Harp Custom 1911 Pistols; Cutting Hammer Hooks on a Milling Machine, stoning a 1911 sear and trigger job.

Harp Custom
We are custom 1911 Pistols

I build precision custom 1911 pistols and custom pistols one at a time using modern machinery and tools. I specialize in custom 5"1911 Government model style pistols in .45acp and 3.5" Officer model, 4" 1911 and custom 4.25" Commander 1911 pistols...


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1911 Gunsmithing Articles

by Troy Harp

The gunsmithing articles on this page are intended for the purpose of showing you some insight on how I do my 1911 pistol work in my shop and to educate a potential customer. Although a lot can be learned by what I show, please understand that the majority of the work I demonstrate does not include how I set up many of the machining steps. I don't describe or show for the sake of time and my own hard learned set ups all of the fixtures or how to set up many of the gunsmithing operations.

One example is how I set up the hammer hooks for the milling operation. I have developed a way to align the pin hole in the hammer with the axis of the frame hole to ensure that I am machining the hooks relative to the alignment of the sear and hammer when in the pistols frame. Another example is how I professionally blue carbon steel pistols using Caustic Hot Bluing Salts and the great complexity in acheiving an ultra deep and black finish.

However, you will be able to gather a great deal of insight on how I build my pistols, the hard work and the great precision that goes into building a true precision custom 1911 pistol.

My goal was to design and build a website that offers much more than the occasional pistolsmith or company site that shows a photo of a guy sanding a part or holding a slide and a file in both hands.

Please feel free to go through all the information and I put in the articles and let me know if I can help you with a possible custom 1911 build designed by you and not some "custom production pistol" where you can choose very little about your design other than pre-designed models.




Contact:

Harp Custom Pistols
33301 Osawatomie Rd
Osawatomie, KS 66064
Phone 913-244-2329
Fax 913-755-3041






Technical Note:

The hammers hooks face relative to the hammers pivot hole is important with the sear preparation. The sears primary angle should be 90 degrees relative to the center of the sear pin hole. The break-away angle is a seperate angle that is roughly 15-20% of the sear nose.

Changing the geometry or sear/hammer relationship can be accomplished by simply changing the sears primary angle to be more neutral or positive in it's engagement...

Which means it isn't necessary to be less than square on the hammer hooks. However, the special ground cutter I use to cut the hammers hooks ensures, with a great deal of precision, that the hooks are at least square or 89.5deg less than square and trues up the contact surface relative to the sear and frame pin hole. Meaning you will have perfect contact when assembled and fired, precision matters...







Exotic Wood Custom 1911 Pistol Grips For Sale; Many exotic woods to choose from
Custom 1911 Grips
Many Extotic Burl Wood Blocks To Choose From
I build custom 1911 grips out of many different styles of woods and fit them to your frame during the build. I also build grips for an existing pistol you may already own. Please take a look at some of my videos that show the acrylyic stabilization process and how I build my custom grips.






Custom Leather Gun Holsters By Brigade GunLeather
M-11 IWB Leather Holster One Of My Top Selling Best Concealed Carry Holsters

All Harp Custom Pistols come with a custom leather holster of your choice of style. Built by Brigade GunLeather, which is my custom leather holster business for the last 17 years. Yes, I am a full custom pistolsmith and a full custom master leather maker as well. All my builds come with one.


 

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Join us at Harp Custom Pistols YouTube Channel. View the latest 1911 gunsmithing videos and pistolsmith information.


 

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Read the latest blogs posts about custom 1911 pistols and new things happening.

Come read the Harp Custom Pistols blog. You may read the latest posts about what is happening with the latest custom 1911 projects.



 

 

1. Setting up on the Milling Machine to cut the hooks.

After careful measuring of the frame hole where the hammer pin rest in and insuring the hammer is set up in the milling vice fixture, I begin to measure and adjust so I can use my special 5-flute carbide cutter to re-cut the hammer hooks to 89.5deg at a depth of .022. See the photos below of part of the set up.

Factory drop in 1911 hammer
This is a photo of a new big name brand "drop in" match hammer, as you can see viewed at 20x the surface is not good.
Measuring 1911 hammer hooks for cutting
Part 1 of 2 I am set up on the mill, after measuring, clearly you can see the lack of precision from so called "drop in" parts.
Measuring 1911 hammer hooks for milling
Part 2 of 2 Note the difference in the height of the face of the hammer.




End mill for cutting 1911 hammer hooks under square
A special ground end mil cutter that is ground at 89.5 degrees. Or another way to say it, it is 1/2 degree less than square.
Cutting 1911 hammer hooks
View of the hammer as I begin to start machining the hammer hooks. You can see how un-even things were to start with.

Cuttin 1911 hammer hooks

In this photo I am almost finished re-cutting the hammer hooks...

Milling 1911 hammer hooks to 89.5 degrees 1/2 degree less than square
This is a photo of a new big name brand "drop in" match hammer, as you can see viewed at 20x the surface is not good.
1911 Hammer hooks are now level after cutting
This is a photo of a new big name brand "drop in" match hammer, as you can see viewed at 20x the surface is not good.
After cutting 1911 hammer hooks
This is a photo of a new big name brand "drop in" match hammer, as you can see viewed at 20x the surface is not good.


2. Final Finishing on the newly cut hammer hooks and sear.

After machining the hammer hooks and surfacing the primary and secondary angle on the sear nose I begin to polish the newly cut hammer hooks and sear primary and secondary angle using three different lapping compounds that vary from 800 grit to 2000 grit.

Stoning the sear primary and secondary angles
Using a fixture I stone the sear primary and break-away angle
Polishing the sear nose with up to 2000 grit lapping compound
After stoning I begin to precisely polish, under magnification, using 3 different high grit lapping compounds
Fully prepped sear nose, primary and secondary angles finished
Using a fixture I stone the sear primary and break-away angle

Sear nose contact bi lateral on the hammer hooks evenly
After the trigger job has been completed, this photo illustrates the even contact across the sear on to the hammer hooks
 

 





After careful measuring of the frame hole where the hammer pin rest in and insuring the hammer is set up in the milling vice fixture and running true to the frame pin hole, I begin to measure and adjust so I can use my special 5-flute carbide cutter, spinning at 3,000 rpm, to re-cut the hammer hooks to 89.5deg at a depth of .022. A precision cut that simply can't be duplicated by an automated means and certainly not via the old fashion stoning or filing by hand.




Prepping the sear primary and secondary (break-away) angles to agree with the newly cut hammer hooks. The sears primary angle needs to be 90deg to the center of the sear pin hole.