designing/machining own action

[fusionrider]

OK major wrench thrown in the project.

Today I was scheduled to run the wire EDM that I was told had the capacity to do 6"......well It has the cap. of ~4.75". My piece was cut to 5.75 as planned but figuring it would break budget if the EDM wasn't free. I cut it to 4.625 and proceeded to have the profile cut.

The worst case would be that this short of action won't be doable at all and I will have to scrap it,if so I am only out $43), but I see this as sort of a challenge now. How short is too short?

I can cut back on the feed port by .5 or more and the tang isn't a really crucial dimension to keep either. I can shave some out of the locking lugs and barrel threads,and still stay within safe limits, but this would be a last resort.

Any other Ideas for shaving length?

Sawyer

 

[2700tenx]

Fusionrider,
Too bad you don't live closer. I'm a moldmaker with several years experience with a wire EDM. We have one with a height capacity of about 15". Would jump at the chance to be involved in a project like this. Good luck, I'll be watching for future developments, for I would like to do something similar someday.

 

[fusionrider]

Here is what I have so far

The pictured bolt Is a 700 SA and the 221 round pictured has a 68gr hp seated to sierra OAL length.

thanks,
sawyer

 

[Tucker65]

Wow,

That looks great, I have been wanting to build an action for a 50 BMG for some time now and this is getting me motivated to get started on it.

I hope you are getting good drawings of this to share with us. I might be interested in building one of these for a new varmint rifle.

John

 

[fusionrider]

I threaded the front of the action today and everything turned out good. The 17-4 was amazing to cut and the finish on the threads is great

Sawyer

 

[strictlyRUM]

How long ago did you send in for your form 1? I just sent in another one and was wondering what the wait time is right now with all the people rushing to buy/build with Obama at the wheel now?

Jason

 

[fusionrider]

Im sorry I don't have much experience In that arm of our government but if its like the others have fun waiting.


I have no intention of ever selling this action.

That said, nothing I have read or heard has told me that I need any forms or authorization.

http://www.atf.gov/firearms/faq/faq2.htm#a6

If I am mistaken by all means please tell me!


thanks,
Sawyer

 

[strictlyRUM]

Nope you are right. The way that reads if you plan on owning all its life you dont need a form 1. I was told different by our sherrif. I better get crackin then. I have never owned a rifle very long though. Maybe I should just get the stamp?

Jason

 

[gamma]

Hi there,Ive been watching this topic for quite a while now and I must saw,WOW.Absolutely fabulous piece of engineering,Im really impressed.Its something Ive always thought about doing but never really got the motivation to tackle such a task until now and I must say,this has kinda got me thinking.Im a Toolmaker/Injection mouldmaker and I have access to all of the neccessary kit needed to pull off a project like this but I still think it wouldnt go without the guidance of someone whos already done it.Im wondering what did you do after EDM,wouldnt the surface of the profile be hardened from the wire and need annealling or do you just go straight ahead and heat treat it above the temperature of the wire erosion and let that take care of it also how is warpage minimised.These are all the things I can see as problems,or maybe not as when us guys are doing anything that involves heat we usually allow for a little warpage and leave on a few thou so we can then finish off with a light surface grind,I dont see any room for warpage on an action.Just wondering how the greats get around that one.Im hoping Preston might shed some light on this one also.I wish you every success with your end result.Great job.

 

[butchlambert]

Gamma,
I am not a metallurgist, but I just had some trigger parts cut with wire and I just went out and hit it with a file. No problem to file and no problem to drill and tap. He may have mentioned the RC of his metal as machined. I believe that it is hard enough to not need additional heat treat. I believe that is one of the secrets of a good straight receiver and that is machining it in the hard condition.
Butch

 

[ArtinNC]

Fusionrider,

Looks first class, good job.

ARt

 

[prestonpritchett]

Its my understanding also that you don't have to do any paperwork on your first one as long as you don't sell it or make a 2nd. But as we all know the big kids get to make the rules that we play by. It is what it is.
Gamma
As far as the "greats" you have to be referring to someone else. We are just Okie farm boys that figured out there was a easier life than hauling hay and getting kicked in the gonads by cows. Although I still like watching them steaks walk around.
When we cut the inside of our action with the wire if you don't skim it there will be a "scale" on the inside of the action, it will also not be perfectly straight. We do a rough cut and then 5 skim cuts per action to get it straight and get the surface finish we want. The 4th skim takes off .0001 and the last one is at the same offset. We spend 3.5 hrs per action cutting and 12 min per action droping the slugs,inside)out. It cost us more but it is the best we can do. Most action makers broach them which can be done for around $20 or so. The next level bores the inside and then wires the raceways.
We do the bore and the raceways with the wire. After all in our opinion just wiring the raceways does nothing for the straightness of the action to center line because your bolt should be resting on the bore when it is in your action. We use the same fixture in the mill to do the surface your locking lugs rest on, the threads, and the surface your barrel rest on. This ensures it is as square as it can get. The next time your gunsmith barrels up a rifle, have him screw your action on hand tight to your barrel with it still in the lathe. Now take a indicator and check the inside of your action while spinning the chuck with your hand. If the front of your action is not straight with the center line of your bore you will see in in your indicator. If you will role your round action on a PC of glass or better yet a granite table with a light on the backside you will see if it is straight on the outside or not.
We rough machine the actions removing most of the metal and then having them heatreated. All surfaces of our action are machined hard at 40HRC. As far as warpage goes it is my understanding that if you harden it and it comes out 50hrc,this depends on the steel type etc) and your goal is 40 you have to put it back in the oven and,draw) warm it up to a temp below the temp it was taken to to make it hard the first time. For conversation lets say you draw it back at 800deg to get to your goal of 40hrc. At a later date as long as you don't get it close to this temp there won't be no measurable warpage occur.
As far as machining a 40HRC,hardness Rockwell c scale) metal. If you spend the money and buy a good grade of carbide that is coated, 40 is not a problem and sometimes it is easier because it will make a chip. Some of the gummy steels are easier at 40 than 20. When we machine the outside of our mod 591 action we use a 1/4 ball nose end mill that is Tilan coated. The coating turns to ceramic when it gets hot. If we use coolant on this tool turning 12,000rpm and running 240ipm,inches per minute)it will last 3/4 of the surface of a action. If we turn the coolant off we get about 5-6 actions from one end mill.
As far as the metal 17-4 that Fusionrider chose. It will have very little warpage because of the type metal it is. Some metals twist like a snake and others are more stable.
I think it is great Fusionrider done this. He will have a rifle he made with his own two hands and hopefully the laws of our land will allow him to hand it down for generations to come. I didn't mean to hijack the thread or type a commercial. If you guys ever get in Oklahoma we would consider it a honor if you would stop in and see us.
Thanks
Preston

