HSS or Carbide for barrel threading

B

Ben H

New member
I'm just getting started and was wondering whether to go with HSS or carbide for barrel threading. My lathe is a Grizzly G0509G and I have upgraded to an Aloris CXA tool post holder. It seems some prefer HSS for a better finish while others prefer carbide. Also, should I go with the largest size shanks my holders will accept? I believe the CXA will accept up to 3/4".

Any and all opinions welcome.

Thanks in advance,
Ben H
 
Either will work satisfactorily.

I started out with a manually ground HSS bit, then last year I tried a BangGood (from Hong Kong) laydown carbide threading tool and it actually cuts better than HSS, plus saves the hassle of grinding the bit, so I'm hooked on carbide now.
 
Ben H said:
I'm just getting started and was wondering whether to go with HSS or carbide for barrel threading. My lathe is a Grizzly G0509G and I have upgraded to an Aloris CXA tool post holder. It seems some prefer HSS for a better finish while others prefer carbide. Also, should I go with the largest size shanks my holders will accept? I believe the CXA will accept up to 3/4".

Any and all opinions welcome.

Thanks in advance,
Ben H
Click to expand...

I'd use high positive holders and carbide. Stay away from negative rake tooling as those machines don't have the rigidity necessary to run negative carbide tooling.

Tool holders, Go with the tallest holders that you can still adjust them to be on center line with the lathe spindle. Determine what the distance from the bottom of the tool holder and the center line of the spindle. I use mostly !" and 3/4" .
they are usually more available and economical compared to the little tool holders, like 1/2-3/8" If tool holders prove to be 3/4 as the best fit, don't be afraid to buy a 1" sq is it's cheap enough,,,,,,,They are machinable and when we just have to have a 3/4 we machine 1/4" off the bottom side.
 
Hss

I use the A R Warner HSS positive rake inserts. They cut very clean and have the ability to cut nice at very low RPM's, this is helpful when working to a shoulder or are a new machinist.
 
This Remington 700 thread tenon was cut with Arthur Warner HSS insert threading tool on a 1963 South Bend Heavy 10 lathe at about 140 RPM
 

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Properly ground HSS or HSSCo will outperform most any of the carbides because carbides need higher surface speeds than HSS does. With these tool room size lathes we use and with operater activated threading engagement we can’t safely thread in the 150-250 SFM range that carbides perform best.

.
 
Rigidity: I often use carbide tooling on my not-so-rigid 12x36's, including some negative tooling. The sky has not fallen. The OP has a 16" lathe that is far more rigid than my machines.

I get a better finish on threads with carbide than with HSS. I've experimented with slowing the RPMs while threading with carbide, just to see what would happen. The sky did not fall. The finish was still better than HSS.

Either carbide or HSS will get the job done.
 
mtngun said:
rigidity: I often use carbide tooling on my not-so-rigid 12x36's, including some negative tooling. The sky has not fallen. The op has a 16" lathe that is far more rigid than my machines.

I get a better finish on threads with carbide than with hss. I've experimented with slowing the rpms while threading with carbide, just to see what would happen. The sky did not fall. The finish was still better than hss.

Either carbide or hss will get the job done.
Click to expand...

amen

rwo
 
A friend

who worked for a Carbide tooling company warned me about using carbide tooling for threading SS. Said one could end up getting a "Chip Ball". Guess what, he was right. I got one and went back to the HSS. The carbide stuff looks nifty but- - - - -. Guess it needs way more speed than I am willing to give it.

Pete
 
Pete Wass said:
who worked for a Carbide tooling company warned me about using carbide tooling for threading SS. Said one could end up getting a "Chip Ball". Guess what, he was right. I got one and went back to the HSS. The carbide stuff looks nifty but- - - - -. Guess it needs way more speed than I am willing to give it.

Pete
Click to expand...

It also needs a heavier cut to remove heat.

Neither is advisable on a less than heavy duty lath.

The slightest flex in the whole setup chips the carbide and results in poor surface finish.

There are some HSS inserts.

The problem is they are only available in limited types.

HSS and cutting lube is more appropriate on smaller laths.
 
Let me be the odd one here. I chamber AR barrels with an old Jet belt drive 1024. To complicate the situation even more, I sort of permanently set the compound for the 223 reamer angle for taper boring, that leaves me threading with the cross slide on a not so rigid baby lathe. I run the spindle at 150 sometimes at 250, threading towards the chuck.

