1911 Slide Work

M

M@tt

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Hello Everyone,
This is my first post outside of my introductory post.
Quick question. I am fairly new to machining, but would really like to flat top my Sig 1911. From everything I have read and seen this is a rather simple task. Has anyone done this and does anyone have pointers or tips?

Also, how difficult is it to finish a 80% slide?
 
M@tt said:
Hello Everyone,
This is my first post outside of my introductory post.
Quick question. I am fairly new to machining, but would really like to flat top my Sig 1911. From everything I have read and seen this is a rather simple task. Has anyone done this and does anyone have pointers or tips?

Also, how difficult is it to finish a 80% slide?
Click to expand...

My best advice and opinion is to practice a good bit on test pieces and chalk-up some hours before working on anything of a serious nature. To an experienced mill operator, most operations are pretty routine. Properly clamping the workpiece when working on firearms is often a challenge and frequently requires making jigs and fixtures. If a part slips-out while you're working on it, it usually ends-up in the scrap pile. The next hurdle is knowing the material you're working with and knowing what kind of tooling, feeds and speeds are appropriate. Chances are, a slide will be made of moderately hardened alloy steel. Also, folks will need to know what kind of mill and tooling you have available. The job will be approached differently depending on what equipment is at-hand.


Ray
 
From everything I have read and seen this is a rather simple task.
Click to expand...

The simplicity and ease of performing a machining job is a relative concept that highly depends on the skills and experience of the one who would actually do it.
We really have no way of knowing the level of machining skill and experience you already have.

Like what has been previously suggested it would behoove you to first practice on something comparable or similar to it ( before hitting on the actual piece) and only then would you be able to know how simple or difficult it is.
 
I have a better than average shop and thousands of hours experience. Have built my share of gun projects, . I have also machined a 1911 slide from a casting. I don't know if you would say it was 80%....But I'll venture my thinking on the subject- lots of work. Had to make perhaps 15 special cutters and fixtures.. I doubt a newb would have a satisfactory outcome...I've got 6 more of the slide castings in a drawer somewhere and really doubt I'll ever work up the ambition to use them. I just keep'em because I never sell anything.
 
I'm not sure what work is involved with an 80% slide - and there's not really much reason to take a slide to that level of completion and then leave it unfinished. Since there's no serial number involved with slides, I'd think the main interest would be to build one from the raw casting, as mentioned above.

I have a couple of 80% frames that I need to build. You need to mill in the slide rails, drill a couple of pin holes, and that's about it, other than the usual fitting for barrel, link, and slide.

Also as noted, flatting the top of a slide looks pretty easy, but probably 90% of your work will be in setting up really stable workholding, researching the metal and selecting the proper cutter, feed rate, speed, and coolant, and then the finish work so it looks pretty (without rounding all the edges off). Last time I looked, you could still buy surplus slides from Numrich Arms or SARCO for pretty cheap. I'd buy a couple of those for practice pieces before sticking the slide for a SIG on the mill table. It may save volumes of tears in the long run! ;)

Mike
 
Thanks for the replies.
I agree completely with what everyone has stated.
If I ever did anything it would be on a slide blank first.
My history/expierence is as follows. Certified CAD technician, CNC trained, various tool making expierence on manual benchtop lathes and mills. I have built 10+ AR based rifles and have built one 1911 from a "builders'' kits requiring full fitting.

I currently have a LMS HiTorque Mill
 
I have built my fair share of 1911s for competition and carry. The flat top mod is a popular mod and does aid a bit in sighting, but I think its appeal is mostly aesthetic. One area to be cautious of is the locking lug recesses in the slide. Take too much off the top and you get very thin in this area. Also you have to consider the sight mounting. The front sight, whether staked or dovetailed, will most likely have to be redone. I would definitely practice on the casting first.
As for finishing a casting, like Alphawolf said; lots of specialized cutters and set-ups. They do make for good practice, but unless you are set up to heat treat the finished product, it will not last long in an untempered state.
 
Here is some good advise on this subject...if your slide has sight dovetails cut in you might not b able to clean them out, so you would have to stop your flat top short of the sights, for this cut you would need to position the slide horizontally using the end mill side flutes, the radius of the end of the cut depending on the size of your end mill. Also even though you dial in the top of the slide to .0000 the cut might come out wider from one end to the other...most slides I have cut are not even on the round. What I do is take a light cut and adjust my vise to compensate for the uneven radi of the top, sometimes it takes 3 to 4 light cuts adjusting the vise to get it right.
 
As stated practice first make sure everything is square and level in whatever you are using to hold the slide.I have prcticed on some 1 inch round stainless with a 1/2" end mill and it works fine.Will try the slide when I finish setting up the DRO's I just purchased from Dave on this site.Also am going to do serrations and will post pics when I get them done.
This site and the few others are a real big help to a new machinist like myself. I am also in the process of doing a P12 para frame that was from Sarco. I have started that and am making my own jigs as I need them.
John
 
Here is an STI Edge that I flat topped and serrated the slide, also put a French border in but its hard to see, this slide was not concentric on the round and the vise had to be adjusted a couple times to get the flat the same width from front to back.....so be warned....

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