Materials Advice Needed

C

crb

Ray Brooks
I am building my version of the Shelley Davidson Tinker Toy. For the forend I am designing a free floating set up similar in concept to a free float tube as used on AR15's.

I am going to replace the recoil lug with an extended tubular sleeve that will extend forward over the bbl for about .5" to 1". My current plan is to thread the outside of this sleeve to accept matching threads on the inside of the free float tube. I may also make a smooth sleeve and see if a nice tightly fitted slip joint will suffice. On either set up I will use a pinch bolt to lock the free float tube to the sleeve.

My question is what material to use for the sleeve ? I need something about 1.75" to 2" OD [ solid rod not tubing ]. The options are:

1-Gray Cast Iron

2-Malleable Cast Iron

3-1018 Mild Steel

4-4130 Rod

Drill rod is too expensive. The two irons are the least expensive and the mild steel and 4130 are not too expensive.

Taking into account strength and machinability which of the 4 would be the most suitable and easiest to work with ??

Thanks
Ray
 
I would use 12L14 or 416 SS. I would not use 1018 or cast because of machining qualities of them. I know you can find 1018 anywhere but I really dislike trying to do any machine work on it.
So of the choices listed I would go with 4130 but would prefer 12L14.
Another possibility is 7075 T6 aluminum, it machines real nice and is surprisingly strong.

James
 
6061...low weight,machinable..
you are eliminating the recoil lug...so why go heavy
as in copy the ar's
mike in co
 
The aluminum float tube will be threading onto this sleeve. The threads will be very fine. I am worried that alum on alum will gall. Also there is the issue of the bbl shoulder bearing against the alum and transferring metal.
 
go pull an ar apart. the bbl(steel) is held in place between an aluminium machined forging and steel(normal) or aluminium round nut. there are two pc and three pc free float tubes. some have a nut, adapter, sleeve others have nut/adapter and free float tube. either tightened down or set screws to clock the tube.

mike in co
 
crb said:
My question is what material to use for the sleeve ? I need something about 1.75" to 2" OD [ solid rod not tubing ]. The options are:

1-Gray Cast Iron

2-Malleable Cast Iron

3-1018 Mild Steel

4-4130 Rod

Drill rod is too expensive. The two irons are the least expensive and the mild steel and 4130 are not too expensive.

Taking into account strength and machinability which of the 4 would be the most suitable and easiest to work with ??

Thanks
Ray
Click to expand...


Gentleman, did you ever heard of 4140, 4130, 4340 seconhand hollow bar?

Gentleman, would you believe, it may be as cheap as the mild steel bar.

Con
 
Last edited by a moderator:
A barrelmaker may give you a short piece of 2" diameter 416R. I'd go with that, easy to machine, looks nice, adequate hardness.
CrMo would be my second choice.
Ebay is a good source for materials.
 
Jackie,
You will have to do better than that.

I have given this a lot of thought and I don't see any safety issues. It will leave the bbl totally free floating just like a good BR stock. It will be easy to get the action and bottom of the forend all nice and level. The free float tube will have most of the upper surface machined off so as not to interfere with the objective bell of the scope and to allow airflow around the bbl. I will add a 3" wide glide plate at the front.

Thanks
Ray
 
Square peg...

Hey Ray,

Why not use a rectangular tube? It could ride the bags easier and would be less susceptible to rotation from the bullet imparting forces on the barrel...

Just a thought.

Or does Jackie know more than what you are letting on...:eek:
 
I think it will be easier to stay with square tubing and add the 3" nylon glide plate to the front to ride the bag. A round tube would be easier to mount to the sleeve but be harder to adapt to the bag. I am about to order some stuff from MSC and may add some round tube to the order.

I wish Jackie would post his reasons.
 
Ok

Look, Shelly was a good friend. He was a nice a guy to be around as you could hope for. His untimely death left us all a little diminished.

I feel very uncomfortable talking about some of Shelly's ideas. He put a lot of time and effort into them.

I sat beside Shelly several times at Registered Matches when he shot that Rifle. Let's just say that I would not build one, and leave it at that.
........jackie
 
Jackie,
Thanks for replying. The minimalist idea is just one that always has resonated in me. I like thinking outside the box and trying unconventional ideas. I am also not afraid of going my own way which is why my set up will be much different from Shelley's.

I will post updates as I progress with this project :D
 
Gentleman, would you agree, that life goes on and ideas don't slow nor stop.

Con
 
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