Disaster averted - 4506 RailGun

[BMCM]

Ahoy there Gents,

Been a long time eh? Yeah yeah I know, Been pretty darned busy of late.

Anyhow this came my way and I thought to share the fix...

Story begins with the owner asking me about sticking a factory TSW rail on a 4506. Well sez I... "that TSW rail is a aluminum piece of rubbish, get you a Novak bolt on rail. The Novak has the right contour to fit the dustcover and is a proper picatinny rail that will accept any pic-rail gizmo without need for a silly adapter thingy"

A few days later I receive a distress signal with a couple pics...

Owner marked and center punched the spots to drill and on the first hole the drill bit wandered way off center

Oh we kinda double punched that front hole too

Yeah, that's no good at all

A few days later it's here on the healing bench for sorting out.
First order of business is the get the rail section properly leveled and clamped to the frame so I can mark it for machining.

Splash on some dykem fluid...

Then get the rail level to the frame and securely clamped...

With a carbide scribe, mark each hole. Now we have a much clearer view of how far off things were...

Now to the fix.

The key here is anytime you want to drill a hole in a round surface like a rod or bar or pipe or mmmm dustcover, you must first create a flat spot.

Why is that you may ask? Well because when you start turning the drill bit it will tend to take a bigger bite of the steel on the long axis of the part or on the high spots. Even with a perfect grind on the bit it will still tend to walk off to one side or the other as seen here. So what we do first is head over to the mill and make some flat spots.

Making a flat area the same diameter of the hole you want to make eliminates the high spots that will cause your drill to wander

Set up on the mill table in the vise. 1/8" carbide end mill in the quill. We create a 1/8" diameter flat for each hole. I'm just lining up the cutter eye here, one more to go. Don't have to go very deep at all just enough to make a flat the full diameter of the cutter .020 - .030 or so...

Swap out the cutter for a #2 spotting bit and poke a starter for the first hole...

Like so...

Then we swap to a #29 cobalt jobber drill which is the correct drill size for a 8-32 thread and drill clear through...

Then we swap out the drill for a 8-32 tap. I rigged up motor reversing switch on the mill so I can power tap right on the machine without moving anything...

First hole done and back to the bench. Stick in the first fastener, removed the clamp and verify level & alignment before we head back to the mill to complete the remaining holes...

All three done...

But now we need to trim the screws to length...

The screws are hardened alloy steel. I considered several methods of cutting these screws and in the end settled on using a rotary tool & cutoff wheel while holding the screw in a pin vise...

All three cut to length, still a little more cleanup needed on the mini belt grinder and a touch of oxpho-blue...

Getting ready for final install. Rail coated with Loctite 620 retaining compound. That will act as bedding compound of sorts and seal the joint to prevent any moisture or fluid wicking in there and causing corrosion...

For the screws, swab out each hole in turn and coat the screw with Loctite 272 high strength high heat threadlocker...

Allow ample time for all the goop to cure...

Then cleanup any excess...

And... Done!

The fully assembled "RailGun" is all packed up to ship out tomorrow heading home.

I'll leave it to the owner to post pics of his new er remodeled toy assuming he chooses to do so

If nothing else remember the key takeaway when drilling into something round or convex... make a flat spot first

Cheers
Bill

 

[Sevens]

I loathe rails on handguns, but this isn’t -my- handgun and I understand that my tastes are my own. As expected, the tutorial is phenomenal!

 

[mikerjf]

I understand the concept behind the flats... but with the work clamped and starting with a center drill, possibly even in a punch mark, is it usually a problem?

Your method of finishing one hole and then screwing the piece on to help align the next is something I've been doing on guitars from day one.

Just remembered something else I do... I make my first centerpunch pretty light, so if it proves to be off I can "move" it the right way with a heavier hit... LOL, makes me sound pretty bubba, I guess.

 

[kobsw]

Outstanding!!! I've said it before and I'll say it again, you're a true Craftsman... You've enriched this forum once again.

Best Regards,

Kobsw

 

[Jeppo]

Your work is absolutely amazing. I can barely insert the key in my front door without breaking it.

 

[03hemi]

You did an amazing job!
The guy wanting to put a rail on that collectable 4506 should be slapped and drug behind a horse in the dead of winter, horrible and stupid decision!
Here's an idea, buy a cheap plastic gun that has a rail already?
Some people.

 

[Jim Watson]

Interesting.
I wonder how much trouble it would be to mung one up for my Sig Sauer P226. Have to compare frame radius.

 

[Erocksmash]

Once again MR. BMCM has saved my rear and created a masterpiece, some may not like the rail, but that said, "not your gun"...

I'm so excited to get ol girl back and put her back to work around the ranch..

I'll post about her when she comes home, got some other bits to add about the gun and it's holster system




Sincerely Thanks Bill !!!!

 

[WR Moore]

I once saw a tap holder with a tail at the handle end. The idea was that once a hole had been drilled, the tap could be aligned with the drill chuck in the mill/drill press and kept straight while you ran the tap by hand. Like an idiot, I didn't buy one and haven't seen one since.

