Gunsmithing Action truing fixture idea

[selfbowhunter]

The LaBounty jig is convenient not precise. You're trying to achieve perpendicularity between the lugs and the bolt body. You can't do it with that fixture.

I was afraid you might say that! Anyone else use a labounty and care to share your experiences? I can see, in theory, where it would work as intended IF it were perfectly made AND the bolt body were perfect. If it was out say .005 when you made the cuts and then the bolt was properly lapped in, how much difference would it make?

 

[moore_man]

Make is easy on yourself and make it long enough to simply clamp on it with your 3 jaw. This one also has a bolt handle relief and is used for both the action and bolt truing work.

 

[moore_man]

I was afraid you might say that! Anyone else use a labounty and care to share your experiences? I can see, in theory, where it would work as intended IF it were perfectly made AND the bolt body were perfect. If it was out say .005 when you made the cuts and then the bolt was properly lapped in, how much difference would it make?

What if you true the action and simply lap the lugs into the newly trued lug surfaces in the action? I've tried several truing methods for both the action and bolt. Full lug contact was always achieved. No strange head scratchers yet.

 

[Boogaloo]

To those of you that have made these fixtures, have you determined a nominal thickness for the inner aluminum sleeve? Also, have you determined a proper clearance between the ID of the outer fixture and the OD of the inner sleeve?

I bored my inner sleeve yesterday, but have yet to turn the OD of the inner sleeve or cut the slots in it. I would like some info on what you guys have found to be proper clearance between the parts that allows adequate gimbal movement to obtain zero runout when all is said and done.

 

[Killswitch Engage]

The point I'm trying to make is some setups are reliable and some aren't. Don't fall into the trap that what works for one process automatically works for another. How reliable/accurate are those two points. First they are not very far apart compared to the length of the bolt. That introduces error that's multiplied over the length of the bolt. Then Remington bolts are made from three pieces. The handle, the body (tubular) and the head which is soldered and pinned to the body. I have never seen the heads attached with any kind of precision. It is never in perfect alignment with the body. Also I have seen bodies that were banana shaped.

To test this turn a 60 degree center on a piece of round stock. You should have this already made already. Put it in a 4 jaw chuck or an adjustable three jaw chuck. Just for giggles indicate that in if done in a 3 jaw and then transferred to a 4 jaw. Put the rear of the bolt on this center and lightly put the center in the tailstock in the firing pin hole. Run an indicator back and forth along the bolt body and see what you get. Then adjust the chuck trying to achieve zero run out front to rear in 4 locations 90 degrees apart on the body. Don't worry about the run out radially. That's not important in this process. Go between the lugs all the way to the nose. Somewhere in the process you'll say this is as good as I can get it. That's when you take a light cut on the rear of the lugs. Then check radially in several places along the body as part of the learning process.

An alternative setup is to screw a stub in the rear of of the bolt. Put it in the lathe clamping on the bolt body, take a clean up cut on the stub(maybe 3/8" long), swap ends holding the stub in the chuck and go through process of aligning the body.

maybe i am off here but why can you simply not screw a 1/2-13 bolt turned true bolt/stub into the back of the bolt body and put your live center in the firing pin hole and indicate the bolt body behind the lugs? this would be under the assumption one has a very well aligned tailstock and precise center. it would seem you could indicate it in many places including both axis if one was so inclined. what am i missing? or maybe this is the same thing youre saying?

next how critical does one think it is if the raceway hasnt been reamed and a more precise bolt body installed that keeps the top lug from coming out of contact with the abutment under sear pressure, to even necesitate these cuts to begin with if the lugs arent galled or damaged?

 

[Aeon1]

Firing pin holes are not always in the center of the bolt. If one is I do what you propose and use a live center in the pin hole, if not I use a different fixture to align the bolt body behind the lugs. For the rear of the bolt I use a threaded stub with a rounded end in the chuck.

 

[Killswitch Engage]

Firing pin holes are not always in the center of the bolt. If one is I do what you propose and use a live center in the pin hole, if not I use a different fixture to align the bolt body behind the lugs. For the rear of the bolt I use a threaded stub with a rounded end in the chuck.

i get that and at the same time i think if the firing pin hole isnt centered and i am not sure that even matters for perpendicular alignment of the lugs to the body. the pin hole could really only cause radial run out, No?

 

[Aeon1]

Banana shaped or not I indicate on the front and rear where the bolt bears on the action. I don't care what the middle of the bolt is doing. Kind of like the choices we have when indicating barrels. We have to pick the points to indicate that we think are important and let the rest go where it may.

 

[Killswitch Engage]

which is all good but these bolt truing fixtures ive seen dont let you indicate on the body at the rear raceway contact point.

