Gunsmithing dbm bottom metal drawings

[Sidk]

I bought me a mill a while back and have been learning to use and have even made some small parts. Having a blast. I'm in need of a dbm bottom metal for a R700 SA. I'm doing it by hand, no cnc on this mill till after the lathe purchase and then this one is going cnc. I have the material and the time to make it myself but I sure could use some drawings.

Anyone have something drawn up they wouldn't mind sharing? Oh yeah, AICS type mags.

TIA

 

[cap2031]

Re: dbm bottom metal drawings

I'm going to guess you might not get a lot of traction on this one. Everyone who has a DBM is holding that design (prints) in their intellectual property vault.

Best thing to do is order one (check out PTG). Then get the critical dimensions and from there design your own style and lines.

Looking forward to seeing what you come up with. I think there is a market for low cost DBM's that are rigid.

 

[Sidk]

Re: dbm bottom metal drawings

Thanks but I already have one. I didn't want to take the rifle apart to measure it. I was hoping someone could give me the basic specs.

Well lets forget the specs. But could I ask when milling this piece should I start up right or on its side? I figured I would do the bottom mag well last so I could keep the piece sqaured in the vice till the very end the flip it over and clamp it in its trigger guard and mill the angle. What do you think?

 

[bohem]

Re: dbm bottom metal drawings

I would cut the magwell first actually and then put a block inside it to provide support when clamping into the work fixtures.

The reason being that extruded AL is notorious for changing shape when you blow out the middle of it. I found out the hard way when I made a differential carrier for a race car. I nailed all the OD bearing surfaces perfectly. Contoured the inside and nailed them. This thing took me the better part of a week to cut on a manual lathe.

When I went to assemble the OD bearing races were between 0.002 adn 0.005" undersize. The internal stresses of the material were relieved when the ID material was removed. I was baffled and pissed at myself and couldn't figure out what happened so I called a friend/mentor and he just started laughing. When he stopped he said "welcome to the club, you're officially part of the DAMMIT! group" and explained what happened.

 

[romanleader]

Re: dbm bottom metal drawings

Machine the outside dimensions first, length, width, and trigger guard o.d. Next rough out the t-guard and magwell, leaving stock for finish. Make a block to support the magwell for clamping, follow on ops, etc. Finish up with holes, and cleanup and coating.

Good luck!

 

[Sidk]

Re: dbm bottom metal drawings

Thanks guys. I've got most of it drawn out. Chad posted the inlet for a stiller metal and tossed about a 1/3 of the specs so that made it much easier.

Now the mag well is angled. Would you cut the main flat part where it bolts to the action first then do the angle on the mag well(length wise)? Seems that it would be easier to the use ends mic'ed up as to set the angle for the well. Thinking I can use the steps of one of my clamping blocks to set that angle after that first cut. Probably over thinking it but I don't want to trash a $40.00 chunk of aluminum.

 

[bohem]

Re: dbm bottom metal drawings

RL, that's good advice. I was hesitant on doing 2 cuts for the outside net shape as I assumed (perhaps incorrectly) this was going to be done on a manual mill. Personal preference, I hate having to go back and make finishing passes after breaking down a setup.

OP, good luck with it. I'd cut the flat portions first and use them as the indicating surface for the angle since the flat portion is what will be the reference surface when the DBM is in the stock.

 

[Sidk]

Re: dbm bottom metal drawings

Yup its a manual mill. Probably going to cnc it later after I buy a lathe.

 

[Keith Johns]

Re: dbm bottom metal drawings

When I made my 10/22 receiver it warped like a Mutha.

I had to rough in cuts, not going to finish dimension until later on in the process. I let it warp, and left enough material there to "fix" it after it warped.


If I had gone to finished dimension on most of the operations, it would've been screwed up.

Solid block:

Roughed:

Little more removed:

Damn near done:

Done:

Almost every step it warped a little, and had to be set up and surface ground back into parallel and square... before putting it back into the mill to keep going.
Everything going off the receiver face.


Good luck with the project. Post pictures.

