Need specs for S&W 1911 dovetail (rear sight)

[bdpaz]

Another rookie question here. I bought a Rock Island 1911 in .38 super as a base gun for "do it myself" projects to become familiar with 1911s. One of my first projects is to replace the sights so I ordered a set of Warren Tactical sights for S&W dovetail and I plan to have a machinist/shooter friend prepare the slide. He can determine how to cut the actual dovetail but I think the top of the slide under the rear of the sight must be cut down also. Does anyone know, or can direct me to, the specifications for machining the slide to accept the sight?

Brad

 

[Spartacus451]

It is the same as their other third gen autos. You can measure the sight to find out the dimensions. something like .200 x 65

 

[bdpaz]

Keeping in mind I'm a novice, that sounds like measuring the dovetail which we can do. It looks like there must be a notch cut out of the rear of the slide (with the dovetail extending below) and I don't know how deep that cut should be.

I have emailed Warren to see if the have the information or can tell me the height of some part of the sight relative to the top of the slide but I haven't heard from them yet.

Brad

 

[bdpaz]

deleted

 

[Onmilo]

Depth of the dovetail is the height of the sight base to the dovetail apex.
Use micrometer to measure then transfer to a depth guage.
Set this depth on a 1/16" end mill to make the initial cut and make the final cut with the dovetail cutter.

Using the end mill to hog out the center of the cut produces a cleaner, chatter free, dovetail and is a whole lot easier to fix if you boo-boo.

 

[RogersPrecision]

Ono,
Have you EVER personally done this?

 

[Onmilo]

Yes.
You want a walkthrough, OK.
1. Find the height of the sight dovetail usuing the method described.
2. Chuck up the slide in the mill vice using parallels.
3. Chuck up the end mill, find the Z plane of the part, set your Z1 plane and adjust your mill for the rough pass.
It is better to make these cuts on the X plane and not the Y plane so adjust your vice accordingly.
4. Make the rough pass, check the depth with a depth gage, adjust Z for finish pass and make Finish pass. Check depth again.
You should allow about .005" additional material for the dovetail pass.
5. Chuck up the dovetail cutter and adjust spindle stop for the height needed to make the rough dovetail pass allowing material addition for finish cut.
6. Make the cut, check and adjust your depth and make the finish cut.

You may need to clean up the edges with a file or stone and you will get a cleaner cut if you use a flood coolant sprayer.
Always use plenty of coolant in some form when using a dovetail cutter so it doesn't bind during the pass. HTH

 

[bdpaz]

I'm still confused! I have attached a jpeg showing the measurement I need. I don't see that I can assume the front edge of the sight is flush with the slide or that I have a reference between the top of the slide and any part of the sight. I'm hoping there is a standard for the "S& W dovetail" that gives the info I need, otherwise I will have to wait until I hear from Warren Tactical. My guess based on comparing this sight with the Sig version on my 229 is that the depth of the cut is .125in.

 

[Jim Watson]

Why would a S&W sight have anything to do with a Sig's?

I think you would be best off to return that sight and start over with a sight that will fit the stock dovetail of your Colt copy, or to get a Novak or Heinie where they will furnish you the dovetail dimensions.

 

[Rex B]

How hard can it be? The OP wants this for a learning process.
I'm doing the same thing, fitting a Kimber Target sight to a Sistema slide.
I haven't found the specs, but just measuring the profile and transferring that to the slide should get you in the ballpark. Key to my installation is knowing the height of the correct front sight, which is .180 on the Kimber.

 

[bdpaz]

Why would a S&W sight have anything to do with a Sig's?

I compared a Warren Tactical sight on a Sig to a Warren Tactical sight for a 1911 to see what would give the same height of the notch above the slide for both. As the notch dimensions are identical I would think the height above the slide would be similar, but I am not going to proceed on that assumption.

I am waiting to hear from Warren but I thought I might find the information more quickly if the specs for the S&W rear sight dovetail (the sight is made for a S&W 1911) are available.

Brad

 

[Onmilo]

From your diagram, if the S&W sight sits too low you would have to cut a dovetail filler and weld it in place before you make the cut.
If the S&W sight is too large you will have to mill a flat at the top of the slide to provide clearance.

Either will mean adjusting front sight height for poaim/poimpact.