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Gunsmithing Need help with DIY project

Dylan in AZ

Shooting Addict
Full Member
Minuteman
Dec 24, 2010
1,218
4
Arizona
Hey guys,

I have an idea brewing and I need your help to figure out what the best way to go about shaping the "curve" into a blank section of picatinney rail that contacts the action itself. It will be used for a scope base. I don't know all the techinical, smart-person, terms to search the question well enough to find an answer on Google so here I am. I hope you all can understand what I am trying to convey.

I don't have a mill to do the work with. So in my mind, this would be akin to opening the barrel channel in a stock via the wooden dowel + sandpaper method. In fact, would that work well enough to get me in the right direction? I suppose It wouldn't be very precise, but the mount could be finished off with some bedding compound and a good jig correct?

Thanks in advance!



Dylan
 
Re: Need help with DIY project

How about posting a picture of what you are talking about and Ill see if I can help you out.
 
Re: Need help with DIY project

Patience of a saint. What your wanting will require it.

Try this maybe:

Get some wet/dry emery in 80~100 grit.

Wrap it tight around your receiver.

Make a jig/fixture that'll align the rail parallel and start stroking.

You'll get more chicks too cause by the time your done you'll have arms like popeye.

Have fun!

C.
 
Re: Need help with DIY project

How much material are you looking to remove?

Why not get some sacrificial screws the same size as the receiver holes and cut the heads off simply to make some alignment rods. lube em up good and build a dam around the area with some modeling clay, lube the receiver and lay down some JB and then set the rail into the JB with the screws in the receiver thru the rail.

I know its not the best way, and I am sure looked at like the bubba way, by actual smiths but hell it would work.
 
Re: Need help with DIY project

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Junkman1967</div><div class="ubbcode-body">How about posting a picture of what you are talking about and Ill see if I can help you out. </div></div>
Junkman,

This blank section of pic-rail needs to be drilled, and contoured for the specific action it is to be placed on. It is completely flat on the underside, and needs to become curved to accept the radius of the action.
265080.jpg

Now this is where it gets a little bit odd.

A fellow member here had posted up pictures of his 40x which had a unique base on it. It allows the scope to be mounted/removed while still having the mount for match sights built in. I spoke to him about it via PM's and neither of us know who made the piece for there is a lack of identifying markings but due to tooling marks I have ASSumed that the previous owned probably made it himself. The current owner said this ASSumption would be a fair one to make. At any rate, it doesn't really matter. It would be perfect for what I want to do, but I have a different action. So I need to figure out a way to change the design slightly and adapt it for use with my own narrower receiver.

Here are pics of the base that inspired this question:
2ia6cmc.jpg


eq9lkp.jpg


mauex1.jpg


I hope you don't mind me posting these Jeff, if you see this and wish them removed just say the word.


I have been somewhat misleading so far though, as I wouldn't actually be shaping the base itself, but rather a piece of stock to go under and act as a wedge between the action and the base. It appears that the base pictured above is a single piece; however I don't have the tools to replicate that. So, I figured a good piece of steel sheet metal filed down to fit under the blank pic-rail pictured at the top of this post with the same type of mount sticking out of the side would be a fun project for me. I have a much simpler way of mounting the sight on the existing base already formulated, but I wanted to know just how difficult this would be as I know it would look much better and be stronger than the other method I have planned. I hope this all makes sense and I apologize for the shortness of my OP. I was very tired last night and didn't have the energy to be this detailed
smile.gif


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Patience of a saint. What your wanting will require it.

Try this maybe:

Get some wet/dry emery in 80~100 grit.

Wrap it tight around your receiver.

Make a jig/fixture that'll align the rail parallel and start stroking.

You'll get more chicks too cause by the time your done you'll have arms like popeye.

Have fun!

