How to Enlarge Frame Holes?

[DArBad]

Hello Gang,
I bought an aftermarket hammer pin and a sear pin from Fusion as an aftermarket replacement for my 1911 stock pins. Thought this would just be a drop-in job but I found out the Fusion pins would not fit. The frame hole of the gun is a tad small.

I tried tapping in the new pins without the parts but it got stuck I had to use a punch to tap out. My question is how do you enlarge those frame holes so the new pins would fit??

[mofo1111]

With a drill. Or better yet, get pins that fit, that way you don't ruin your frame.

[compulsivegunbuyer]

You don't drill holes to size, you ream them to size. The point of oversized pins is to fit them with zero axial or radial play. I believe the holes are .110 and .157. The pins should be exactly that size, which makes them a press fit. I would go 2 ten thousandths over for a true precision slip fit. Reamers in .1102 and .1572 are readily available.

[RickD427]

With a drill. Or better yet, get pins that fit, that way you don't ruin your frame.

This gent is half-right. Get pins that fit your frame, don't alter the frame for the pins. DO NOT enlarge a pin hole by drilling

You don't drill holes to size, you ream them to size.

This gent got the other half right.

[tr6guns]

If the pins are too large for frame, what about the grip safety Hammer and sear??

['ol shooter]

The pins are likely made oversize for a frame that the holes are worn and possibly oval-ed so you can ream the hoes round again. take the good advice and don't open the hoels up, return the pins if you can and buy the proper ones. I bought an aftermarket Wilson slide stop a few years back and had to sand the pivot pin a little as it was oversized to compensate for wear which my frame did not have. It's always better to size the pin to the frame if the hole is good, not vice versa.

[saki302]

I would slowly turn the pins down to fit vs modifying the frame. Always work on the cheapest parts.

[ar15barrels]

Hello Gang,
I bought an aftermarket hammer pin and a sear pin from Fusion as an aftermarket replacement for my 1911 stock pins. Thought this would just be a drop-in job but I found out the Fusion pins would not fit. The frame hole of the gun is a tad small.

I tried tapping in the new pins without the parts but it got stuck I had to use a punch to tap out. My question is how do you enlarge those frame holes so the new pins would fit??

I use my sunnen hone to open up holes to fit a specific pin instead of to some standard cutter diameter.
This allows for the best fit possible, far BETTER than the "spec".

A hone is the most controlled method to enlarge holes.
Using a drill or reamer will cut a specific size but using a hone lets you make holes that are more round and are in between commonly available drill bit or reamer sizes.

A hone lets you open up a hole as little as 0.0001" at a time.
Often, a hole just has a burr and it's the burr making a pin tight.
The hone will cut away any burr that happens to be inside the hole without making the hole any bigger.
Or you can keep cutting and make the hole bigger as needed.

[ar15barrels]

You don't drill holes to size, you ream them to size. The point of oversized pins is to fit them with zero axial or radial play. I believe the holes are .110 and .157. The pins should be exactly that size, which makes them a press fit. I would go 2 ten thousandths over for a true precision slip fit. Reamers in .1102 and .1572 are readily available.

I have lots of reamers but a hone will let you go to ANY size you want without having to buy a special sized cutter/reamer.

['ol shooter]

Plus the hone will let you work both holes together so they stay concentric. I used to use one on crank driven diesel oil pump housings to hone the shaft bushings and also on king pin bushings.

[G-forceJunkie]

When you have to fit parts...always modify the cheap part if possable. Why would you modify a $300 frame instead of a 10 cent pin???
Get pins the correct size.
Sand or grind your pins to the size you need.

[compulsivegunbuyer]

I have lots of reamers but a hone will let you go to ANY size you want without having to buy a special sized cutter/reamer.

I have a few adjustable single stroke diamond hones from some past projects I did, not that small, but they were god awful expensive for what they are. How are the Sunnen ones designed? Are they reasonable?

[ar15barrels]

I have a few adjustable single stroke diamond hones from some past projects I did, not that small, but they were god awful expensive for what they are. How are the Sunnen ones designed? Are they reasonable?

The single pass tools are production tools where you need to run hundreds/thousands of parts across them in a production run.
I have all old-school tooling that simply holds a little stone and advances it as you apply pressure.
I have to hone then check, hone then check until i get what I want.
Tooling is still expensive in small sizes because the finished diameter range is 0.005" steps down under 0.3".

K4-A	0.12	0.125
K4-A	0.125	0.13
K4-A	0.13	0.135
K4-A	0.135	0.14
K4-A	0.14	0.145
K4-A	0.145	0.15
K5-A	0.15	0.155
K5-A	0.155	0.16
K5-A	0.16	0.165
K5-A	0.165	0.17
K5-A	0.17	0.175
K5-A	0.175	0.18
K5-A	0.18	0.185
K6-A	0.185	0.19
K6-A	0.19	0.195
K6-A	0.195	0.2
K6-A	0.2	0.205
K6-A	0.205	0.21
K6-A	0.21	0.215
K6-A	0.215	0.22
K6-A	0.22	0.225
K6-A	0.225	0.23
K6-A	0.23	0.235
K6-A	0.235	0.24
K6-A	0.24	0.245
K8-A	0.245	0.25
K8-A	0.25	0.255
K8-A	0.255	0.26
K8-A	0.26	0.265
K8-A	0.265	0.27
K8-A	0.27	0.275
K8-A	0.275	0.28
K8-A	0.28	0.285
K8-A	0.285	0.29
K8-A	0.29	0.295
K8-A	0.295	0.3

[compulsivegunbuyer]

The single pass tools are production tools where you need to run hundreds/thousands of parts across them in a production run.
I have all old-school tooling that simply holds a little stone and advances it as you apply pressure.
I have to hone then check, hone then check until i get what I want.
Tooling is still expensive in small sizes because the finished diameter range is 0.005" steps down under 0.3".

K4-A	0.12	0.125
K4-A	0.125	0.13
K4-A	0.13	0.135
K4-A	0.135	0.14
K4-A	0.14	0.145
K4-A	0.145	0.15
K5-A	0.15	0.155
K5-A	0.155	0.16
K5-A	0.16	0.165
K5-A	0.165	0.17
K5-A	0.17	0.175
K5-A	0.175	0.18
K5-A	0.18	0.185
K6-A	0.185	0.19
K6-A	0.19	0.195
K6-A	0.195	0.2
K6-A	0.2	0.205
K6-A	0.205	0.21
K6-A	0.21	0.215
K6-A	0.215	0.22
K6-A	0.22	0.225
K6-A	0.225	0.23
K6-A	0.23	0.235
K6-A	0.235	0.24
K6-A	0.24	0.245
K8-A	0.245	0.25
K8-A	0.25	0.255
K8-A	0.255	0.26
K8-A	0.26	0.265
K8-A	0.265	0.27
K8-A	0.27	0.275
K8-A	0.275	0.28
K8-A	0.28	0.285
K8-A	0.285	0.29
K8-A	0.29	0.295
K8-A	0.295	0.3

I found some examples. I will have to keep an eye out when I am going to liquidations again.

[DArBad]

Gents,

Thank you to everyone. The gun is a well known cheaper brand. I like it, but I really would like to change the ambidextrous thumb safety to a one side GI style.

I have all the thumb safety, the hammer pin, and sear pin. All from Fusion. But fitting first to see if everything fits, that's where I found the problem.

The gun is cerakoted. I tried scraping the hole with a jewelers fine file but the pins still wouldn't fit. Maybe, I'll just give it to a gunsmith.