Takedown 98'

[slseacrist]

So while I wait for a barrel for my Montana Rifle Comp. 300 Wby project. I though I would get started on trying to make a takedown 98. So fair I have the jigs made and have cut a practice barrel. I am now ready to cut the action, but I am going to make a blank before I ruin a perfectly good action. Hear is how it has gone so far.

 

Cutting barrel holding jig (before milling was started)

 

Starting to remove unwanted threads

 

Jig Finished and ready to work on threads

 

Milling the threads

 

Finish practice barrel, next time I have to cut a few thousand deeper, the bottom of the thread just barely show up. Nothing a little time with a file would not fix though.

 

The Jig to hold the action for milling out the threads.

 

So I am looking for comments. My greatest concern is that it will not stay together with over 50 % of the threads removed (my Calulation are about 56%, If I did it right). I do not plan to use high pressure load. I also plan on using a Turk, so I have though of removingthe exsiting threads and recutting them with more threads per inch. If so I would consider using a acme or other thread type. Thoughts? Thanks SS

 

[tinkerfive]

I don't know what caliber you are planning on.

However if it is something in an X-57 case or smaller....

I would just make the observation that if you were to use a

Turk 03 you get an extra thread & a half or perhaps two

compared to other 98 type actions because of the longer

shank length.

 

Tinker

[ken98k]

The problem with these as I understand it is the threads wear and you have to keep tightening little by little over time.

Mabey square springfield type theads?

[GA1dad]

I know you are looking for suggestions, but I can tell from the pics that you are far superior to my meager abilities, so I won't insult you. What I will say though is that I am quite impressed! It does appear well thought out. Please post progress!!!

 

Good Luck, Jay

[cold shot]

SS I've made a semi take down M98 by taking large washers big enough to fit on the barrel 1/2" from the receiver. Then I mig welded it to the barrel ,ground it square on both sides and made a open end wrench to fit it. I use the action wrench too. I am then able to swap out barrels at the range. 300win mag, 8mm/300win mag, with another bolt I'm also able to use my 8mm/06 barrel . It works pretty good for me. Dave

 

P.S. I don't have a digital camera or I would take pics to show ya.

[roscoedoh]

If this method fails, put the receiver in a lathe and machine the thread completely out of it. Then machine locking recesses into another barrel and deepen the chamber accordingly such that the barrel will sit far enough back into the receiver to allow the bolt to lock into it instead of locking in locking recesses in the reciever. This is method Dakota uses for their take-down rifle - its a lot of machine work and whole lot of time, but since the bolt locks up on locking recesses in the barrel, it will headspace the same everytime.

 

I have a picture of this somewhere but I'm not on my home machine right now so I can't post them. I'll try and dig them up tomorrow night when I get home.

[slseacrist]

thanks for the great response

 

tinkerfive: I was thinking of 250-3000, 257 rob. or 308. I do have a couple of turk 03's. And I was considering using it. Fortunately they both have the same size threads.

 

kenak2: wear is something that I have though about. My first question is how much wear should I expect. Many of these rifles have already been used for thousand if not hundreds of thousand of rounds, and though they have wear, many still work and are within expectable specs. As of right now my thoughts were to make spacers at half and all (-.001) of the difference between the go and no. Cut the chamber tight. Then these would be sottered onto the front shoulder as the wear point is approached. After the second one was added, the barrel would be set back one full turn and chamber re-cut I guess that I really do not think that a gun of this type will ever get enough wear. Even if used every weekend, it would take close to 20 year to go though a 1000 cycles. I would like your continued thoughts; I am overlooking a major issue.

 

 

strait shooter: If you ever get access to a camera I would love to see your project. The evolution of this project is to eventually make a three barrel set, on a different action, in 250-3000, 308 and 358 Win ( or maybe the new federal round, but I need to do more research on it)

 

roscoedoh: I will look forward to seeing the pics of the Dakota action. I new of this action, but never have seen how it works. It sound like I may want to revaluate by project. Machine time is not a concern, but making a great, esthetic, functional peace of art is.

 

Thank for the comment, again. I will keep you all posted of the progress. SS

 

[z1r]

The cure for compensating for wear is a plate where the barrel meets reeiver that has a couiple of screws that will cinch things back up again.

[BobVZ]

Looking at "Bolt Action Rifles" by de Haas, The Dakota "Traveler" employs a split receiver ring with integral clamping block on the underside. Once you slide the barrel in you tighten the sleeve around it to lock receiver and barrel together. The rest is how roscoedoh described. The same article claims the Germans developed a system of interrupted threads for the Mauser that also used some sort of clamping sleeve on the receiver so the wear issue could be addressed. In effect you can negate the wear issue by having a "loose fit" when you engage the threads, then clamp the receiver ring around the barrel mating them tightly together. Maybe someone else has some photos of the German system that you could employ.