C.</div></div>
Chad,

Thanks for this! The receiver is simple in design and looks to be a round piece of pipe in crude terms. I'll measure it to make sure, but if it is in fact perfectly round as I think it is, would a dowel or even a curved piece of sheet metal (I can do that in-shop too if need be) suffice in place of the action? I cannot bring the rifle itself into the shop. So if this is the way I decide to go, I'll need a substitute for the receiver.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Outsy</div><div class="ubbcode-body">How much material are you looking to remove?

Why not get some sacrificial screws the same size as the receiver holes and cut the heads off simply to make some alignment rods. lube em up good and build a dam around the area with some modeling clay, lube the receiver and lay down some JB and then set the rail into the JB with the screws in the receiver thru the rail.

I know its not the best way, and I am sure looked at like the bubba way, by actual smiths but hell it would work. </div></div>
Outsy,

I believe that the receiver is 1" in diameter, so a fair bit of material on that. Then on the blank pic-rail there is a good amount of unneeded material too, but that doesn't exactly need anything special. I just need to keep it flat to mount to the "lower-rail" if that makes any sense.

I thought about using JB Weld but I don't think it would turn out all that well. I may be completely wrong in that statement, so I may end up giving it a trial run anyways on some scrap metal. I do think that regardless of the amount of work involved, that I would rather have shaped the metal to fit at least close and then finish off with bedding compound for a perfect fit over creating the curve with JB and calling it good. Like I said, I'll probably give it a shot anyways sometime
wink.gif




-Dylan
 
Re: Need help with DIY project

Buy a set of 2 piece Weaver bases to fit your receiver.
Cut them down to the thickness you want and then screw/glue your pic rail to the top of them.
 
Re: Need help with DIY project

That doesn't accomplish the overall goal of being able to mount the match sights directly to the base...
 
Re: Need help with DIY project

Don't think it will work. You have to be sure that you are creating the radius parallel to and centered between each side of the rail. Doing that by hand is, unless your a truly talented tool and instrument maker, darned near impossible. Not to mention that maintaining a constant radius throughout the entire length of the rail would be problematic within itself.

One of the reasons precision stuff costs so much.

Quick fix. Take it to a machine shop that has a larger surface grinder. They can dress a profile on the grinding wheel which will give you your desired radius. They will indicate the piece in on the surface grinder to bring it to center and then procede to generate the required modification.
 
Re: Need help with DIY project

I would measure the radius of the receiver and get a drum sanding tool with the same radius and go for it. Start with 36 grit and rough it out and then finish with 220 grit. I cant imagine that the aluminum alloy that they use for those rails is all that hard.
 
Re: Need help with DIY project

terror, would a regular pic base for a 40x work if you had some one mill off the back slots and then flush up the sides stright up? if it's aluminum, you can even file it down yourself.

the side can then be drilled an tapped, and an aluminum or steel spacer (sort of like a LOP shim on a buttstock) can be added to get the aperature somwhat centered / or to where the frame of the sight would be on the same plane to where it would usually be mounted on the receiver. then the spacer can be attached to the base.

then the spacer can be drilled and tapped to accept the sight.

seems like a lot of work, but trying to sand the bottom of a blank down will be too, not to mention chances of getting perfect are goin to be next to impossible. but if you go with the blank, instead of trying to sand it round, get it milled in a "V".

the two outer edges will stradle the receiver. it'll be less contact, but should at least be straight.

just a couple of thoughts.
 
Re: Need help with DIY project

If you or a buddy have a mill its a lot easier-

The formula is SINE A = R/DR
A is the angle of the milling machine head
R is the radius of the end mill
DR is the desired radius to be cut.

For my purpose I used a 3/4 end mill,the diameter of the receiver tube is 1 3/8 diameter and the angle I needed to set the head was 33.055 Deg.

This was for a blank piece of weaver rail to fit the radius on my SMG receiver.

I made an excel workbook with the above formula.Instead of doing the math long hand I simply plug the diameter I need in with the diameter of the end mill I am using and it outputs the correct angle to offset the milling machine head. If anyone wants the excel sheet email me and I will send it to you.

radiusmilling.JPG


cutter.JPG


rail.JPG