September 23, 2010
A new magazine latch is needed to make this small pocket pistol serviceable. The latch has broken at the pin hole.
It seems like it was just yesterday rather than more than 35 years ago when my old gunsmithing mentor Sid Cross pounded the following pearl of wisdom into my admittedly young and empty head. He said, "Don't ever make a part if you can buy it."
Sid had a darn good point, and for the most part, he was absolutely right. Seldom will you ever come out ahead by making almost any part you can buy. This is certainly true for parts for modern guns still in production as well as for many older, discontinued guns.
Still, Sid wasn't always right, bless his soul. For example, not too long ago, a young woman brought me a Sterling .22 rimfire pistol. The magazine latch was broken at the pin-pivot hole and would no longer hold the magazine in place.
Coffield starts with a piece of mild steel that's fairly close to the same thickness as the broken part, but there's still a lot of steel to be removed.
Although Sterling went out of business in the 1980s, many parts are still available. In fact, Numrich Gun Parts offers the magazine latch for just $7.50. Realistically, there is no way you or I could make a replacement magazine latch for that amount. On the face of it, Sid was right. Except, there are times when you need to turn a project around very quickly. In those cases, the price of an available part is not as important as time.
Small handguns like this are neither target guns nor recreational plinkers. They basically have one and only one function: personal protection. As this was the owner's primary use--questionable effectiveness of the .22 rimfire aside--the gun needed to be returned to the owner quickly, and there simply was no time to order a part.
For those who have a pretty low opinion of handguns like this and think I should simply have insisted the owner buy a better handgun, I can only say, my friends, you are living in a different world than I. Not everyone can afford a Glock or a Smith & Wesson or a Beretta. A lot of good folks have what they have, that's all they have, and that's all they're gonna have. You either help 'em or you don't, and I chose to help the young lady. And frankly, if you'd been in my place and had talked with her, I bet you would've done the same thing.
Making a part like this doesn't have to take a lot of time. There are steps you can take to make the process faster and easier. Also, when you make a part, you can sometimes redesign it to actually make it better. You don't always need to be a trained engineer in a firearms plant to recognize when a part can be improved.
With the broken part firmly clamped in place on the Dykem-covered steel flat, Coffield traces around it with a sharp scribe. Note the mark for the pivot-pin hole that was made with a transfer punch.
Reid advises not to use a file when there's enough material to use a hacksaw.
That's just the case with this magazine latch. I'd noticed on other similar model Sterlings that the magazine latch extended out into the magazine well a bit too far. In fact, it made inserting a magazine difficult. This was something I wanted to correct as I worked on the new part.
One of the biggest mistakes folks often make is that they start with a piece of steel that's far too big. All this does is add time and effort to produce the needed part. After all, you have to cut away all that extra metal. I learned long ago to never use a larger piece of steel than is absolutely necessary. In fact, I make sure the metal stock I use comes very close to matching at least one dimension of the part. In this case, I used a piece of mild steel that was about 1/4 inch thick. That closely corresponded to the original part, which was .223 inch thick. I only needed to remove about .027 inch to have a perfect match.
The vise jaws are used as a guide and a stop when filing. The magazine latch has been cut out and filed down to near final dimensions. Now, only minor shaping of the latch head and fitting to the pistol need to be done.
Next, if at all possible, use the original part as a pattern. After cutting off a section of my quarter-inch-thick mild steel flat, I coated the surface with Dykem machinist layout fluid, allowed it to dry, laid the old part on the Dykem-coated surface, and traced around it with a sharp scribe. When tracing, be careful that you don't duplicate the broken portion of the part. Also, if you're planning on modifying the part or changing it, allow for this as you make your tracing.
To make installation of the magazine easier when performing the final fitting, use the magazine to position the latch. The seat for the latch spring is a blind hole located on the back of the magazine latch. Grooves on the magazine latch are cut with a No. 1 checkering file that provides 32 lines per inch.
If you're able to work with a broken part, while you have it held in place, use a scribe or, better yet, transfer punches to locate any pin or screw holes. Transfer punches are ideal for this task, and every gunsmith ought to have a set.
In the event you don't have a broken part to use as a pattern or your part has a primary pin or screw hole, it's often helpful to mark the location of the hole first. After locating this hole, you can then use it as the c
entral point from which to determine all other dimensions. Using a primary hole as your main index point helps to prevent making a part and then ruining it by putting a hole in the wrong location. Sometimes having a pin or screw hole off by just a few thousandths is more than enough to ruin a newly made part, and, yes, I've done it. Again, if possible, make the primary hole first.
With the part drawn out on the flat steel stock, the next step is to remove the excess steel. For some reason most folks think that you have to use files for this. That's fine when you have just a small amount of metal to remove, but when you need to remove more, a file can take forever. If you have to remove more than 1/16 inch of metal, use a hacksaw. Rather than file away the material, cut it off with the hacksaw. Yes, you do have to be careful, but judicious use of a hacksaw can literally save hours of work.
A bit of steel must be removed here to allow the latch to pivot back far enough to release the magazine. The hook on the latch that engages the magazine body also requires fitting.
The repair is completed in just a little more than an hour, and the pistol is ready to be returned to the owner. Coffield uses cold blue to apply a finish to the new part.