing that up lads,its a second hand action and im rebarreling
thanks for clearing that up lads,its a second hand action and im rebarreling
Re: imperial/metric
What kind of lathe are you working on ?
Ive a Weiler Condor, it takes less than 30 seconds to swap a change wheel. add a minute for removing the housing, and a few seconds to select the right gear.
you can get the indexable tooling inserts that suit metric or imerial threads, just mark which are which and dont mix em up.
procedure for machining imperial or metric is the same, lock the apron into the lead screw and back the tool out at the end of a cut, put the lathe in reverse, go back far enough, wind the tool back in the required amount, plus the next cut and start the procedure again.
A rifle barreld action is nothing more than a high pressure pump, and when truing and re bareling you are basicaly overhauling the pump.
but get it wrong and things turn nasty
if you have the grasp of the machining, as Dave said, there are plenty of books to learn from.
regards and good luck Pete
What kind of lathe are you working on ?
Ive a Weiler Condor, it takes less than 30 seconds to swap a change wheel. add a minute for removing the housing, and a few seconds to select the right gear.
you can get the indexable tooling inserts that suit metric or imerial threads, just mark which are which and dont mix em up.
procedure for machining imperial or metric is the same, lock the apron into the lead screw and back the tool out at the end of a cut, put the lathe in reverse, go back far enough, wind the tool back in the required amount, plus the next cut and start the procedure again.
A rifle barreld action is nothing more than a high pressure pump, and when truing and re bareling you are basicaly overhauling the pump.
but get it wrong and things turn nasty
if you have the grasp of the machining, as Dave said, there are plenty of books to learn from.
regards and good luck Pete
Re: imperial/metric
colchester triumph 2000, thanks for the info pete
colchester triumph 2000, thanks for the info pete
Re: imperial/metric
no problems with the Colchester., one of the lathes I trained on was a Colchester Triumph.
"the World turns on a Colchester"
regards Pete
no problems with the Colchester., one of the lathes I trained on was a Colchester Triumph.
"the World turns on a Colchester"
regards Pete
Re: imperial/metric
I regularly cut metric threads on a South Bend inch-pattern lathe. I replace the idler gear on the end with two gears pinned together: a 100-tooth and a 127 tooth. That takes care of the basic conversion without buying an expensive complete set of change gears - got the gears quite reasonably from from Boston Gear here in the 'states. the thread setting for 20 threads per inch now becomes 1 mm metric pitch. You still can't cut all the metric pitches, (e.g. 1.5mm) but rarely do you need to. If I need to cut 1.5mm, I swap out the driven 40 tooth gear for a 60 tooth, and I have 1.5mm at the same setting. You can reverse this process to cut most of the inch threads you are likely to need in barrel work.
I find it interesting that so many European rifles use inch system pitch on the barrel threads, though they frequently use 55 degree threads vs the 60 degree that is standard here.
OlManDow
I regularly cut metric threads on a South Bend inch-pattern lathe. I replace the idler gear on the end with two gears pinned together: a 100-tooth and a 127 tooth. That takes care of the basic conversion without buying an expensive complete set of change gears - got the gears quite reasonably from from Boston Gear here in the 'states. the thread setting for 20 threads per inch now becomes 1 mm metric pitch. You still can't cut all the metric pitches, (e.g. 1.5mm) but rarely do you need to. If I need to cut 1.5mm, I swap out the driven 40 tooth gear for a 60 tooth, and I have 1.5mm at the same setting. You can reverse this process to cut most of the inch threads you are likely to need in barrel work.
I find it interesting that so many European rifles use inch system pitch on the barrel threads, though they frequently use 55 degree threads vs the 60 degree that is standard here.
OlManDow
