Author Topic: 1 piece monoblock (Read 4127 times)

PineyCreek22 · « **on:** June 16, 2012, 09:15:57 AM »

Has anyone built a solid 1 piece monoblock to screw custom barrels into for the SB2 receivers?

quickdtoo · « **Reply #1 on:** June 16, 2012, 10:32:43 AM »

Not that I'm aware of, Ed Hubel (hubel458) has done extensive work with SB2 shotgun frames and made MB receivers in his 12gaFH projects, but not for the H&R that I'm aware of.

Tim

Smokin Joe · « **Reply #2 on:** June 16, 2012, 10:39:58 AM »

Quote

Has anyone built a solid 1 piece monoblock

No, but I think about it 4 times a week! I thought about putting an enlarged lug on top of it so that the scope mounting holes could be made larger without weakening the block. I think the integral barrel lug would be great, too. Maybe even beef it up a little.

jeepmann1948 · « **Reply #3 on:** June 16, 2012, 02:12:13 PM »

It would be a simple project for a very well equipped CNC machine shop.Anyone with a degree in drafting,computer programming, CNC programming,experience in machine setup and tooling could produce one in about 25 to 30 mins of machine run time after the many hours of design and setup. For the shop to make any money it would require a run of several hundred to recoup the money invested and to make some profit. Someone with plenty of time and a well equipped home machine shop could build them by investing a lot of time and patience.
After the monoblock is finished it would then have to fitted to the receiver and limited to the pressure limits of the SB2 receiver.
But I do admit it is a neat idea

SEK_22Hornet · « **Reply #4 on:** June 17, 2012, 02:43:35 AM »

I'm just thinking out loud here, but what about investment (lost wax) casting to produce a monoblock? I know of at least two firearm companies that use the process to cast steel receivers (Ruger and Thompson). A 3d drawing would be needed, but I have seen foundries that will do small runs of lost wax castings. If a person was going to try this, I would think adding an integral scope mount would be a no brainer. Has anyone measured out and sketched up the barrel and lug dimensions?

PineyCreek22 · « **Reply #5 on:** June 17, 2012, 08:50:19 AM »

Thanks for the comments

I had not thought of the intergal scope mount, good idea. To tell the truth I am aways down the road on this project. Bought the steel 4142 pre hardened have used it before for gun projects and it machines well at a hardness of around 32 on the rockwell scale. I have drawn the monoblock on my cad system and although don't have access to CNC do have access to a lathe and mill, hacksaw and file. Plan to start tomorrow Lord willing. I will try to post pictures and drawings as I go along.
Piney Creek

Smokin Joe · « **Reply #6 on:** June 17, 2012, 09:07:18 AM »

Best of luck with you project!

I assume that this is a threaded stub? If so, any idea what thread size you'll use?

SEK_22Hornet · « **Reply #7 on:** July 20, 2012, 04:53:10 PM »

One problem with a monoblock design was brought up - how to do the extractor cut. I had a thought on that - what about milling up from the bottom to the location where the extractor sits then fillin in the cut out with a small block pinned in place -

trotterlg · « **Reply #8 on:** July 20, 2012, 05:23:43 PM »

Other than the "Cool Factor" what advantage would it have over a cut off shotgun stub? Larry

PineyCreek22 · « **Reply #9 on:** July 23, 2012, 05:33:42 PM »

In reply to Sek_22hornet I just noticed that in the great drawing the shelf for the latch could be possibly compromised, not saying that it would but could be. I believe that the monoblock idea has some practical advantages. 1 - it would be structurally stronger than a welded lug. 2 - less likely to have stress problems. 3 - could provide a better scope mounting platform. 4 - if monoblocks were commercially available the need to find a donor barrel and destroy it would be eliminated. 5 - finally, it would be easier for a handi owner or local gunsmith to add a barrel without having to pay all the costs for sending it to Remington.

nanuk-O-dah-Nort · « **Reply #10 on:** July 23, 2012, 08:37:56 PM »

I read some data on a jig, and a schematic to make a lug, and the technique for welding it onto an existing barrel.

it can be done, but not by me....

jkpq45 · « **Reply #11 on:** August 23, 2012, 07:45:27 AM »

Subscribed.

gcrank1 · « **Reply #12 on:** August 26, 2012, 04:58:26 AM »

You are limited only by your enthusiasm, after all, look what John Browning did.
Hope you make it work out!

LaOtto222 · « **Reply #13 on:** August 26, 2012, 05:15:43 AM »

I like the idea too. If the purpose was for a switch barrel setup, then head spacing would have to be considered. May i suggest a system similar to a Savage bolt gun? Have a flange that would mate into a groove in the mono block at the breech end with a barrel nut the would mate with threads on the barrel at the front of the mono block. The barrel would be inserted into the mono block from the breech end, the barrel nut over the muzzle and threaded onto the barrel to tighten every thing up. This way, every time you switch a barrel, the head spacing would be the same, it would not have to be dependant on thread torquing. The barrel could easily be indexed for the extractor/ejector and fore end screw or even iron sights.

Good Luck and Good Shooting

jeepmann1948 · « **Reply #14 on:** August 26, 2012, 08:17:51 AM »

One of the issue of inserting the barrel thru the breech end would be the forearm lug. How you going to get it in the monoblock with it protruding down? personally I would do it like a Savage with the barrel screwed in from the front. To keep it indexed correctly witness marks would suffice well for depth and the extractor/ ejector for vertical alignment. One thing you would want to do is make sure the nut is on the barrel before the forearm lug is welded on or another problem will arise very quickly

. The more I chipher on this the better a custom underlug and bedded scope rail sounds

But I still like the idea
George

nanuk-O-dah-Nort · « **Reply #15 on:** August 26, 2012, 09:42:47 PM »

if the "Nut" is screwed onto thread the same as a Savage, then the issue is moot, as you can screw it on from the breach end before inserting the barrel into the stub.

