Gunsmithing Guard Screw Collet porn

[LRI]

Fitting guard screws is a deceptively simple process. While some are satisfied with blasting a screw against a grinding wheel or belt sander, others look for an alternative.

I've made a collet setup that captivates the body of the screw without mashing the threads or having to slide the screw from the rear of a 1/4" 5C collet. This is the latest revision as the previous version had a portion of the O ring exposed above the body that always caught on the inside of the 1" collet.

Tools like this really go a long way towards making stupid jobs quick/dirty and clean. Screw leads are square to the body and the thread chamfer can be easily restored so that the end user doesn't have fits putting his rifle together.

I like using a boring bar to trim these screws. Running the spindle in reverse puts the cutter on the backside so that in one setup I can face the screw and chamfer. If you choose to do it this way, just make sure your tool's on center and your don't go too far past spindle center. The little boring bar inserts I'm using won't tolerate it well. They'll chip at the lead edge of the cutting surface if you mistakenly load them the wrong way. At $47 bucks a piece you can hemorrhage the VISA card pretty quick if your not careful.

Maybe it'll help out a guy down the road somewhere.

Enjoy.

C.

 

[LoanHarvey]

That looks like what I need. I bought 2 action screws for a Rem700 from BAT and they arrived and are both too long, so they just set in the bag they came in. I wanted to replace the old straight slot screws.

 

[LRI]

Time permitting, maybe I'll whip a bunch up and have a little GB action...

 

[BillyGoatMachine]

Time permitting, maybe I'll whip a bunch up and have a little GB action...

I'm in.

 

[Red_SC]

That's a good idea, I chipped an insert last week on a guard screw.

 

[Gene Poole]

Guard screws chuck up nicely in a 3/8 or 1/2 Jacobs chuck too. The allen head fits behind the jaws nicely. It takes a non-trivial amount of time for me to set up the 5C drawbar and closer, but I only have to remove the chuck to pop in a Jacobs on a MT3 mandrel (plus the South Bend adapter). True about munging up the threads if you clamp that Jacobs too tight though.

 

[LRI]

This'll work in a 3 jaw as well.

 

[NXS338]

Is the inside of this collet threaded? This is a really cool tool.

 

[MarinePMI]

And here I was, using split nuts to hold screws into a 3 jaw chuck...

Seriously, nice set up!

Out of curiosity, do you have something akin to a case shoulder gauge to set up the depth of the screw into the collet? Seems like that'd be a really quick & fairly precise way to set up the depth, with the flange (of the work piece collet) pressed into the collet in the head stock...

 

[Jkob60]

I make it simple; i take a piece of aluminum round stock, drill a hole through it the size of the screw and split it. It goes in the three jaw and I use a parting tool to shorten it. Five minute job or less.

 

[Edds]

An automotive valve grinder, the side that is used for facing and chamfering the valve stems, works well for trimming and chamfering bolts. They aren't expensive compared to the stuff you guys use. I sold my well used one about 10 years ago for $450.

 

[LRI]

And here I was, using split nuts to hold screws into a 3 jaw chuck...

Seriously, nice set up!

Out of curiosity, do you have something akin to a case shoulder gauge to set up the depth of the screw into the collet? Seems like that'd be a really quick & fairly precise way to set up the depth, with the flange (of the work piece collet) pressed into the collet in the head stock...

I do it like this:

Run the screw in the gun to assemble it. Attempt to close the bolt. Back the screw out and count the rotations till the bolt drops. Go an extra 1/2 rev from that. Take the # of rotations X's the pitch and that's how much you trim. A 28 pitch is .0357"

Same for the rear.

On blind holes I just chip away will I get it.

Whole point of this tool for us is that I have a tool room lathe (Hardinge) that's never had a scroll chuck on it. So, swapping a collet and using this is quick work. If your stuck with one lathe, this may/may not be the best solution for you although I used a 3 jaw for years to do this stuff.

Aluminum will certainly work, but this is a tool I only wanted to make once. So, it's out of O-1. This way I don't ever have to worry about cross contamination of aluminum/steel when bluing parts. (AL bad ju ju for salts)

C.

 

[Clark]

When modifying 10-32 attachment screws for the co-ax press shell holder jaw housing for faster centering during jaw end swapping, I did not have a collet. So I screwed them into a threaded hole in some hex steel and ran the lathe backwards so they would not unscrew while cutting.

 

[cav has been]

Thanks Gentlemen! Great ideas for those of us that are creatively challenged. Beautiful work as always Chad, thanks for sharing and inspiring!

 

[LRI]

FWIW:

To me, this is REAL gunsmithing. The little tools and nippitz that can get a guy profitable. Be nice if there was a section here that was sticky'd for those in the trade willing to show different ideas for work holding and processes that go into the detail needed for a guy to really do something. Not just a grainy cell phone pic and two lines of text.

The knowledge pool can always go deeper IMHO. Last week I built a kick ass fixture for inletting the ejection port and bolt handle feature using the 4th axis as the work holding. Now I can use the side of the tool to generate the SFM needed to cut composites cleanly. Before I was surfing it out with a ball and it left little lines that drove me nuts. I can also do a bolt handle inlet like nobodies business because I can rotate the stock to the appropriate angle. Theres a surprising amount of complex geometry in that little feature when you really "go for it" to make it a mirror image impression in a stock.

It's a worthless fixture unless you have a machining center, but stuff like that might help a guy out later in life.

Time bring this trade out of the dark ages!~

C.

 

[300sniper]

Time bring this trade out of the dark ages!~

C.

Ayup!

 

[mcfred]

Running the spindle in reverse puts the cutter on the backside...

Out of curiosity, does it matter which direction you spin it? Is it just because your compound is already angled this way? With the threads clamped (I'm assuming the collet is threaded?), you should be able to spin either direction and not worry about the screw threading itself in or out.

Thanks for posting this up; I totally agree about getting out of the dark ages!

 

[LRI]

Has nothing to do with screwing in/out. Has to do with cutter geometry. Tool edge dictates reverse on the spindle for my setup. Collett isn't threaded. This way any 1/4 screw fits.

 

[MarinePMI]

FWIW:

To me, this is REAL gunsmithing. The little tools and nippitz that can get a guy profitable. Be nice if there was a section here that was sticky'd for those in the trade willing to show different ideas for work holding and processes that go into the detail needed for a guy to really do something.

It would be nice to see a "Gunsmithing Fixtures & Gadgets" section. I doubt my amateur skills would contribute much (if at all), but it would make a nice addition (IMHO). Reminds me of an M-1 Garand jig I saw once for heating/bending the op rods for the tanker versions, or the jig for making an obsolete trigger on a wheel gun. Kind of an online version of "Gunsmith Kinks", but in a forum... (great books BTW for stuff like this topic)