 

[gamma]

Thanks preston,great reply.Id love to drop by if Im ever in Oklahoma to see your outfit,thats something to think about.

 

[KBattenbough]

Fusionrider
That is a great action, and work you have there, congratulations!and im watching with keen interest to see how you cut the bolt lug cam clearances inside it.

Preston

When we cut the inside of our action with the wire if you don't skim it there will be a "scale" on the inside of the action, it will also not be perfectly straight. We do a rough cut and then 5 skim cuts per action to get it straight and get the surface finish we want. The 4th skim takes off .0001 and the last one is at the same offset. We spend 3.5 hrs per action cutting and 12 min per action droping the slugs,inside)out. It cost us more but it is the best we can do. Most action makers broach them which can be done for around $20 or so. The next level bores the inside and then wires the raceways.

Im a little confused by this, do you mean the 'outside' of the action? if you are cutting out slugs and then 5 skim cuts before the raceways, what profile are you cutting out?

Thanks
KB

 

[prestonpritchett]

KB
The wire only cuts out the inside of the action.
We drill a 1/2" thru hole in the center of our action before it is heatreated. Then after heatreat we machine all the outside dimensions of our action. Then it goes on the wire machine and we cut the profile of the inside as in the raceways and the bore. This is done with the rough and 5 skims. Now everything is to size on the inside except there is a .030 tab that still holds the slug in. We drop it out last in order to keep the wire machine running 24/7. When the .030 is cut this releases the inside slug to drop out. The slug has the 1/2" hole thru the middle and the wall thickness is around .1 where the bore is and where the lug is it is thicker. If I am still clear as mud please let me know and I will try to take some pictures that will explane it better. Today there is 12 operations to making our action. When the Intergrex comes on line it should take it to 3-4 operations.
Fusion rider
What caliber are you planning on?

 

[KBattenbough]

Thanks Preston
All clear now.:thumb:
KB

 

[fusionrider]

When I cut my action on the EDM,both inside and out) I chose a fine feed that took 2.5 hrs on the raceway and over 5 hrs on the outside profile, one pass each. The dimentions on both are near perfect and I haven't seen any sign of kerf or deflection. While one pass may not make things absolutly perfect I personaly didnt need the profile to be +/- .00002 when my threading and chambering will only be good to .0001 But that is my expectations. I am sure being a comercial action builder you are held to higher standards by the consumer and it is nice to know you are doing things the best you possibly can.


The intent is to make a 221 fireball, and that is most likely what it will start life as. I have been looking at the VarTarg and maybe a .17 of some sortfor later chamberings.

Progress has slowed because I am in the process of finding a bridgeport so I can do all of the finishing work at home instead of at the local voc college which is on christmas break!
still need their horz. mill for the slots in the rail though.

thanks,
Sawyer

 

[gamma]

Preston,some pics of the process would be brilliant to look at and Im sure all of us would be mega inspired.Im a little dull on what exactly your explaining,although I shouldnt be.Best of luck with the Integrex.I take it your refering to the Mazak Integrex,thats the one I spend 40 to 100 hours on each week,it loves tooling and tooling suppliers love IT.I wouldnt like the annual running costs for this baby but it sure is a mega piece of kit.Im thinking that this could do away with the EDM altogether as you could use a broaching tool here to take out the locking lug recesses.

 

[vonb]

Preston/FusionRider,
I have to commend both of you for different reasons. Fusion, it looks like you are doing the right thing by measuring twice and cutting once and I've throroughly enjoyed this thread. Keep us posted as you don't see this type of information every day.

Preston,
I've enjoyed the information you posted as it confirms why I went with a Surgeon action for my build. The fact that you help someone in the community says a lot as there are others that would turn their back. If I'm ever in OK, I'll buy you a beer.

 

[gamma]

Fusionrider/Preston,it seems like an age since we,ve heard anything from you both,I hope its because your both too busy making progress in your ventures.Im always watching to see if theres anything new on this thread,its the first thread I look for every time I log on.Fusionrider,I cant wait to see how far youve got so far and Preston,a look at some pics would be awsome.Im particularly interested in how you explain about dropping the slug inside out for so many passes to even up the raceway.Happy new to all who enjoys this thread,it has to be the most interesting thread yet,it has been for me anyway.