Blueprinting Actions

[Leagle]

I am looking to buy a lathe. Most of the one I have looked at, used and new, have spindle bores of from 1.5 - 2.25 inches. This is too small for an action truing sleeve. My budget will not allow for a huge lathe. I use an action truing sleeve that is close to the length of the action I am blueprinting, as I believe that this enables you to better align the action than with the small (lengthwise) truing sleeves sold by Brownells. Any thoughts on how to use my truing sleeves with a small spindle bore?

 

[metalmole]

A picture of your truing sleeve would help, have you ever used your sleeve in a lathe big enough? Any larger bore lathes bigger than "2 are gonna be heavy/large and $$

 

[unioncreek]

You would be better of to chuck the end of the truing sleeve up in the chuck and then the other end into a steady rest. If you sleeves not long enough make a new one, but longer. A lathe with spindle bore greater than 2.25" is going to be pretty spendy.

Bob

 

[Leagle]

I have been using a Mori Seiki 1250 which has a spindle bore easily large enough for what I am doing. I suppose I have been spoiled by access to this type of machinery. The suggestion to use the steady rest is probably the most practical, but I hate using a steady rest. Being a newbie, I always have trouble getting the part indicated in with a steady rest.

 

[Breakit-Fixit]

I use a cat's head fixture supported in my steady rest, with the receiver truing fixture captured inside it, and driven by clutching the other end of the receiver fixture in the 4 jaw chuck.

The cat's head lets me dial in the receiver just as though it were being held in a four jaw.

 

[Leagle]

I am showing my ignorance, but what is a cats head fixture? Where do you get one? What is the advantage of using a cat's head fixture over just using the steady rest with the other end of the fixture in a four jaw chuck?

 

[Stob]

Most truing sleeves are made of thick walled tubing or pipe, of course large enough for an action to fit. Two sets of 4, adjusting screws allow the alignment of the action. The sleeve is typically held in a 4 jaw, or a 3 jaw that can grab the OD of the sleeve. The indicating of the OD on the sleeve is really not needed, the work is inside.

A mandrel is inserted into the action which extends out in front enough to use two dial indicators, and you align both front and back of the action to zero, which sets the action on a true centerline all the length of the action, a theoretical extension of the barrel.

You don't need to hog off metal while truing, all you are doing is just enough to get the faces either i the same alignment, or perpendicular to this centerline. Chasing the threads, locking lugs, action face should only be touched enough to true it, no more. Same with the bolt.

Remember, any metal you take off the action lugs or the bolt lugs, reduce primary extraction. Re-setting the bolt handle is the only fix for this.

All this ca be done with a spindle hole that is smaller than the action, all you need is to grab the truing sleeve.

 

[tripletap3]

This is a photo of the one I made for my lathe. I put three sets of holes in mine for working shorter pistol barrels. I run this in a 4 jaw chuck but the 3 jaw was already on the machine for the photo.
Chuck.

 

[Joe0121]

Maybe I am missing something but every time I have seen an action blue printed in person or on you tube the through hole isn't even used. Some sort of fixture is placed in the jaws indicated and the action place in the fixture and indicated. If ya got 1500 bucks you can buy a true bore alignment system and use a collet to hold the action.
http://www.youtube.com/watch?v=RKvEf8MwnoE

2.25 through bore is more than big enough to get any normal barrel in. There is also some debate whether to thread/chamber barrel between centers or through the head stock. Personally it seems to me through the headstock is better and this is how 90% of the gunsmiths I know do it.

Edit:

Wow still getting used to the way this forum arrange posts. Just realized the Ops question was answered.

 

[Breakit-Fixit]

I am showing my ignorance, but what is a cats head fixture? Where do you get one? What is the advantage of using a cat's head fixture over just using the steady rest with the other end of the fixture in a four jaw chuck?

See post number 8, that's a cat's head being held in that 3 jaw chuck with a barrel held in the Cat's head.

I don't know where you can buy one, I've always just made them out of a chunk of heavy walled steel tubing. They work pretty well for other things besides barrels and actions as well.

You can use them to grip long, odd shaped pieces out away from the chuck, and still dial the work into concentricity with the spindle axis , the cat's head is supported by the steady rest in that application.