assaulter Posted May 22, 2018 Share Posted May 22, 2018 I'm about to start another 2011 build. Have any of you used a keyseat cutter to open/lower the slide rail ways on the frame instead of taking all the material off the bottom of the slide? It looks like I'll need to take almost 10 thou off the bottom of the slide. I thought kuhnhausens book advised to not go farther than .113 on the slide? I need to look it up again to be sure. It would certainly be easier to take it off the slide to avoid making an error with the keyseat cutter. So, what's the most you would take off the slide before you would modify the frame? Strictly talking about the slide rails on the frame ways. Link to comment Share on other sites More sharing options...
Broncman Posted May 22, 2018 Share Posted May 22, 2018 (edited) I would think that since the slide is the "disposable" item, I had rather take it from the slide? .010 would not bother me. Where do you need to take .113 from??? Edited May 22, 2018 by Broncman Link to comment Share on other sites More sharing options...
assaulter Posted May 22, 2018 Author Share Posted May 22, 2018 (edited) I had to look it up again. It's actually .114 and he states this is the minimum vertical slide rail height. My frame ways are .109 in height. Slide is .119. Edited May 22, 2018 by assaulter Link to comment Share on other sites More sharing options...
ACree Posted May 22, 2018 Share Posted May 22, 2018 What slide and frame? Knowing which manufacturers will help in determining the math. You are correct on the .114 minimum. I have used a keyseat-type cutter to adjust frame rails. Dave at Evolution Gun Works sells a really nice cutter that does an excellent job! Andy Link to comment Share on other sites More sharing options...
assaulter Posted May 22, 2018 Author Share Posted May 22, 2018 Sti 2011 frame and Caspian slide. Link to comment Share on other sites More sharing options...
Brazos Custom Posted May 22, 2018 Share Posted May 22, 2018 Might want to check your measurements again. I have never seen an STI frame that measured 0.109. They are all between 0.112 and 0.114. Link to comment Share on other sites More sharing options...
ACree Posted May 22, 2018 Share Posted May 22, 2018 (edited) You are seeing first-hand how various manufacturers have muddied the spec waters with changing the design to fit other components instead of sticking to one standard. STI cuts their frame raceways small because the make their slide rails are .110 +/-. I have an STI frame on hand that has raceways that are .111 as measured with a gage pin. Phoenix Trinity 2011 frames have frame raceways that are .115. JEM makes their frame raceways .117, but will go .115 or .114 if asked prior to machining. If you want to keep the STI frame, I would suggest you buy and STI slide. If you want to keep the Caspian slide, go with a JEM or PT frame. If you go with the JEM or PT frame you can address the bottom of the slide rails. Andy Edited May 22, 2018 by CCG Link to comment Share on other sites More sharing options...
assaulter Posted May 22, 2018 Author Share Posted May 22, 2018 I measured with a gage pin and got .110. .111 fits tight on one side and not the other. Does STI sell a commander length slide? That's the plan for the build. It looks like there is about .010 at the bottom of the frame slot before it is flush with the dustcover. I could try to take .004 off the bottom of the frame and .005 off the slide, but that could be easy to screw up the frame. Will a staggered tooth keyseat cutter do what I need? Would taking .009 off the bottom of the slide really be detrimental to the gun? Link to comment Share on other sites More sharing options...
theWacoKid Posted May 22, 2018 Share Posted May 22, 2018 (edited) 28 minutes ago, assaulter said: Would taking .009 off the bottom of the slide really be detrimental to the gun? Personally, I don't think I've taken that much off, but I'd do it without hesitation and wouldn't consider any other option. Could it be a problem? I guess I'd be willing to find out since I can't come up with why it would be a problem and I've yet to see or have a slide failure in that area. It's three other areas I'm always worried about. Edited May 22, 2018 by theWacoKid Link to comment Share on other sites More sharing options...
