I received a couple of PvtRyan's 1911 parts kits and wanted to start building my first 1911 using a KT frame that I purchased about two years ago. This particular frame needs to have the trigger slot and radii for the barrel seat cut. Here are my first impressions:
I figure that the trigger slot can be cut using a keyseat cutter, but I'll need to turn down the shank in order to move the cutter into the cutting area behind the trigger guard. When I say "trigger slot," its really the two recessed areas that the trigger "skeleton" rides in. (I wish I had a better understanding of the 1911 anatomy :p ). I believe a 1/2" keyseat cutter coming from the top of the frame ought to do the trick. The hard part is knowing where to stop! There is no real landmark in which to index off of -- at least from what I can tell anyway. How critical is this cut and what pitfalls should I look out for?
The radii for the barrel seat is called out in the plans as 0.348"+.005. How the heck do I find a ball end mill that size!?! :( I'm sure there has to be an easier way to correctly cut this area but I'm at a loss for ideas. I lent my Kuhnhausen books to another member but I doubt that even those would be of much help to me.
I think the rest of the build should be straight forward. If someone could point me in the right direction for the other stuff I'd be plenty grateful.
I just realized that I can probably use the magazine release hole as an indexing point for the trigger slot. Am I on the right track here or not?
Okay, I've been doing so more measuring and realize that the OD of the bbl hood is about .6835". The closest I can find is a 5/8" ball end mill, which is .6250" (R.3125"). If I use the 5/8" cutter and move it up and down the y-axis .029" from center, will I be able to lap the rest of the radii with some 600 grit and WD-40? I feel like I'm just drawing at straws right now...
BTW, Frank's kits are awesome.
sounds like a good plan to me. I would do it, just take your time and measure A LOT...s hould work fine.
You are correct Ale, I have in my possession a complete set of the Kuhnhausen .45 books, and there is nothing in them that will help you with this. However, I can tell you that I was able to cut the barrel seat nicely with an 18mm diameter long endmill held at the very top of it's shank in the collet. You are welcome to borrow my 18mm endmill for your task.
As for the the trigger bow slot, yeah I think the only way to do this is with a shaper from the rear, or with a 1/2" keyseat cutter from above. I will do a quick compare to make sure the latter is doable with commerically available cutter dimensions, and post back.
That 18mm end mill would definitely do the trick. However, the KT frame has the full-length picatinny rail on the bottom that I was planning to keep for a "Monolith-type" build. Unless your end mill is 6" long, I would need to cut down the dust cover. I still have the four frames that "Pops" gave me so I'll definitely use it for those builds.
I don't know what a shaper is but I'm sure that a keyseat cutter from the top would work with the shank turned down about 1/8". I'll have to order one of the "value-brand" cutters since I don't want to modify my Keo just for this operation.
I may start working on Pop's frame first and use KT's as a guide until I decide what to do.
aleaddict:
First off cant help you on the trigger bow track as I have not ever cut one
yet but I am sure with the right woodruff cutter it should not be hard. I
would use the largest diameter one you can get your hands on that will fit in
the magwell that does not exceed the trigger bows height You want to cut this
track so that when the trigger is dropped in the frame, the back of the
trigger bow is slightly less than flush with the frame. Hope that makes sense.
As for the barrel bed area of the frame I would do it as dogbert mentions and
not use a ball end mill bit, use a conventional bit and have frame rails
sitting vertical. Of course you will need a long mill bit but there out there.
I also agree that a shaper sounds like a good idea on the trigger track but I
do not beleive you could get the radius that is needed at the end of the
trigger track with a shaper, I beleive only a proper radiused woodruff bit is
going to get you that.
Everything you said makes perfect sense. The "Pops frame" has the back of the trigger bow sitting about .065" below the flat of the inside grip area. If I use an angle plate for my setup, I should be able to slide the trigger in and out of the trigger slot between cuts. Besides, I don't think my keyseat cutter is long enough to reach the mag release hole as an indexing point. I'll just use the "cut for effect" method and hope for the best.
I suppose I'll have to cut down the dust cover on the KT frame for the barrel channel after all. It will certainly make this operation a lot easier but limits the functionality of the full length pic rail.
I'm sort of torn between which frame I should start on first. The KT frame is more finished but the ss slide I've been sitting on for a while now looks like it was made for the frame from Pops. There's a "fun show" this weekend so I might see what they have while I chew on this decision...
PLEASE POST SOME PICTURES OF THE * POPS* FRAMES AND THE AREA OF YOUR CONCERN, OR DO A COMPARISON WITH KTS FRAME TO POPS FRAME> IM TOTALLY LOST < THOUGHT ALL THAT WAS DONE ON A KT FRAME , BUT JUST RAILS NEEDED DONE?
Don't know if this will help, but you might want to give one of our Staffers, Justin, (jwh02017) a shout and see how he did it. If I remember correctly, he made a 1911 frame from billet, and used a specially made cutter to do the trigger slot, but I think there was still some hand work that needed to be done. His web site shows some of the detail of the machining, but I am sure he would be more than willing to provide any info you might need.