Truing an action questing

A

amosfella

CGN Ultra frequent flyer
Rating - 100%
45   0   0
Location
in the kingdom of the Lord
I was wondering if anyone had used a cylindrical grinder to true an action rather than using a lathe and reamers. The reason that I'm asking is that one can take much smaller cuts with a surface grinder than with a lathe cutter. The Surface grinder can take cuts as small as 0.0002' per side on a cylinder cut and and the same on a facing cut. It also leaves a much smoother surface than the lathe ever can. The lathe with a cutter needs at least 0.003" per side and the same taking a facing cut.

So, has anyone tried it, or will I be the first known to try??
 
What are you trying to true? The outside of the action?

I believe the truing most often done ignores the outside of the action and makes the face of the action, the faces of the lug recesses, the threads, the bolt lugs and the bolt face all as concentric as you can make them - to the bolt throw or bore of the action.
 
Face of the action and the faces of the lug recesses and threads, bolt lugs and bolt faces. One can get an internal grinding set up. As it adds no major amount of pressure to the metal while cutting, I thought it would make things truer with less metal removed, and smoother.
 
Gunsmiths rarely have cylindrical grinders. Most have a lathe.

That about covers that.

If you have the tools and the capability to use them, have at.

Production machining in guns was crap for a long time, and the gains to be had by truing an action were sometimes substantial. Sometimes they weren't, though.
Modern Production machining is to a far closer tolerance, most of the time. Well, except for Marlington.... :)


Cheers
Trev
 
Back in the early seventies Lever Arms bought up a company out of the UK that had gone out of business. All that was left when Alan bought up the inventory were a few hundred K98 large ring actions along with all the bits needed to build up rifles on them. Adjustable triggers, triggerguards with hinged floorplates, walnut stocks and short chambered threaded barrels. You just needed to be careful when you picked out the components that the bolt faces were correct for the chambering you chose.

If memory serves, these receivers and components were for the MIDLAND series of rifles.

Anyway, to make a long story short the actions had all bee trued to their axis inside and out. The threads had been chased and the receivers had been ground, rather than cut. The depths from the receiver face to the inner ring were all identical. I couldn't measure more than about .00025 difference between any of the batch I picked up. The rings and bridges had been ground to accept FN scope bases. The receivers were a mixture of everything 98 large ring Mauser that had been made. By putting them through their refinishing and truing process it allowed the actions to be finished with just a final reaming of the chamber and assembly. I believe the work was done in Yugoslavia to get around the laws being enabled in the UK. So, yes it can be done as long as you have the equipment to do it. Not many smiths have this equipment that I know of. Some of the larger shops in the US might. It just isn't cost effective anymore for smiths to have this type of equipment for the simple reason that new commercial receivers can be purchased with all the work already done cheaper than refinishing a military surplus receiver which are becoming quite valuable.

I am still of the old school and have several 98 actions in varying stages of finish. I like them. Not as easy to work on as a Remington/Savage/Marlin etc but they have that classic retro look that appeals to me.
 
amosfella said:
Face of the action and the faces of the lug recesses and threads, bolt lugs and bolt faces. One can get an internal grinding set up. As it adds no major amount of pressure to the metal while cutting, I thought it would make things truer with less metal removed, and smoother.
Click to expand...

Possibly less metal removed, and I don't know if it would be any truer or any smoother either. I do know it would cost a lot more if you add the cost of the internal grinding machinery plus the increased time to set up and do it. The set up for grinding internal threads sounds very challenging. With the tooling I have now I can true a 700 action for $150.
 
I was looking at buying a id/od grinder to do hydraulic cylinders and shafts. I found a few completely tooled in the $800-$1400 range. I also have a remington that I want to rechamber, and thought an action truing on it would be good. The machining work on this rifle is just atrocious. The bolt cylinder is galled from the drilling, badly... The lugs are only contacting on a very small are on one lug. The face of the bolt is crooked... I'm to the point that I think that this particular rifle was made right at the end of the tooling life.

So, I was thinking that if I bought the machine to do the grinding, I could remove a lot less metal and get it smoother, and possibly eliminate the need to shim or sleeve the bolt. It's not like I'm buying the machine for just one project...
 
amosfella said:
I was looking at buying a id/od grinder to do hydraulic cylinders and shafts. I found a few completely tooled in the $800-$1400 range. I also have a remington that I want to rechamber, and thought an action truing on it would be good. The machining work on this rifle is just atrocious. The bolt cylinder is galled from the drilling, badly... The lugs are only contacting on a very small are on one lug. The face of the bolt is crooked... I'm to the point that I think that this particular rifle was made right at the end of the tooling life.

So, I was thinking that if I bought the machine to do the grinding, I could remove a lot less metal and get it smoother, and possibly eliminate the need to shim or sleeve the bolt. It's not like I'm buying the machine for just one project...
Click to expand...
Spinning your bolt in a drill press and using emery cloth will polish and remove very little metal also on the cylinder part.
Of course a lathe will accomplish all the tasks needed to true an action including squaring the threads. You could also use Manson action truing tools also.
As much as I like surface grinding and it has it's place, but I've never heard of internal surface grinding in gunsmithing.

The outside of the action has nothing to do with actually truing an action except where the barrel meets the shoulder. Everything internally must line up.
What type of precision grinders can you buy for $800-1400 range? What kind of condition are they in?
These are not cheap machines.
 
EHG said:
Spinning your bolt in a drill press and using emery cloth will polish and remove very little metal also on the cylinder part.
Of course a lathe will accomplish all the tasks needed to true an action including squaring the threads. You could also use Manson action truing tools also.
As much as I like surface grinding and it has it's place, but I've never heard of internal surface grinding in gunsmithing.

The outside of the action has nothing to do with actually truing an action except where the barrel meets the shoulder. Everything internally must line up.
What type of precision grinders can you buy for $800-1400 range? What kind of condition are they in?
These are not cheap machines.
Click to expand...

There were a few on auction in the US. volder..... or something like that and a few other brands that I don't remember since my computer crashed. There was a fully tooled norton that looked excellent for $2k in Ontario a short while back...

Also, didn't you read what bearhunter posted above?? ;-)
 
You have to remove enough metal to true a given surface regardless of the method employed. That is to say, if a piece is eccentric by .002, you will have to remove at least .0025 from the high side to true it up. Grinding can produce a nice finish and a true surface but is a bit of an art form in it's own right. As mentioned, most gunsmiths are familiar with lathe work and comfortable with it while grinding is seldom used.
 
While this is true, In excess of the amount you remove to get it true, with a cutter you have to remove enough extra to keep the cutter cutting or it will skip giving an uneven surface.

I was only putting this out there as a topic for conversation. Thought it would be an interesting idea to try. If one has the tools, what's the downside??
 
You must log in or register to reply here.
Back
Top Bottom