 

[Aeon1]

That's why I personally don't use them and do them as described.

 

[Killswitch Engage]

That's why I personally don't use them and do them as described.

just seen your pictures. my work pc doesnt let me see pics sometimes...anyhow thats exactly what i was thinking. good work!

 

[Red_SC]

How do you true the bolt face with that setup?

 

[JJones75]

To those of you that have made these fixtures, have you determined a nominal thickness for the inner aluminum sleeve? Also, have you determined a proper clearance between the ID of the outer fixture and the OD of the inner sleeve?

I bored my inner sleeve yesterday, but have yet to turn the OD of the inner sleeve or cut the slots in it. I would like some info on what you guys have found to be proper clearance between the parts that allows adequate gimbal movement to obtain zero runout when all is said and done.

I bored the inside of my sleeve to 1.355" and the OD is 1.800". The inside my my steel fixture is bored to 1.850"
I have had a couple Remington actions that were snug in the sleeve but this tured out to be from them not being perfectly round. I have never had an action need anything close to the .050" angular alignment and you could probably get away with half of that. I made my last fixture to a backing plate that locks directly to the D1 on the lathe , the whole fixture only sticks 6" off the head stock and is far more rigid than any I have seen mounted in a chuck.

 

[Aeon1]

How do you true the bolt face with that setup?

You don't. You switch to a steady rest behind the lugs and then remove the fixture.

 

[Red_SC]

I made my last fixture to a backing plate that locks directly to the D6 on the lathe , the whole fixture only sticks 6" off the head stock and is far more rigid than any I have seen mounted in a chuck.

Thats a great idea.

 

[Boogaloo]

I bored the inside of my sleeve to 1.355" and the OD is 1.800". The inside my my steel fixture is bored to 1.850"
I have had a couple Remington actions that were snug in the sleeve but this tured out to be from them not being perfectly round. I have never had an action need anything close to the .050" angular alignment and you could probably get away with half of that. I made my last fixture to a backing plate that locks directly to the D6 on the lathe , the whole fixture only sticks 6" off the head stock and is far more rigid than any I have seen mounted in a chuck.

Thank you so much.

Would you mind sharing a pic of the D6 back plate fixture you worked up? I have a keen interest in seeing how that looks. Did you weld a piece of seamless DOM pipe to the backplate, and then bore it to accept the inner sleeve?

 

[hero's machine]

Perhaps we are looking at this too complexly. Vision this.....
collet the outside of the action regardless of bore centerline.
Face the action and lugs, single point the threads and bolt bore.

Did we just build a square action? Sure we oversized the bolt bore......but stay with me.

1/2" stub with a dog to drive from a center, cats head the bolt head to center it.....cut the bolt body for a sleeve where the action rides.
steady rest the freshly cut relief to cut the bolt lugs and center/bush the pin hole......install sleeves.
Now we can put the bolt back in the lathe in centers to cut the bushings.

Point me out the flaws. If it would fly, we save time and end up with a bushed bolt. It takes a whole day longer in the shop. ....but setup time is greatly reduced.

 

[Killswitch Engage]

I'd say because none of that stuff is necessary to produce a rifle that shoots better than the shooter can perform almost everytime. I think alot of the things that get "trued" are unnecessary at best and provide little to no results on target. That's my perspective as a shooter first and wannabe machinist second.

 

[JJones75]

Thank you so much.

Would you mind sharing a pic of the D6 back plate fixture you worked up? I have a keen interest in seeing how that looks. Did you weld a piece of seamless DOM pipe to the backplate, and then bore it to accept the inner sleeve?

I machined a seat into the back plate then turned a piece of solid bar stock to slip fit into it and was bolted in place the ID is bored true once the fixture is installed.
My personal fixture is packed up in storage but I'm working on one for a buddy. I'll get some pics of that as it comes along

 

[300sniper]

Perhaps we are looking at this too complexly. Vision this.....
collet the outside of the action regardless of bore centerline.
Face the action and lugs, single point the threads and bolt bore.

Did we just build a square action? Sure we oversized the bolt bore......but stay with me.

1/2" stub with a dog to drive from a center, cats head the bolt head to center it.....cut the bolt body for a sleeve where the action rides.
steady rest the freshly cut relief to cut the bolt lugs and center/bush the pin hole......install sleeves.
Now we can put the bolt back in the lathe in centers to cut the bushings.

Point me out the flaws. If it would fly, we save time and end up with a bushed bolt. It takes a whole day longer in the shop. ....but setup time is greatly reduced.

You're going to have a hell of a time single point boring the full length of the receiver due to the diameter, depth and a nasty interrupted cut.