PineyCreek22 · « **Reply #16 on:** August 27, 2012, 07:03:17 PM »

A big thanks to all who have offered encouragement and ideas. Between my lathe/mill breaking down and eye surgery it has taken a little longer than planned. I will post some pictures of progress soon. Regards, Piney Creek

quickdtoo · « **Reply #17 on:** August 28, 2012, 04:51:45 AM »

Ed Hubel has monoblocked an H&R in his 12ga FH projects.

Tim

http://www.gboreloaded.com/forums/index.php/topic,79991.msg1099245975.html#msg1099245975

PineyCreek22 · « **Reply #18 on:** September 07, 2012, 07:01:20 PM »

Thanks for all the ideas and encouragement. Here are some pics of my progress so far. A long way to go with hurdles I haven't even thought of. Piney Creek

ncloader88 · « **Reply #19 on:** September 07, 2012, 07:07:42 PM »

Great to see your progress! Are you set up to produce these for sale or is this mainly just a personal project? Either way keep us posted, this idea has lots of potential.

SEK_22Hornet · « **Reply #20 on:** September 08, 2012, 03:10:27 AM »

Looking good Piney! Just curious what kind of machine you are using - I get the impression it is a lathe / mill combo like a Smiithy. Also, the stock looks like it might be long enough to make 2 from - is that your plan?

PineyCreek22 · « **Reply #21 on:** September 08, 2012, 07:57:16 AM »

Right now this is a personal project. I do not have the capability to produce the quantity needed to go commercial plus all the liability questions but the trail is being broken for those who wish to follow and I will be as much help as I can. Yep this is a Smithy "Granite" - very light and slow but we have done some neat stuff on it. As a gunsmithing lathe/mill there are better ones for just a little more money from Grizzley. The billet that I started from was large enough in diameter to include the bottom stud and long enough to cut into two pieces when the profile was finished. By the way the material I used is 4142 - tensile strength 140,000/sq" and yield strength of around 90,000/sq". A little hard on tooling but do-able. Piney Creek

quickdtoo · « **Reply #22 on:** September 08, 2012, 08:25:35 AM »

Nice work, thanks for the update.

Tim

jkpq45 · « **Reply #23 on:** October 05, 2012, 06:11:23 AM »

I'd love to hear an update, if one is available.

PineyCreek22 · « **Reply #24 on:** October 07, 2012, 05:49:22 PM »

Hello JKPQ45, Thanks for asking about the monoblock. As of the moment I have drilled and reamed for the hinge pins in 2 blocks fitted them to receivers and bored the tennon hole ready for threading. I will be ordering a .357 barrel from Green Mountain tomorrow morning for the first receiver. If everything works with that one my second barrel will probably be in 38-55. Tennon dia. will be 13/16 with 7/8-14 threads and a 1-1/8" dia. shoulder against the monoblock. I will be posting some more photos on the forum about the end of the week if everything goes OK. Again, thanks for the interest and if I can answer any question I'll be happy to do it.
Regards, Piney Creek

jkpq45 · « **Reply #25 on:** October 08, 2012, 07:12:46 AM »

I couldn't remember if you had planned on installing a shoulder on your barrels or if you were going the barrel nut route.

Sounds like awesome progress! Once the MB's done, installing new barrels should be much cheaper and more quality than factory fitment of new ones.

Oh yeah, and obligatory "how long is that .357 Mag barrel going to stay 'short-chambered'" comment? With all the Maxi fans around here, I'm surprised I'm the first to rib you about it. :-)

PineyCreek22 · « **Reply #26 on:** October 08, 2012, 03:46:08 PM »

Good question JKPQ45 I have even asked the question myself! The big problem is that I have 2 sb1 receivers that are being used for these prototypes and I hesitate chambering a barrel for a maxi to be used on a sb1. However, I have no doubt that a maxi will appear eventually on a sb2 in my cabinet

Regards Piney Creek

PineyCreek22 · « **Reply #27 on:** October 11, 2012, 05:47:50 PM »

Ordered a barrel tuesday, hope to get the receivers threaded and drilled for extractors within a week. Still a long way to go and problems to solve. Hope these photos will give you an idea the direction I'm going. Yep, this is an awfull heavy monoblock to put on a Sb1 receiver but for right now thats all I had available. Future plans involve Sb2's with heavier calibers. Anyone who has ideas for improvements or critcisms (I have thick skin) I would appreciate. Best regards Piney Creek

geezerbiker · « **Reply #28 on:** October 11, 2012, 07:25:52 PM »

Sorry no criticism. I think the octagonal shape of the monoblock makes it look classy. If I had the equipment and skill to do that, I'd probably make one in .33 WCF....

Tony

cwlongshot · « **Reply #29 on:** October 11, 2012, 11:38:18 PM »

Quote from: geezerbiker on October 11, 2012, 07:25:52 PM

Sorry no criticism. I think the octagonal shape of the monoblock makes it look classy. If I had the equipment and skill to do that, I'd probably make one in .33 WCF....

Tony

VERY NICE!! I agree it is "Classy"

Im watching with anticipation!

CW