ACree Posted May 22, 2018 Share Posted May 22, 2018 (edited) It can, but it depends on the stacking tolerances of the slide. If you have a large gage pin, even a .250 if that is the largest you have, grab it. Put your slide upside down in the vise and insert the gage pin so that is lays in the "bottom" of the slide where the slide lugs are located. Take a depth mic and tell me the measurement from the bottom of the slide rails to the gage pin (don't forget to add in the diameter of the gage pin). Edited May 23, 2018 by CCG Link to comment Share on other sites More sharing options...
zzt Posted May 22, 2018 Share Posted May 22, 2018 5 hours ago, CCG said: If you want to keep the STI frame, I would suggest you buy and STI slide. If you want to keep the Caspian slide, go with a JEM or PT frame. If you go with the JEM or PT frame you can address the bottom of the slide rails. +1, except if you go with a JEM frame, order a JEM slide and have him machine fit (interference) it for you. No charge, and makes life so much easier. BTW, I also have a Caspian slide fit to a JEM frame. No problems with either. The most I have ever had to take off the bottom of an STI slide to fit to an STI frame was .006". Link to comment Share on other sites More sharing options...
assaulter Posted May 23, 2018 Author Share Posted May 23, 2018 20 hours ago, CCG said: It can, but it depends on the stacking tolerances of the slide. If you have a large gage pin, even a .250 if that is the largest you have, grab it. Put your slide upside down in the vise and insert the gage pin so that is lays in the "bottom" of the slide where the slide lugs are located. Take a depth mic and tell me the measurement from the bottom of the slide rails to the gage pin (don't forget to add in the diameter of the gage pin). Ok, I used the dro on the mill and averaging tenths I get .8455 from the bottom of the slide to top rear top lug face closest to the breach. I appreciate everyones help. I've got another sti frame that I measured .112 with a gage pin. Link to comment Share on other sites More sharing options...
ACree Posted May 23, 2018 Share Posted May 23, 2018 That slide and frame should not go together with those measurements. Taking off .010 from the bottom of the slide will reduce the space that linked barrel has to properly function. You will likely have to reduce the bed and push back the VIS to get proper clearance between the barrel hood and the slide when cycling. I would suggest going with the STI slide for the STI frame and save the Caspian for another build. Andy Link to comment Share on other sites More sharing options...
assaulter Posted May 23, 2018 Author Share Posted May 23, 2018 I'll have to do another frame if I go that route, since this is a commander build and I can't find an STI commander slide. I'm trying to visualize how reducing the bottom slide rail thickness or lowering the bottom ways in the frame affect the timing. It seems like the slide wouldn't sit any lower because it is limited by the frame rails in the slide ways. I can see it if I reduced the top deck. Can you help me understand that relationship. Thanks! Link to comment Share on other sites More sharing options...
ACree Posted May 24, 2018 Share Posted May 24, 2018 I apologize for leaving that hanging without a more clear explanation. If everything else about the slide and frame were to spec, then additional thickness of the slide rails would be inconsequential. If everything else was to spec, your overall "stack" in measurement would have been closer to .850" or so if your slide rail width was .119 (which was never stated above, other than you said you needed to remove .010 from the slide rail to fit the first measurement you provided for your frame raceways as being .109). You stated that your vertical stack measurement was .8455". That measurement, along with the position of the slide stop pin in the frame, the location of the bottom of the frame raceway and the SSP, and the inner dimensions of the slide all add up together. Having reviewed the numbers again before replying, I would actually reject that slide. Here is why. The stacking tolerances within the slide, which have to allow room for the barrel to lock-up and rotate downward to unlock and engage the frame VIS and bed correctly, has a recommended value. Your slide measures right on that recommended value. If the bottom of the slide rails are .005 more than the .114 recommended value, then the -.005 amount has to come from somewhere else within the slide. Having that as a starting point of a build could cause you some headaches down the road. Link to comment Share on other sites More sharing options...
assaulter Posted May 24, 2018 Author Share Posted May 24, 2018 I get what you are saying now. Thanks for taking the time to explain it. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now