I have the Warner kit and a Thin Bit kit, just out of curiosity I bought these just to see how they perform on 416R barrel.

To my surprise, these laydown uncoated almost razor sharp carbide bits threaded rather nicely. Maybe inferior to yours, for my own consumption good enough. The unpolished, just the way it was cut tenon is 13/16 x 20 x .920 using the new BAT Machine Barrel Extension.
 

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nez,
any comment on the insert being listed as for alum ?
looks like a deal
NezRongero said:
Let me be the odd one here. I chamber AR barrels with an old Jet belt drive 1024. To complicate the situation even more, I sort of permanently set the compound for the 223 reamer angle for taper boring, that leaves me threading with the cross slide on a not so rigid baby lathe. I run the spindle at 150 sometimes at 250, threading towards the chuck.

I have the Warner kit and a Thin Bit kit, just out of curiosity I bought these just to see how they perform on 416R barrel.

To my surprise, these laydown uncoated almost razor sharp carbide bits threaded rather nicely. Maybe inferior to yours, for my own consumption good enough. The unpolished, just the way it was cut tenon is 13/16 x 20 x .920 using the new BAT Machine Barrel Extension.
Click to expand...
 
Most of the naysayers are commenting on results they may have had 20-40 years ago with carbide. All carbide is not the same. It's almost a science to use the right insert, geometry, chip control, coatings and insert material. Like Nez said the inserts have to be sharp ground and of the proper material just for stainless. If you can cut good threads with HSS, you can cut them with carbide, IF you use the proper insert and not something you bought cheap at a swap meet. You have to have a different mindset using carbide on tough materials. You can destroy an insert in a heartbeat if you try to hog with them or try to retract them at the end of the thread like so many think is necessary. Even running a cnc, and ending the thread by retracting the tool can destroy inserts. A flat top sharp pointed generic carbide insert, like a top notch is not going to give you good results on stainless, or any quality heat treated steel.

Such is the case with positive vs negative inserts. There are negative inserts that are molded, negative with positive cutting and precision ground. and a whole library of options in between. They all have their merits and are no different than powder and bullet styles. You have to use the right stuff and you will be fine. If that's more than you bargained for, buy HSS and be happy.
And shoot Military surplus ammo! http://benchrest.com/images/smilies/frown.gif


I say if you think HSS is best for you, and it may very well be, then buy your inserts from a manufacturer like Warner or any of the other companies in that business. Grinding your own is a waste of time, unless you just love getting your fingers burnt and cutting iffy threads. Leave the tool grinding where it belongs, back in the 1950's.

Titanium, aluminum , stainless.....same grade. H13 is a good one for these materials.
 
TRA said:
You can destroy an insert in a heartbeat if you..................... or try to retract them at the end of the thread like so many think is necessary. Even running a cnc, and ending the thread by retracting the tool can destroy inserts.
Click to expand...


I'm so glad you said this :)

I spent a year training and building fixtures and gener'ly tearing my fictive hair out because all the "pros" insisted that only a fade-out thread is any good.

"Stop grooves are for beginners and hacks"

I got to where I was lifting out PERFECTLY on time, and still got wasn't getting perfect results. (And I ain't got no CNC)

I'd be deep into a set of perfect threads and alla'sudden "burn" my tip off.....

Then I read the new 'Centrefire Rifle Accuracy'.......and he 'splained it to me in terms even I could grasp. He showed that lifting out same-same ISN'T GOOD ENOUGH!! It'll eat tips/inserts

I now do a cheater groove, a wimpout groove, a granny groove and bugger-all pride my threads look GOOD, clear to the end :)


lol

al
 
Noted above is a concern on ending the threading pass. When we thread a barrel tenon the cut pass must stop at a shoulder. Some advocate machining a groove to stop the cut in. With the tool retracted If you will move the threading tool to where you want it to stop the cut then, with a dry marker, draw a line on the bedway at the left edge of the carriage wing. Then when making the threading cuts, instead of watching the tool tip, watch the carriage wing as it approaches the mark you made, use that as to where to pull the cutter out.

Practice this method for a few passes, with the tool retracted, to see how this works for you.

Left hand on the cross feed dial, right hand on the half-nut handle.

.

.
 
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