threading insert help

[RonnieMaxwell]

need some suggestions on thread insert grade/selection as i keep chipping the insert while trying to true up receiver. have a Howa 1550 that i set up in jig to true face and threads. after picking up thread and after about 2 passes it keeps chiping the tip off and havent had this happen before on Rem's. i use Carmex and for this project picked up a 1.5 pitch in the PC25 grade as i figured it would be best grade.

any suggestions on type and grade for truing a Savage as they ahve interrupted threads and concerned about insert that can take that a well.

any suggestion would be helpful.

Ron

 

[Rustystud]

I would recomend you switch to HSS. Much more durable at slow speeds with SS or CM in a manual machine.
Nat Lambeth

 

[JohnMill]

Ron ,
You also might try Arthur Warner tool bits, www.arwarnerco.com
He makes HSS inserts and holders. Probably would fit right into your set up.

John

 

[jscandale]

What is the advantage to a HSS insert?

Thanks
JS

 

[therifler]

HSS is the way to go providing you can grind them properly in this application it will not fracture or break down as carbide .Nate is right on this one .i know it is alot easier to slap in an insert but it could get rather expensive . Slower process with HSS, but you should only need to set up once .
Slow spindle speed hope this helps . T.R.

 

[jscandale]

I have been using carbide inserts at low speed with black oil and hardly ever chip one. I would just assume grind a tool bit out of HSS rather than spend the money on inserts.

JS

 

[JohnMill]

HSS inserts- more edges per insert- someone else sharpens it for you ( for me)- easily and quickly replaceable-better finish at low speed.
I was taught the real advantage of cemented carbide inserts was the phenominal speeds and feeds you could use. Far beyond the capabiliyies of most home machinists
I never was too interested in sharpening HSS tool bits and, consequently, was never very good at it. I know ,a character flaw BFD. I've used the diamond toolholder with good results too but never got the threading bit right.
Check out Vipers presentation of the Warner tooling. http://www.youtube.com/watch?v=LKGkkGFsF50&feature=mfu_in_order&list=UL
Bob Pastor does a good job there with the description and advantages. He is a nice guy and always passing out tidbits of knowledge.
These are all just suggestions for dealing with lathe work. Hope I didn't get too far off thread
John

 

[jscandale]

Goo video. I might have to try it but pretty price. I have gotten some very good carrier holders and inserts from www.shars.com. You will see that the prices are very low.

JS

 

[Robert]

I would recomend you switch to HSS. Much more durable at slow speeds with SS or CM in a manual machine.
Nat Lambeth

Quite correct, but is not simply the receiver in question case herdened making it not workeable?

R.G.C

 

[kendog]

For most rifle smithing tasks, HSS works much better. At least in my shop.
I order carbide pre-chipped and already damaged to save some time.

 

[JohnMill]

Good planning Ken. Time IS money after all.


John

 

[kendog]

I think I'm alergic to carbide. Just look at them crosseyed, and they break.

Seriously, to the original poster, HSS just seems to work better at the speeds and feeds I use. I have both carbide insert, and HSS threading bits. One HSS threading bit has lasted, with minor stoning, for 15 years. Not so with the carbide.
For the inside threads on a receiver, the Warner high speed bits look interesting.

 

[JohnMill]

I just did a search for the Howa 1550 and found a long thread at THR. I did not see any mention of it being case hardened so could Robert or anyone give us more info on that?
I did not know that Savages were an interrupted thread or perhaps I do not understand what that is. Ron could you describe that a little bit for me, please?

Thanks
John

 

[kendog]

Several years ago, while doing a box magazine conversion for a friend (M14 mag in a Howa 1500), I chased the metric threads in the receiver with a 1-1/16-16 tap to fit a Remington thread pattern barrel. The material was tough, but cut freely, and the tap is still good. I dont know if the 1550 is the same action, but it appears to be i the same family, like Rem 700, 722, etc.

 

[DickE]

Howa and Ruger actions are investment castings. Extremely hard stuff. I've worked with other projects, made with investment castings using carbide inserts, and have gotten sparks and very short tool life. High speed steel or cobolt is near useless. Facing the receiver is about all you can do. Many gunsmiths won't work on them for such reasons.