 

[hero's machine]

I forgot the interruption .....

 

[djgleeson]

How would you put the sleeve on the bolt though? The lugs are on one end and the bolt handle is on the other.

 

[JJones75]

How would you put the sleeve on the bolt though? The lugs are on one end and the bolt handle is on the other.

The sleeve is split In half and tig welded , soldered or even glued to the bolt body , the sleeve is made over size so it can be turned down to desired dimensions

 

[djgleeson]

That answers the question to why no one else called that out. I did not know that, thank you. But even if the interrupted cuts weren't an issue, would that additional operation even make hero's proposed process time-and-materials beneficial over indicating the action bore true?

 

[hero's machine]

That answers the question to why no one else called that out. I did not know that, thank you. But even if the interrupted cuts weren't an issue, would that additional operation even make hero's proposed process time-and-materials beneficial over indicating the action bore true?

The only way to answer that is to answer; can you indicate the action in faster than you can grab it with a collet? In truth, the bolt bore could be left alone as its way fat on clearance already.....and a savage head would be a thunk too.

 

[Aeon1]

How would you put the sleeve on the bolt though? The lugs are on one end and the bolt handle is on the other.

Many bolts have been done with a full sleeve. It's not too hard to heat up Remington handles with a torch to remove them. Search for gunsmith Stan Ware and his videos of the process.

 

[Bubb]

I find this interesting... I love reading the gunsmith threads. One could only guess that some gunsmiths do it this was and some do it differently. But if the argument is some prossecess don't lend themselves to being 100% accurate could it be said some (trued) actions are better then other?

 

[JJones75]

Here is my buddies fixture , the backing plate is 8"ODx1.25" thick , the adjustment section is 5"ODx5.5"long.
He has decided at the last min he may use something else so I'm waiting to set the cam pins. My personal fixture is much like this and is plenty rigid enough to thread and chamber barrels in.
Still have to make the inner collet yet

 

[jonaddis84]

Here is my buddies fixture , the backing plate is 8"ODx1.25" thick , the adjustment section is 5"ODx5.5"long.
He has decided at the last min he may use something else so I'm waiting to set the cam pins. My personal fixture is much like this and is plenty rigid enough to thread and chamber barrels in.
Still have to make the inner collet yet

Good God! You need a hoist to put that thing on the lathe? That had to be fun to machine, especially boring that hole if it started solid.

 

[JJones75]

It weighs less than the 3 jaw scroll chuck on the lathe (15x40 LaBlond). He was considering the system that Nathan Dagley has but can't afford it right now.

The back plate was cut off a piece of 8" 316 SS and the adjustable section was a piece of 5.125" 4140 , the machining is not bad at all considering I'm running it on a 19x80 LeBlond Regal.

 

[Boogaloo]

Why are you guys committed to making these fixtures out of steel? Back in the day when I was making chips for the aerospace world, very little (if any) tooling/fixtures were steel. Seems like the outer sleeve, and even the back plate on these things could easily be made out of aluminum and be as rigid as steel.

Anyone care to elaborate?

 

[JJones75]

I used steel cause that's what I had on hand , I'd have MUCH rather used aluminum and might if I make another.
For a device like this I think that the shear weight and mass of the fixture adds to its ability to shrug off some if any harmonics are caused.
We use a thousands of tons of aluminum at work (NASA contractor) but steel is still far stronger and more rigid that all but the most expensive aluminum alloys like 7068 and Lithium/aluminum.

I'm sure this thing made from 6061 would work great as well and damn sure be easier to make and install

 

[skeetlee]

when I made my action truing jig I offset my front row of brass tipped screws to the back row. im my mind if the front and back row were in line, there might possibly be some binding, while gimbaling the action around to find true. maybe not and im no machinist, but it was a thought so I went with it. my jig seems to work very well. lee

 

[Boogaloo]

Well before I saw JJones75 most recent reply, I went ahead and made my action fixture out of aluminum knowing that it would work just fine. I have a place locally that I buy aluminum in all shapes and sizes by the pound. The place I shop had some 6061/T6 rounds in the scrap bin so I snagged a few different diameters in various lengths so I can make a few different fixtures.

Here is my action truing fixture (spring collet design) attached directly to a D1-6 camlock back plate with 5/16 hardware. The gimbal set screws are 3/8-24 stainless. I counter bored the nose on the back plate .100" to positively locate the fixture primarily so that I can swap this fixture out with the one I am making for bolt work.

 

[Straight Shooter]

I really like the ones that are built right into the backing plate like that. For your bolt one I think you would be better off having it's own backing plate than having to take it apart to switch heads.