Old School Mandrel?

[hoz53]

The nice thing about doing it this way is that you can make them different diameters from the front to back. It seems like the front of the receiver raceway tends to run a little larger than the rear more often than not. If a receiver will take a .702 gage pin at the rear and a .703 at the front you can make your mandrel to match. You'll likely encounter another that fits those dimensions soon enough.

-thats what i was thinking--Ill see soon enough how good the lathe will do. thanks

 

[Alex Wheeler]

You'll get out what you put in. Cheap out and turn a poor mandrel and you might as well not bother truing. Truing an action is actually not as easy as most guys make it seem. After you true your action and your chambering the barrel, put that mandrel back inside the action after its hand tight on your tenon in the lathe. Put an indicator on the mandrel just behind the tang, should be about .001" tir. Your checking how square the bore is to the face and how concentric the threads are to the bore. I bet you will start getting real picky if you try this...
I have always taken pride in my trade, a tool purchase is an investment in your trade.

 

[hoz53]

You'll get out what you put in. Cheap out and turn a poor mandrel and you might as well not bother truing. Truing an action is actually not as easy as most guys make it seem. After you true your action and your chambering the barrel, put that mandrel back inside the action after its hand tight on your tenon in the lathe. Put an indicator on the mandrel just behind the tang, should be about .001" tir. Your checking how square the bore is to the face and how concentric the threads are to the bore. I bet you will start getting real picky if you try this...
I have always taken pride in my trade, a tool purchase is an investment in your trade.

I’m glad to hear that and I knew that (pride in your work). Thanks for the idea on the check. I’ll do that. I like to do the best quality work I can in what ever I’m doing as I have pride in my work- sometimes I like to experiment to. It’s sure good to get info here from you guys.

 

[DaveTooley]

View attachment 1193451
Like this or this idea anyway. Thanks Dave

yes

 

[Tucker65]

You'll get out what you put in. Cheap out and turn a poor mandrel and you might as well not bother truing. Truing an action is actually not as easy as most guys make it seem. After you true your action and your chambering the barrel, put that mandrel back inside the action after its hand tight on your tenon in the lathe. Put an indicator on the mandrel just behind the tang, should be about .001" tir. Your checking how square the bore is to the face and how concentric the threads are to the bore. I bet you will start getting real picky if you try this...
I have always taken pride in my trade, a tool purchase is an investment in your trade.

I've been a machinist for years and a hobby gunsmith for only a couple. I have a small cnc mill that I've set up to true the action with. I set the action up vertically and using mandrels that I turned in my lathe I indicate the rod to square it up with the machine. I use a straight mandrel that just barely slides into the action without binding, it's most of the time loose on either end but snug going through both ends. This is the run out I got on the first one I checked. I'm happy with the results both in the lathe and on paper.

 

[Alex Wheeler]

That is what your looking for. Good work. In fact if you start checking customs that way you'll find your results are there with the best customs. I have checked 100's and the guys doing it right become real obvious.
I could not get there truing 700s until I ditched the rod/bushing combo and went to a full length mandrel. I do have a couple that I spent hours turning and polishing to hold .0002-.0003 over 12". My point is that by the time you make a set at that rate, paying for hardened and ground mandrels is cheap.

 

[Shooting in the wind...]

There seems to be a few excellent ideas for making homemade mandrels that can preform just as good as bought one. I have a Delta Rockwell 11x36 metal lathe that i completely rebuild. Im just waiting for the Vfd to arrive to get it powered up. It is a good machine and not worn out. Previous owner bought it new in 1963, and used it for gunsmithing for alot of years. I was told in the earlier days he completed a few small government contracts using the lathe.

 

[hoz53]

That is what your looking for. Good work. In fact if you start checking customs that way you'll find your results are there with the best customs. I have checked 100's and the guys doing it right become real obvious.
I could not get there truing 700s until I ditched the rod/bushing combo and went to a full length mandrel. I do have a couple that I spent hours turning and polishing to hold .0002-.0003 over 12". My point is that by the time you make a set at that rate, paying for hardened and ground mandrels is cheap.

You just use strait mandrals between centers and a dog to turn the action?
It will be interesting to see how close I can turn a 12” bar- I will see pretty quick weather I want to mess with making action mandrals or not. There are some shops around here that I believe have grinders. Ill check into that to. Thanks

 

[Dusty Stevens]

You just use strait mandrals between centers and a dog to turn the action?
It will be interesting to see how close I can turn a 12” bar- I will see pretty quick weather I want to mess with making action mandrals or not. There are some shops around here that I believe have grinders. Ill check into that to. Thanks

A shop with a centerless grinder can grind a bar to .0001 and can do it for $35-50 plus your drill rod you can buy from msc. Youll be lucky to hold .001 over that length but you can sure give it a try!

 

[Shooting in the wind...]

I plan on trying to make a few, i going to start with a few previous one as decribed. Would sure save some money, especially for me just starting out as a gunsmith. If i find they dont meet my expectations then ill find an alternative.

 

[Alex Wheeler]

You just use strait mandrals between centers and a dog to turn the action?
It will be interesting to see how close I can turn a 12” bar- I will see pretty quick weather I want to mess with making action mandrals or not. There are some shops around here that I believe have grinders. Ill check into that to. Thanks

No, you cant cut threads or lug seats that way. The mandrel is just used to indicate off of and action held in a spider. Make small cuts fine tuning your lathe as you go to take out any taper and you should get close. A little taper wont hurt but they have to be straight so check it in v blocks after your done.

 

[hoz53]

No, you cant cut threads or lug seats that way. The mandrel is just used to indicate off of and action held in a spider. Make small cuts fine tuning your lathe as you go to take out any taper and you should get close. A little taper wont hurt but they have to be straight so check it in v blocks after your done.

Ok thanks

 

[INTJ]

There are also these:

https://www.brownells.com/gunsmith-...ng-tools/receiver-facing-mandrel-prod415.aspx