[Doble Troble]

Damn fine work, slseacrist!

 

It seems to me that a minimum headspace chamber will be safe for a long time despite wear.

 

Accuracy is probably a separate issue.

 

You're really onto something and you've got the damn wheels started in my sporterizing brain!

[z1r]

Damn fine work, slseacrist!

 

It seems to me that a minimum headspace chamber will be safe for a long time despite wear.

 

Accuracy is probably a separate issue.

 

You're really onto something and you've got the damn wheels started in my sporterizing brain!

 

 

Correct, unless you are sitting in front of the TV everynite taking it apart it should remain tight for a while. teh two screws I mentioned will push against the receiver plate and in effect tighten the threads, no clamps needed.

 

here's a pic. It also shows the central retracting locator pin that keeps things from turning.

[cold shot]

Hey Slseacrist, I got my gears turning on another way to make a break down M98. I just wished I could draw. I couldn't draw 2 straight if I taped the pencils together. We have a scanner up here with our computer. Mabe I could get my daughter to make some drawings, then scan them then post 'em. What do ya think? Dave Can't hurt!

[slseacrist]

Well after being laid up all last week with that bug going around I got some shop time this afternoon.

 

First I made a test action. I mounted in on the mill and set about removing the threads. I had done some calculations a few weeks ago about how much angle to remove. Using three-week-old calculation was my mistake. I over cut the angle so the action threads are slightly undersized in comparison to the threads on the barrel. Fortunately I only need to turn my test over for another go.

Anyway the process clearly works, the two lock up great. Second problem is the barrel over rotates by about a 15%. I should have figured on that, considering about half the threads are now gone.

 

 

So as a result of my test I have leaned this. First, remove the thread for the action. Second, thread the barrel and fit it to the action mark BDC. Mounted it on mill, compensating for the 15%. Remove the threads, Remount in lathe, check for proper alignment, set back thread if necessary and chamber. The only major issue I see with this method is that I have to hit the chamber right the first time.

Comments, thoughts, anything I have overlooked?

 

[tinkerfive]

How do the threads over rotate by %15 if you have engaged the torque shoulder?

 

Seems to me as if something else prevented final rotation when you did your layout.

 

Once the torque shoulders meet that should be what stops rotation.

 

Maybe I'm missing something!

 

Tinker

[cold shot]

Say, SS, I was thinking that if you have a locking ball that is spring loaded, like what holds sockets onto your ratchet, wouldn't it also hold the barrel from moving once it's locked? Dave

[AzRednek]

To say I’m impressed is a real understatement!! I admire your skills and certainly wish I was capable of taking on such a project or even making an intellegent comment on the project. I’ll be looking forward to seeing pictures and hearing of the progress.

 

About 6-7 years ago in another group, pictures from a Savage take down project was shown. It was made to shoot Hollywood blanks, fit together or taken apart easily by an actor in front of a camera and not fire live ammo. Whomever it was that posted the pictures claimed he was going to build another Hollywood scoped take down rifle with a battery powered spark to shoot a propane muzzle flash but I don’t know if he ever completed it. Just out of curiosity I asked what kind of money the movie studio paid or how much he was selling it for but he didn’t respond.

 

 

[slseacrist]

Thank you for all your comments.

I redid my calculation and I will be running one more test, to make sure that the 60 deg slices are truly 60 deg. Then onto the really thing.

 

tinkerfive

I think I agree with you, that I made a mistake when laying out the work. My concern is that the action will become tight (face crushes against the shoulder) at a different point after the all the threads are removed. I think that I was out thinking the problem. I was worried about the friction between the threads. When in reality you are correct the shoulder is what stops rotation. I think that by reversing my operation, action first then barrel. This will be a much more precise method. The key issue is, that the thread that remain in the action completely lock up with the remaining thread on the barrel. On my test the thread over rotated so about 15 % of the thread was not locked up with the threads that remained.

 

strait shooter

The ratchet idea is a good one. I am still bouncing ideas around in my head for the locking method. One idea was to make linkage that would use a hinged for plate, but I think that is to complicated for proto type. Most likely I will use a simple method like browning did on their 22 auto.

 

As for the issue of wear. I like all of the ideas. Two spring seem to be the best idea, that coupled with the ratchet idea, may work out.

 

My other idea to compensate for wear is.... This may be to complicated to express it in text format.