 

[MikeeBooshay]

Re: dbm bottom metal drawings

A lot of good advice here.

If I was going to ever make more than one of these though, I would spend more time making tooling for it than making the first article. Three or four fixtures would speed things up greatly, and remove or reduce the introduction of setup errors. You can also make a bunch of parts in one setup much easier, to a more consistent quality.

In time, the time spent refining your fixtures, will pay off in both quality and speed.

 

[Sidk]

Re: dbm bottom metal drawings

Excellent Keith. I was thinking about making my daughter a lefty 10/22 like that. Nice work. Yeah, I'm roughing it out leaving about .200 for the first pass. Thanks for the advice.

I agree with you Mike, I would be making some tooling if I was going to make a bunch, or, I'm building a forge now too so I could just cast them..

 

[marksmatter]

Re: dbm bottom metal drawings

Holy crap, Keith - that is cool!

 

[Keith Johns]

Re: dbm bottom metal drawings

Thanks.

You can make one on a decent manuel mill. Coolest thing I ever made. Make a 10/22 instead and just buy a Badger DBM

The places like Badger, Surgeon, Seekins, etc. that turn out bottom metals, I wonder if they deal with warping... or if it's possible to buy more expensive aluminum that is totally relieved and wont warp at all.

The 10/22 receiver was just cheap ass steel. It started flat each time, and each operation was enough to make it wiggle when set on a flat granite table top afterwards.

 

[Sidk]

Re: dbm bottom metal drawings

You guys ain't kidding about warping.... Holy crap I'm gonna have to square this thing back up after this first roughing. I had to move the work in the mill vice and now it won't sit square where it did before. I'll get some pics tomorrow and post them. I did a set of bedding pillars for it too.

 

[Sidk]

Re: dbm bottom metal drawings

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">Thanks.

You can make one on a decent manuel mill. Coolest thing I ever made. Make a 10/22 instead and just buy a Badger DBM

The places like Badger, Surgeon, Seekins, etc. that turn out bottom metals, I wonder if they deal with warping... or if it's possible to buy more expensive aluminum that is totally relieved and wont warp at all.

The 10/22 receiver was just cheap ass steel. It started flat each time, and each operation was enough to make it wiggle when set on a flat granite table top afterwards. </div></div>

Naw, gotta build it, Besides I've already started. The trigger guard part of the piece is going to be the hardest part. Haven't figured out machine the curves. I've got to get a rotary table. I'm sure that would help some.

 

[Keith Johns]

Re: dbm bottom metal drawings

Could design a two piece bottom metal to make machining easier.
Dovetail and set screw maybe

 

[romanleader]

Re: dbm bottom metal drawings

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sin City Shooter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">Thanks.

You can make one on a decent manuel mill. Coolest thing I ever made. Make a 10/22 instead and just buy a Badger DBM

The places like Badger, Surgeon, Seekins, etc. that turn out bottom metals, I wonder if they deal with warping... or if it's possible to buy more expensive aluminum that is totally relieved and wont warp at all.

The 10/22 receiver was just cheap ass steel. It started flat each time, and each operation was enough to make it wiggle when set on a flat granite table top afterwards. </div></div>

Naw, gotta build it, Besides I've already started. The trigger guard part of the piece is going to be the hardest part. Haven't figured out machine the curves. I've got to get a rotary table. I'm sure that would help some. </div></div>



If you have a boring bar/head, try that, step it out a little at a time. I would for sure make this out of steel, personally, use the Al as a trial piece.

Keith, damn fine work bud!

 

[Sidk]

Re: dbm bottom metal drawings

Hmmm a boring bar. I think an end mill would work better because the guard is slotted. But I'll take any info you veterans of the mill want to give me. I've got it mostly shaped but the weather been crappy and I've had other hunny-do's but I do want to get it finished up this weekend.

 

[Keith Johns]

Re: dbm bottom metal drawings

If it comes out nice post a pic. My buddy is interested in doing one where he took CNC classes.

