Action Tuning

I have been watching the Video put out by Darrel Holland and was wondering about one thing he does. BTW this is a Rem 700 action I am taking about.
After centering the action in the head stock he faces the recoil lugs and then cleans up the factory threads by running a tap in the threads (Hand powered ) while holding it in line with a live center in the tail stock. So far this makes sense to me.
Next he removes the action from teh headstock and places a threaded mandrel in the headstock and centers it, threads the action on the mandrel and then faces the front of the action.
Now my question, why use the mandrel to face the action? Why not just face the action when he head it in the headstock doing the recoil lug and thread work?
What am I missing?
Thanks
Jeff in ND

My guess is that the fac or a prethreaded barrel was to be instaled, or the tap was the Dave Maison type. Your right it don't make any sense. The mandral is one way to face a action, and only to do the faceing. The idea is the action runs true its entire length. If you indicated a pice in the chuck, the only place it will be true 0 is were the indicator was, ahead and behind will be out of square. I would like to see how he setup the action to cut the lugs, as it mite give a better idea of his plan.

I will try and explain what he did.
He places the action in his precision 6 jaw chuck. He mentions the runout number of this chuck but I don't remember what it was off hand. (I will be using a independent 4 Jaw and dial it in)
From that point he runs the tap in as mentioned.
Next, he determines the location of the recoil lugs by contact with the boring tool and then machines them just enough to make a flat surface.
As mentioned before, this is when he removed the action from the 6 Jaw and places his custom mandral (looks like a barrel stub) in the 6 jaw and screws the action on. Then faces the action.

Why use the mandral? Why not just face the action when it was in the 6 Jaw?

He then goes on the lap the lugs, thread, chamber and headspace the barrel.

I like the video but just can't see why he does the mandrel step. Maybe I will give him a call.

Thanks
Jeff in ND

Hey Jeff
Look real close at what he is doing. I think that the mandrel bottoms off on the same face that that lugs of the bolt hit. The idea here is to get the two perfectly paralel so at lockup everything is centered and square. Least that is my opinion and I am sticking to it!!!!!
Fred T

could be but I don't think so. It looks more like a tappered fit mandrel. I am guessing that due to the effort used to install the action on the mandrel (short wooden dowel through magazine cut out).
I can see where bottoming out on the recoil lugs would make sense but how would it be any better then just facing the action on the first set-up since you just cut the recoil lugs perpendicular to the centerline of the action???

Thanks
Jeff in ND

I have used a similar mandrel I think. I have not seen the video but useing the mandrel ensures the action face is square with the threads. Thus square with the bore if the blank was threaded correctly. I use the mandrel between centers. I don't do the recoil lugs in the lathe.

Hey Jeff
I am not sure why folks use the mandrel either. I wonder if it is not a carry over from when gunsmiths didn't have a four jaw with a large enough hole in the center to hold the action? Or perhaps no four jaw at all. I think the mandrel is a great work around but If I have it in a four jaw I am going to do all I can at one time. I agree with you, if you cut the recoil lug face and the front of the action at the same time then by damn they should be square and paralel. If not I think that there are some serious machine "issues".
Good luck
Fred T

I agree with you Jeff. You are only indicating one point on the action when it is in a chuck. It doesn't matter if you have a perfect spindle and chuck. Thebarrelman

Thanks for the input guys.
I called Darrel Holland and asked him about this. He indicated since the video was make he has made some improvments to his methods.
Now he uses a custom turned mandrel through the action and cuts everything bases on the centerline of the inside of the action. Makes sense to me, maybe I will ty this on the next action I "tune".

Thanks Again
Jeff in ND

The Tap/mandrill has bushings that are tapered from .700 to .705" and are one inch long. The whole deal works great. So far I have had excellent results on Remington 722 and 700 long and short. JUST DON"T USE THEM ON RUGERS. Their actions are seriously hard. I find that I can true a small action in about 30 minutes after I get the barrel off. I use the Mandrill/reamer to true the face, running it between centers. This is easier than setting up in a 6-jaw.

Pretty simple. The mandrel that threads into the action and is held between centers now allows you to true the receiver face in relation to the threads. If you simply trued the face of the receiver while in the headstock, you would be trueing the face in relation to the outside of the receiver. The outside of most receivers is not parellel to the threads. This isn't the best way to true a receiver because it doesn't take into consideration the relationship of locking lugs, receiver threads, bolt way and receiver face. But it is fast and on most varmint and hunting rifles, the results are excellent accuracy.
These threaded mandrals are available through brownells.
If you want a very true receiver, and you don't even need a lathe, check out Dave Mansons tooling. He makes a kit (available through Brownells) that will completelt true up a Remington receiver to just about perfect specs, without a lathe in about 20 minutes!

" " I called Darrel Holland and asked him about this. He indicated since the video was make he has made some improvments to his methods.
Now he uses a custom turned mandrel through the action and cuts everything bases on the centerline of the inside of the action. Makes sense to me, maybe I will ty this on the next action I "tune". ""

This also makes sense to me ... as this is what I started doing AFTER I tried it the
way he stated in the video ..and it didn't work to well for me ... it would work
fine his way IF it was an IDEAL action..
with the threads concentric to the outside
diameter and the center line being straight
and true thru the center..
I found out the hard way ... most actions
aren't ideal .. In fact, the one I tried it
on first was WAAAAAAAAY off in regards to
the threads being in the center of the action..
So I made a mandrel that goes thru the action
and runs between the chuck and the tailstock..
I am ONLY using this to square off the face
of the receiver..
In my feeble mind, I would think that the
face of the receiver would need to be trued and square to the threads .. after all thats
what the barrel screws into .. and its what
decides how well it butts up against the receiver..
Thanks.. IMHO

Randy

ooops ..
Sawwwy all .. I guess I should have read Roy's post before posting my own .. LOL
I agree with him though ..
Seems like the way to do it to me ..
Thanks for the confirmation that I'm thinkin
the correct way on this Roy ..