lathe tool

J

johan teughels

Member
i can not find a good insert ore HSS grind form to cut the 120 drg bolt taper in the barrel . i always need to finish it with sandpaper to get it smooth
what do you guys use to do it pic from HSS tool probably can help a lot
 
johan teughels said:
i can not find a good insert ore HSS grind form to cut the 120 drg bolt taper in the barrel . i always need to finish it with sandpaper to get it smooth
what do you guys use to do it pic from HSS tool probably can help a lot
Click to expand...

120 degree?? Are you talking about the breech end where the bolt nose fits?

Hopefully you are not trying to cut this surface with a forming tool. This surface is to be machined with the compound set to the desired degree and cut with a single point tool.

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To the OP,

I'll share what I learned after buying different tools and inserts to achieve what I think is an improvement from when I started. I finally settled on the Arthur Warner 35 degree tool, but instead of using the HSS insert that came with the tool, after trying different ones, I settled on these inserts, VCGT 110302-AL K10 for Aluminum (VCGT 220.5). That is the description on eBay.

Here is the Arthur Warner Tool and a sample of the recessed target crown I do on AR barrels. Unpolished, done on a set thru 6J. Spinning the spindle fast and making shallow cuts. I use the same set cutting bolt nose recess. Remember this is just a job by a rookie, it may not meet the standard for most of the people here, but it is about all I can do at the present with my skills.
 

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Hal said:
Nez

Is that # for the 3/8s tool holder ?

Very nice looking finish ad crown.

Hal
Click to expand...

Hal,

Thank you for the kind words.

Yes, it is the 3/8. Even it is small enough I still ground extended the bottom relief angle for little insurance to ensure it does not touch.

Nez
 
JerrySharrett said:
120 degree?? Are you talking about the breech end where the bolt nose fits?

Hopefully you are not trying to cut this surface with a forming tool. This surface is to be machined with the compound set to the desired degree and cut with a single point tool.

.
Click to expand...

yes and i will cut it with a sigle point tool (that is wat i do normaly )
 
NezRongero said:
To the OP,

I'll share what I learned after buying different tools and inserts to achieve what I think is an improvement from when I started. I finally settled on the Arthur Warner 35 degree tool, but instead of using the HSS insert that came with the tool, after trying different ones, I settled on these inserts, VCGT 110302-AL K10 for Aluminum (VCGT 220.5). That is the description on eBay.

Here is the Arthur Warner Tool and a sample of the recessed target crown I do on AR barrels. Unpolished, done on a set thru 6J. Spinning the spindle fast and making shallow cuts. I use the same set cutting bolt nose recess. Remember this is just a job by a rookie, it may not meet the standard for most of the people here, but it is about all I can do at the present with my skills.
Click to expand...

looks great i got the same tool for the crown but it is t he other side of the barrel i got trubble getting a good finish so i am looking for a tool to cut that side
 
Process suggestion. These bolt nose angles should be machined from the inside out, bore to OD. The single point tool should have at least 11 degree bottom rake instead of he traditional 7 degree rake you normally have on a turning tool.

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JerrySharrett said:
120 degree?? Are you talking about the breech end where the bolt nose fits?

Hopefully you are not trying to cut this surface with a forming tool. This surface is to be machined with the compound set to the desired degree and cut with a single point tool.

.
Click to expand...

Why not a form tool? Nothing touches this surface anyway so the finish shouldn't matter except for appearences and no one can see it once it's screwed on the receiver. I hadn't thought of using a form tool but it seems like a faster, easier less complicated way to do it to me.
Where am I wrong?
Dave
 
burtona said:
Why not a form tool? Nothing touches this surface anyway so the finish shouldn't matter except for appearences and no one can see it once it's screwed on the receiver. I hadn't thought of using a form tool but it seems like a faster, easier less complicated way to do it to me.
Where am I wrong?
Dave
Click to expand...

Wrong? Possibaly not. But do you have a lathe large enough to stabilize a tool with that much surface contact area? Try it.


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burtona said:
Why not a form tool? Nothing touches this surface anyway so the finish shouldn't matter except for appearences and no one can see it once it's screwed on the receiver. I hadn't thought of using a form tool but it seems like a faster, easier less complicated way to do it to me.
Where am I wrong?
Dave
Click to expand...
I've never used a form tool for cutting a coned breech. Most of the ones I've seen photos of use a piloted cutter. That would necessitate you cutting the cone before you do the chamber. I bore out most of the chamber with a 1/4" carbide boring bar with triangle insert before chambering. The start of the chamber is bored to the shoulder diameter to start the reamer in the bored hole. After the chamber is reamed to depth or slightly less then I cut the coned breech with the same boring bar. If the finish isn't good, then I turn the insert to another point or replace the insert. A quick finish with 320 grit sand paper removes any minor tooling marks. If the bored start of the chamber doesn't clean completely up when the chamber is reamed, then it is cut off when the cone is cut. If you use a form tool for cutting the cone, then you have to do steps in a different order. Disclaimer: No particular right or wrong way of chambering or to do the barrel work, just different. Only results that matters is what the rifle prints on paper. If it shoots to your expectations, you've done a good job. If not, then you have problems.
 
I'm not a gunsmith or a machinist. That said, I do build RF and CF benchrest and hunting rifles for myself and a few friends. Mostly I'm self taught in the barrel chamber process although I had some formal trade school training in basic machining.
My method of cutting a coned bolt chamber is to cut and thread the tenon with trial fitting the action then using the lathe compound to cut the cone with a final depth by creeping up on the bolt fit. Then I ream the chamber with a finish reamer to a final HS by creeping up on the go gauge. This is a simple (to me) method that is less prone to me screwing something up.
I'm sure that there are less time consuming and more efficient ways cutting the barrel cone but I'm tempted to have a piloted form tool made for this process and try it with the idea of saving some time and making it a little easier.
I've used piloted form tools for crowning 22 and 6mm barrels and for cutting the Rem 700 counter bore and they work well for me.
I use an EMCO Maximat V13 lathe and it seems ridgid enough for the form tools I have.
Dave
 
burtona said:
I'm not a gunsmith or a machinist. That said, I do build RF and CF benchrest and hunting rifles for myself and a few friends. Mostly I'm self taught in the barrel chamber process although I had some formal trade school training in basic machining.
My method of cutting a coned bolt chamber is to cut and thread the tenon with trial fitting the action then using the lathe compound to cut the cone with a final depth by creeping up on the bolt fit. Then I ream the chamber with a finish reamer to a final HS by creeping up on the go gauge. This is a simple (to me) method that is less prone to me screwing something up.
I'm sure that there are less time consuming and more efficient ways cutting the barrel cone but I'm tempted to have a piloted form tool made for this process and try it with the idea of saving some time and making it a little easier.
I've used piloted form tools for crowning 22 and 6mm barrels and for cutting the Rem 700 counter bore and they work well for me.
I use an EMCO Maximat V13 lathe and it seems ridgid enough for the form tools I have.
Dave
Click to expand...

IMO, form tools are ok for removing material. But even piloted tools at best are risky at best for finish work if the contact area is very great. I'd shutter at crowning a Benchrest barrel with a forming tool.

More efficient for what you described, set a long travel dial indicator up to monitor the carriage movement.


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