 

[cherrypointmarine]

Bill , I was expecting something like my 745 that you brought back to life . As usual you showed all of us why you're the go to guy here when we have problems .
On a side note .... wouldn't it have been easier if he would have drilled a pilot hole first ? Like a #30 or #40 ? That's what we used to do . If we were drilling by hand , always drill a pilot hole , then work your way up .

 

[Doug M.]

BLUF: Some people can do their own gunsmithing. The rest of us mortals should simply pack up the project and a check and send it to Bill.

 

[ElectroMotive]

An excellent idea for someone who wants to mount a weaponlight on a 3rd Gen.

Is it doable for a 5906?

 

[GaryS]

Beautiful work as always. The tutorial and photos are always informative.

"Never drill on a round surface" is great advice. I'll keep it in mind for the next time I have to drill a tube, pipe, or dowel.

 

[BMCM]

I understand the concept behind the flats... but with the work clamped and starting with a center drill, possibly even in a punch mark, is it usually a problem?

Your method of finishing one hole and then screwing the piece on to help align the next is something I've been doing on guitars from day one.

Just remembered something else I do... I make my first centerpunch pretty light, so if it proves to be off I can "move" it the right way with a heavier hit... LOL, makes me sound pretty bubba, I guess.

Drilling into a flat you can get away with nothing more than a center punch to spot the bit because your going to raise a uniform chip as the bit turns. But you want to make a punch mark that is at least as wide as the chisel point on your drill bit else the bit will likely walk off the mark as if there was no punch mark at all.

On a round however like our dust cover here, the bit would only lift a chip when the cutting edge aligns with the center-line instead of raising a continuous chip. The bit is cutting in pulses and each time it takes a bite it can push or wander off the mark. This is especially a problem if drilling by hand as the least bit of tilt off perpendicular will make the bit walk. And then, even if the setup is very rigid as on a mill or drill press with the workpiece securely clamped, the bit can still flex and move off the mark. So, we machine a flat then start the hole with a spotting drill which is very short and rigid.

Cheers
Bill

 

[BMCM]

I loathe rails on handguns, but this isn’t -my- handgun and I understand that my tastes are my own. As expected, the tutorial is phenomenal!

Me too. I am often dismayed with current production handguns. Seems every damn one of them from every maker has a bloody pic rail on it. Even little tiny pocket guns presumably intended for discrete concealed carry have that cursed rail. I can see the utility in some respects, it's just not my thing.

Often I see something new that I kinda like but nope it's got that bloody rail on it... pass

Cheers
Bill

 

[18DAI]

Masterful work, one again. Not something I would want to do to one of my 4506s, but thats why there is chocolate AND vanilla.

Thanks for taking us along BMCM. As always, an interesting thread and I learned a bunch! Regards 18DAI

 

[BMCM]

You did an amazing job!
The guy wanting to put a rail on that collectable 4506 should be slapped and drug behind a horse in the dead of winter, horrible and stupid decision!
Here's an idea, buy a cheap plastic gun that has a rail already?
Some people.

Thanks for the compliment

Now Now, lets be civil. Don't you think that punishment is a tad bit extreme. I've done quite a bit of 'customizing' to my personal guns that one could argue ruins their collectible value. I don't care.

Consider that perhaps your "cheap plastic gun that has a rail already" is exactly why this mod was wanted. A laser aiming module affixed to a droopy noodley limp plastic rail... Nope, no good at all

Cheers
Bill

 

[03hemi]

Thanks for the compliment

Now Now, lets be civil. Don't you think that punishment is a tad bit extreme. I've done quite a bit of 'customizing' to my personal guns that one could argue ruins their collectible value. I don't care.

Consider that perhaps your "cheap plastic gun that has a rail already" is exactly why this mod was wanted. A laser aiming module affixed to a droopy noodley limp plastic rail... Nope, no good at all

Cheers
Bill

Sorry for that, I hadn't taken my meds yet.
Gorgeous job too though!

 

[BMCM]

I once saw a tap holder with a tail at the handle end. The idea was that once a hole had been drilled, the tap could be aligned with the drill chuck in the mill/drill press and kept straight while you ran the tap by hand. Like an idiot, I didn't buy one and haven't seen one since.

If you look at any T handle tap wrench it will have a 60° center pocket cut in the top...

That's to accept the pointy end of this tool, a spring loaded tap guide...

Once your hole is drilled to size, stick that tap guide in your drillpress chuck and use that to locate you tap which is held in the tap wrench concentric to the hole. It is spring loaded to exert some down pressure as you turn the handle on the tap wrench by hand...

Cheers
Bill

 

[Protocall_Design]

A lot of people don't know that those tap guides usually have a tapered hole on the other end that goes on the top of the tap if you're using a straight tap handle. You unscrew the black cap from the body and turn the pointy end around for that.

Most times, the smaller taps are broken from sideways pressure on the tap by turning it freehand. The tap guide can prevent a lot of broken taps and ensures that the hole is exactly straight.