Building A 1911 - Part II
By Mike Watkins
The last article covered the items
you would need
to build your 1911-type pistol. If you want a refresher or
didn’t
get a chance to read the article simply go to Part
I. This article will cover fitting the slide and frame of your
1911-type
pistol.
| If you have a
slide or frame that is oversize on the rails, you will have to mill or
file down the rails so the slide will go on the frame. If they will
already go together, you may have purchased a pre-fit slide and
frame assembly, so the fit is probably ok. If the components fit
together and have a lot of play you may want to tighten the slide
and rails on the frame. We will cover both procedures
here. |
 |
The first step with an oversize
slide and frame is to measure the width and height of the rails and
grooves on the slide and frame. Write down your measurements,
as you will need to refer to them as you proceed. It is easier if you
will make a rough drawing of the rails from an end view of the
frame and slide. This will allow you to reference the measurements
you have made and visually see how they fit together and where
material will have to be removed so the slide will go on the frame.
Metal may have to be removed from all surfaces or only
one.
Use a Slide/Frame
Rail File. This file has safe edges and cutting edges on it
so you can remove metal only from the surface that requires it.
Proceed slowly and check your progress often. File evenly and
square to the surface you are working on, you only want to
remove enough metal to allow the slide to start on the frame,
although it should be a little too tight.
| Be sure you clean
both frame and slide of all file chips and lube the rails with oil
before installing the slide on the frame. This will help prevent
galling and sticking the slide on the frame. Tapping the slide on
and off with a soft faced hammer will help here. Don’t try to go
too far or you will stick the slide to the frame and could damage
them. This is not the time for a bigger hammer. |
 |
Once the slide will go on the
frame, slowly continue filing and fitting until you can tap the slide
to the rearmost of its travel on the frame. It should not go on hard
or bind during its travel, but should be a little tight. This is strictly a
hand feel or calibrated eyeball condition that you will have to
determine.
Now that the slide will go the frame, lapping them to their
final fit
is next. I use Aluminum
Oxide Lapping Compounds, that has 600 and 800 grit
compounds in one kit. Start with 600 and finish with the 800 grit,
of course. What you want to achieve here is the slide to move
freely throughout its travel, smoothly and without any binding. Go
slowly and check often, you can lap them so they are too loose. If
that happens, you can follow the second part this article to tighten
them back up! No play at all, but free travel is what you are
looking for. You will have around a .001 of an inch clearance with
careful work.
 |
If you have a
Milling machine, the procedure is the same, of course, just easier.
It’s just a motorized file, maybe more accurate discounting human
error. So that’s what it was when I misread the dial!
If you have started with a slide and frame that fits together but
has a lot of play and is going to be a match pistol tightening them
to remove excess play will be needed. Take your measurements
as before. |
On a carry pistol a little play is
acceptable and perhaps preferable, your life or someone else’s
may depend on it. We’re striving for 100% reliability in both!
The method I use is to peen or tap down the frame rails first. You
will want to hold the frame in a sturdy bench vise with padded
jaws and I use a magazine well filler to prevent crushing the
frame. I have been using the Super-Hold
Vise Jaw Pads for years and haven’t torn them
up yet! I took
a piece of Delrin and made a support to go thru the trigger
guard to help
hold the frame in place.
I then slowly tap them down with a 2oz hammer, with a
mirror polished
face. I like the 2 oz. Ballpeen Hammer, Model HP2 (56.7 grams). Don’t tap the rails down
where the magazine
opening is in the frame. The frame will collapse inward and
the magazine
won’t go in until you file it back open or the rails will
crack.
Peen the rails down from about 1 inch from the front of the
front rails
and about _ of an inch forward from the back on the rear part
of the frame.
As you peen down the rails a wire edge will form on the
outside edge of
the rails, this will have to be filed off as you proceed. Here
again trial
fit often and go slow.
Remember the measurements you took, there are hardened
rail spacers you
can use during the peen down procedure. You can get the Brownells
1911 Auto Slide Fitting Bar Set, or they are available
separately,
too. These are held into the groove on the frame as you peen
them down
and control how far to go. They correlate to those
measurements you took.
If you need a .115 inch frame groove to make the slide fit
tight, just
insert the correct spacer and tap away!
| You can tighten
the slide also; we have
the Power
Custom Slide Rail Tool.This is designed to allow you to
SLOWLY tighten the slide by squeezing it so it will fit tighter on the
frame rails. Here again do not try to squeeze the slide in the area
of the ejection port. On the rear of the slide go slowly as the
thumb safety notch is prone to cracking or breaking off. I prefer to
peen down the frame only to tighten them up and leave the slide
alone if I can. That’s probably because I have a Colt Gold Cup slide
in my work bench drawer with a cracked left rear corner. But I
have done a bunch of them. |
 |
You are working for just the
opposite in the Peen down method versus the oversize
component metal removal. But the end result will be the same.
When the slide will just go on the frame a little too tight, and then
follow the lapping procedure for that smooth travel of the slide
without any binding.
Next month we’re on to step #3 – barrel and bushing fitting.
There’s lots more to come and we’ll keep moving until we’ve got a
complete pistol!