Gunsmithing Did you build your own action truing mandrel?

[GasLight]

Wondering how many have built their own mandrel for truing actions? Are you using the PTG bushings, or did you make your own bushings too?

I was thinking of making a rod with taper for the front ring and using a bushing for the rear ring... not sure if that is how the PTG setup is or not...

 

[Mgordon]

Re: Did you build your own action truing mandrel?

You would need to grind it between centers if you really wanted to make one correctly. I have made bushings to get by in a pinch.

Mark

 

[GasLight]

Re: Did you build your own action truing mandrel?

Where did you get the one you use? Would you need it ground instead of turned for the tolerance in the action ring? I would guess a cut mandrel would be good for run-out, and if it was tapered like the range rod, it should work? What do you see as an issue to this method?

Dave

 

[300sniper]

Re: Did you build your own action truing mandrel?

i used some 1/2" drill rod but i don't remember what grade it was. i do remember the tolerances specs on it weren't all that great. i set it up in my 4 jaw and dialed it in to as close to zero runout with my tenth dti and center drilled both ends. i then placed it between centers and had no indicated runout anywhere along it so i considered it good enough.

i made my bushings out of brass.

 

[Glen Seekins]

Re: Did you build your own action truing mandrel?

Remember you wont get it any better than the tooling you use. You need to have a very true mandrel and proper fitting bushings. If your mandrel isnt strait then there is a good chance you will make your truing job worse than factory.

Kiff's kit isnt cheap, but it IS a quality kit.

 

[Jered Joplin]

Re: Did you build your own action truing mandrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: heatseekins</div><div class="ubbcode-body">Remember you wont get it any better than the tooling you use. You need to have a very true mandrel and proper fitting bushings. If your mandrel isnt strait then there is a good chance you will make your truing job worse than factory. </div></div>

Couldn't agree more. If you aren't doing it right you might as well not even touch it.

 

[GasLight]

Re: Did you build your own action truing mandrel?

I appreciate the input, I get ahead of myself, and will wait until I get a mandrel from Kiff before I begin work. It is tough to wait on small tools when you have everything else you need

Thanks again guys

Dave

 

[SamLS]

Re: Did you build your own action truing mandrel?

Yes a good machinist can turn a mandrel which will be more accurate than the kiff tool for a given action. Thats how Greg Tannel and many others started with this technique. Your shaft will have two different size lands on it one near the front ring and at the rear.

 

[GunjunkieM24]

Re: Did you build your own action truing mandrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DemoSam</div><div class="ubbcode-body">Yes a good machinist can turn a mandrel which will be more accurate than the kiff tool for a given action. Thats how Greg Tannel and many others started with this technique. Your shaft will have two different size lands on it one near the front ring and at the rear.</div></div>

Huh?

Kiff builds some the best quality mandrels and precision ground bushings I have ever seen. The mandrel is precsion ground and you fit it with bushings with .0005 increments to get the best fit in the receiver. Hell, David will build you bushings with .0001 increments if you wanted. I dont see any way you could get it more accurate unless you built a specific mandrel for EVERY action you trued since I have never seen two exactly the same. A .500 mandrel and fitted bushings are the only way to go in my opinion...

Just my 02 cents worth.

 

[300sniper]

Re: Did you build your own action truing mandrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GunjunkieM24</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DemoSam</div><div class="ubbcode-body">Yes a good machinist can turn a mandrel which will be more accurate than the kiff tool for a given action. Thats how Greg Tannel and many others started with this technique. Your shaft will have two different size lands on it one near the front ring and at the rear.</div></div>

Huh?

Kiff builds some the best quality mandrels and precision ground bushings I have ever seen. The mandrel is precsion ground and you fit it with bushings with .0005 increments to get the best fit in the receiver. Hell, David will build you bushings with .0001 increments if you wanted. I dont see any way you could get it more accurate unless you built a specific mandrel for EVERY action you trued since I have never seen two exactly the same. A .500 mandrel and fitted bushings are the only way to go in my opinion...

Just my 02 cents worth. </div></div>

i have to agree. and with a one piece, it would be a major pain in the ass if the rear ring area of the raceway was larger than the front.

 

[GasLight]

Re: Did you build your own action truing mandrel?

OK, I have to bring this up again to get some clarification. What we are going for is concentricity, isn't that correct? So if I turn a mandrel down to .500 on my lathe between centers, it is going to be concentric even if the finish isn't a perfect as a ground finish, or am I missing something? if I turn a bushing that is tight in the front or rear ring, then indicate it in the 4-jaw, and drill the center out, then use a chucking reamer to get it to .500" it will be damn close and very concentric.

What is the difference between this and a mandrel and bushings from PTG, other than surface finish. Am I missing something that would be easy to screw up? Is it just tolerances that I am downplaying?

Thanks again

Dave

 

[LRI]

Re: Did you build your own action truing mandrel?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DebosDave</div><div class="ubbcode-body">Wondering how many have built their own mandrel for truing actions? Are you using the PTG bushings, or did you make your own bushings too?

I was thinking of making a rod with taper for the front ring and using a bushing for the rear ring... not sure if that is how the PTG setup is or not...

</div></div>

YEP. Made it all by myself.

Works great!

 

[GasLight]

Re: Did you build your own action truing mandrel?

Chad,

Any pictures of your mandrel? Do you make the bushings too?

Thanks

Dave

 

[LRI]

Re: Did you build your own action truing mandrel?

Yep, just visit the site. Look under the process section. It's all one piece though. I just whipped out a set in .001" increments rather than stack bushings, etc. Less chance of a tolerance stack that way. (Course if David's (PTG) making them this way I'm sure he has that licked as his shop is a bit better equipped than mine and his experience is beyond question.

 

[Glen Seekins]

Re: Did you build your own action truing mandrel?

Consentric and strait are two very diferent things. You can get anything round to spin consentric in one spot. Getting it consentric in 2 spots is night and day different. You want it strait and consentric.

Kiff makes the mandrels for GTan (at least mine says gtan on it) as i belive it was gregs design. Could be off base..

Kiffs part will be more accurate than most lathes gunsmiths use just because of the runout on your spindle bearings. Not many people understand what .0002 realy is.
Grinding to size is a different manufacturing method and easiest way to get very precision parts. Cutters for instance are ground and so is higher end tooling. Not saying you cant make one, but most would be better off to buy.

Gtan makes a very good video for those wanting to see how to true an action. Its a home vid but it gets the job done.