Frame & Slide lapping?

[tightgroups]

My slide could be a little smoother on my SA GI and I was wondering if using some sort of lapping compound could be used to make it glide better? I do have some valve lapping compound but I need to check out what "grit" it is.

Comparing my SA to my Kimber, the Kimber feels like it is on ball bearings while the SA feels a little rough. Maybe I need to put another thousand rounds through this gun using something like Militech to condition the rails. After that I could just use use FP-10 or Weapons Shield for normal lubrication.

I just want to make sure lapping won't due any damage as long as I don't go crazy. I'm only looking to polish the rails not loosen the fit. Also, maybe I need to bend the sear spring leaf that contacts the disconnector in order to reduce some of the tension? I understand this needs to be done very carefully so the gun will function safely.

Thanks.

[David Rose]

tightgroups, lapping will loosen the fit. That is it's purpose. With a very fine compound, it may knock off the high spots more than the whole bearing surface. But right now, the "high spots" are what is keeping the slide to frame as tight as it is. It might be smoother, but it will be looser also.

David

[tightgroups]

Hmmm...very good point David, thank you. Do you think a new recoil spring ( A Wolf #16 and a FLGR would help smooth things a bit?) I was also thinking of using Militec and see if it is any smoother after treating it. I've heard of people tightening their slides to the frame using a small nylon faced hammer instead of a vise but the horizontal fit is very tight, the vertical is slightly loose. I've heard the the accuracy really isn't effected to much by tightening up the frame. Most of the mechanical accuracy is supposed to come from how well the barrel has been fitted.

I'm stumped at this point. What do you think makes my Kimber feel like it is on ball bearings while my SA GI feels rough? Dane Burns told me that my SA will never be as smooth as my Kimber. He said the kimber was smoother simply because of tighter tolerances but I refuse to believe this. Both pistols are metel which means if one is very smooth then the other can be worked on and attain the same level of fit and smoothness. What's your opinion on that David?

[cary Chin]

To lap your slide to the frame, do not use valve grinding compound, use aluminum oxide lapping compound instead. By using valve lapping compound, the residue compound will keep grinding on your slide/frame, even after you are done cleaning your gun of it. Aluminum oxide will convert to a lubricant after it's grinding capabilities have been used up. This was taught to me by the late Master Gunsmith Bob Chow.

Cary

[tightgroups]

Excellent advice Mr.Chin, thank you very much. Where can I get some of the Aluminum oxide lapping compound?

Thank you.

[Captain Eagle]

I use JB bore compound for that job. Dave Sample taught me that..................

[cary Chin]

If memory serves me right Brownells has it.

Cary

[Captain Eagle]

I would never lap in a factory gun. I would shoot it in. It would be a waste of time, as far as I am concerned.
You are right. I get it from Brownell's. I am on about jar number 20.........................

[Joni Lynn]

I thought lapping was done after the slide/frame fit was tightened. I would think it would smooth up after a good bit of use where lapping will cause additional wear right away which wouldn't otherwise occur for many thousands of rounds.

[Captain Eagle]

I have peened a few rails while I was learning factory gun tweaking. I used JB for that task also. I quit doing that very early on (20+years ago) becuase I got into building custom guns from oversized/undersized parts.
I use JB bore compound when I beat the slide and frame together with lead hammers. I call that the "Cold Swage" method. It keeps them tight for the life of the gun.

[Joni Lynn]

I had Clark's tighten the slide/frame fit on my Gold Cup, but just as I was told it would do, it has eventually loosened up just a small amount. The reason I was told is that one part is very hard and one while not soft, much less hard than the other.
It still shoots really well.

[Captain Eagle]

That is why I don't bother with that stuff anymore. I think the rails get softer when you peen them down. You do not make them narrower. You lower and spread them out. Then you fit them to the slide and pinch the slide back where it's tight when in lock up.

[MedSpec65]

I've used a crocus cloth (denim impregnated with jeweler's rouge) on the feed ramp, slide contact points and the slide and frame rails on my Kimber Custom II. The bottom of my slide looks like a mirror and it cycles like a dream.

[Joni Lynn]

I had a series 70 Gold Cup built up and took someone's advice to have Krieger Accu-rails installed. They certainly tightened up the fit but I don't know if I'd do it again or not.

[Mylhouse]

That is why I don't bother with that stuff anymore. I think the rails get softer when you peen them down. You do not make them narrower. You lower and spread them out. Then you fit them to the slide and pinch the slide back where it's tight when in lock up.

Wouldn't getting the pistol hardchromed or some other superhard metal treatment after squeezing keep the tight fit much longer?

[Greg Derr]

+1 on the JP, I cut it with some light lube.

[Devin]

I have a Springer GI as well and had experienced some grittiness when racking the slide as well. I'd bet it has nothing to do with your rails at all. Remove your slide and take a look at the disconector notch. For some silly reason, Springfield engraves the serial number here. The grittiness I felt was the serial number engraving rubbing against my disconnector. I took a very small, fine file and knocked down the raised part of the numbers as much as possible. I then grabbed my Dremel (I know evil tool for guns), put a 1" felt polishing wheel on it, and polished up the area with white polishing compound. I took it nice and easy, nothing drastic and stopped when I could barely feel the numbers when I dragged my fingernail acrosss them. On my pistol, the difference is remarkable, slide racking is now butter-smooth, it's not 100% perfect, but the grittiness is almost imperceptable.

I hope this helps out.
Devin

[tightgroups]

Thanks Devin. I noticed this also on my pistol and did the same thing as you only I used super fine sand paper (1000 and 1200 grit) and this solved the disconnector rail problem but my slide still feels gritty.

Greg,

What do you mean by " +1 on the JP" ? Sorry, I'm a little confused but I'm sure it's pretty simple and I just missed something obvious. Mabe it means "Dremel polish?"