On the barrel I would cut full threads that are say .125 (what every I can get way with for cal. and action type) smaller then the major dia of the action threads. Then thread the barrel to any TPI, most like a high TPI, say 20 or more. Then make a adapter, similar in idea to a Female Female pipe fitting. This would thread on the barrel ( with full threads) On the outside of the adapter would be the threads to match the Action, cut in the same manner as about. The adapter would be held in place with a setscrew or silver sotter. As the wear increased, the adapter would be screwed out maintaining headspace and shoulder lockup. This would require a lot of machine time, but I think might fix the wear problem.

 

 

Anyways, comments?

 

PS AzRednek, I wish you new how much they wanted for a prop. I have considered selling this gun off when it is complete and proven to be a worthy design.

 

PPS strait shooter Northern CA????

[cold shot]

SS I'm going to my shop tomorrow to work on my daughter's truck, work a little on our taurus, then I'm pulling down my vz24 to build another wildercat. I'm thinking of a 8mm/08. Just for the fun of it. As for northern Ca, I'm east of the bay area and almost on your back door. Dave email me ok. see my profile.

[~DEVO~]

What is the status on this build?

 

Strait shooter; any luck posting pics of you semi break down rifle. I would to see pics of that rifle.

[slseacrist]

Unfortunately almost nothing.

The last thing I did was try to cut out the thread on the action. I learned that the jig I had build over stressing my rotary table. Solution, buy a high grade table, or redevelop the process. As of right now I am going to try my double female fitting approach (explained above). I should have more time in the next couple of months to get back to work.

 

My many reason for so little progress is my MAIN job is as a Auto and Robotics teacher at a High school. Cal. has a big push to bring more Industrial Tech Classes back to main stream public schools. I have wanted to start a CNC machining class for quiet a while. So I want to just on the money wagon the state is pushing, so for the last three month I have been working on a $250,000 grant to start a full CNC machining course. Between writing the grant, making contacts with local machine shops and supplies, and all my other duties, my own shop has gather a nice collection of dust. Fortunately the grant was submitting two weeks ago, I spent spring break in Hawaii, and now I can get back to my own shop. I better one of my clients is screaming for me to get his stock done.

 

I have been so busy that I have not been able to hand around the board much either

 

SS

[Clark]

Many of the guns made 100 years ago were take downs.

My brother was speculating last week that it was because the car was not popular yet.

The rifle or shotgun had to fit on a horse, bicycle, or luggage on a train or ship.

 

I just got back from a varmint hunting trip, and I filled the car to the ceiling with stuff.

[slseacrist]

Ok after getting a little push from Devo and my wife throwing a baby shower, meant I was "forced" to spend all of Saturday afternoon in the shop. Needless to say I put up a great fight.

 

So I got a lot done and was able to spend a couple of hour on the takedown project. So hear is a recap of what I have done so fair. I removed all the threads for the action, then recut left hand threads (18tpi in the action). So it would be opposite of the forces placed on the action with the removal and replacement of the barrel. Next I cut threads on the out side of blank. In the spacer standard small ring threads were cut. After that I moved to the mill and set the blank on the rotary table. I cut the extremes of each cutout. Then I step drilled, 2.5 deg at a time the spaces between. I was glad I had power feed on my Z axis. Last I parted off the needed amount.

 

The trouble came when I tried to screw the spacer in. I had made a close tight fit and cut my handle off. So now I have to make a tool to screw it in. Next I am going make some test blanks to make sure that the threads will line up properly when they are removed. Then I am going to make cut the threads on the 30 cal barrel. Chamber in 30-06 and crank it up to the highest chamber pressure possible. Then strap it to a board and give it a test fire by string. Because this is an untested system I think this is prudent.

 

Comments always welcome

 

 

 

SS

[gun nutty]

Wow!

 

Very nice and well thought-out. I'm looking forward to seeing how you integrate things into the forearm wood.

 

[~DEVO~]

I am here to push you some more Slseacrist...

I was wondering, are you going to weld or silver solder the threaded ring into the action? I take it the barrel will only require a 1/3 turn to catch the threads? Are you going to use a set screw?

 

The project is looking good.

[slseacrist]

OK Boys

The reveres thread is intended to allow for the barrel be tightened after wear occurs. To hold the spacer for moving, I plan to put a small set screw BDC. Then when wear adjustment is needed you looses the set screw turn the spacer enough so the go and no go will fill properly. And re tighten.

 

As for the forearm, I want to use a latch the comes on the 99 savage and modifyit to a strait line use. The latch will pulls a pin out of the butt stock and allows the barrel to rotate 1/3 a degree.

 

More to come soon .... I hope.

 

Scott