 

[Sidk]

Re: dbm bottom metal drawings

The Motor on my new Grizzly mill blew the cooling impeller apart so I'm waiting on a replacement, but sure, I'll post a pic when its done. I suppose I could post some of the work already done. I'll see what I can do when I get home later. Hopefully the motor will be here tonight.

 

[Sidk]

Re: dbm bottom metal drawings

Well the mill is back up and running. Here's where I'm at with it. A little bit more roughing is needed. I bought some better end mills, amazing how much faster you can cut. Now I see why those guys put the 6800 rpm motor on these mills. Grabbed a rotary table, 5x7 swivel table, roughing end mills and a few other things while I was waiting on the mill part.

All in all its a lot of fun.

 

[sawman556]

Re: dbm bottom metal drawings

Cool!!! Get to work so we can see it finished.

 

[Sidk]

Re: dbm bottom metal drawings

I've got quite a bit done this weekend looking pretty good. I didn't get any pics tonight, but tomorrow night for sure. Today was taking the final measurements and making those tight corners for the mag well.

 

[2156SMK]

Re: dbm bottom metal drawings

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sin City Shooter</div><div class="ubbcode-body">making those tight corners for the mag well. </div></div>

Grind yourself a broach from an old broken endmill.
Use the mill to work your way into the corner with it.
Step over a thousandth, make a stroke.
It's slow, but it gets the job done...

 

[Sidk]

Re: dbm bottom metal drawings

I used a .125 drill bit as the corners of the one I'm using as a template had radius on the corners. Coming along pretty good. Sure is a lot of work but I enjoy it. I would rather make the parts if I could as to buy them. That was the whole reason I bought the mill and I'm getting a 12x36 lathe soon.

 

[Sidk]

Re: dbm bottom metal drawings

Thought I would post some progress pics. Yes, I'm super slow. I actually quit working on it as I was going through some medication changes and I didn't want to take a chance on hurting myself while adjusting to the meds.

Getting close to being done. Maybe a week or less. I'm going to order a CDI for my la Savage. Then I'll have that one too.

I definitely need a better selection of endmills. I probably won't make anymore of these till I make some gigs. It seems like I spend half my time doing setups with the di

Think I'm going to order the cnc kit for my mill.

 

[LRI]

Re: dbm bottom metal drawings

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sin City Shooter</div><div class="ubbcode-body">I bought me a mill a while back and have been learning to use and have even made some small parts. Having a blast. I'm in need of a dbm bottom metal for a R700 SA. I'm doing it by hand, no cnc on this mill till after the lathe purchase and then this one is going cnc. I have the material and the time to make it myself but I sure could use some drawings.

Anyone have something drawn up they wouldn't mind sharing? Oh yeah, AICS type mags.


It's easy:

1. Get your center to center hole spacing sorted out for the action your using. Measure inside to inside and add the ID to that value.

2. Pick one hole to be zero. I always use the rear one.

3. Measure from the hole center to the rear of the magazine mortise.

4. Measure from the hole center to the front of the magazine mortise.

This defines the "box" that you have to work within. Dimension your magazine well within this containment. Add .01" to those dimensions for clearance so that magazine fits in/out without a mallet.

5. Build the frame and ignore the mag release for the moment. Get it looking right so that it'd fit in the stock and essentially operate.

Now set your magazine in your action, slide the part over it and determine where the magazine release needs to be. Make it long so that once you fit the part in the stock you can trim it till it provides ample case purchase on the bolt face while not crashing the feed lips into the bolt body.

That's it. Your done.

The pretty stuff is left to artist interpretation.

Good luck and bravo for taking this on. Few things are as rewarding as making your own gun parts from scratch.

C.

TIA </div></div>

 

[Sidk]

Re: dbm bottom metal drawings

The latest updates, almost done, drill some holes and make the magazine release lever and corresponding grooves and pin holes. I did just hold the mag in and it cycled every round perfectly. There is just a tiny bit of fitment yet to do but its soooo close.

 

[Sidk]

Re: dbm bottom metal drawings

Just need the proper spring, retaining pin and some paint and its done. On to another project.