Where to find 2000 grit non-embedding lapping compound?

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Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 4:04 pm

The RO that I have with a very tight slide to frame fit has not loosened a bit after quite a few rounds.  It was suggested to use 2000 grit non-embedding lapping compound.  Anyone know where I can find some of this stuff?  The finest grit that I was able to locate online is 1200 grit.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by DavidR on Tue Mar 17, 2015 4:06 pm

try extra whitening toothpaste, it has very mild abrasive, although I would just shoot it, lighter oil might help

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by spursnguns on Tue Mar 17, 2015 4:46 pm

Hello beeser,

If your RO is so tight that the slide is binding and not functioning properly; lapping is not the answer.  Mark it up with Dykem, find out specifically what is causing the trouble and address the specific area (hone, mill, etcetera).  Lapping will loosen everything up and is not a recommended technique by modern pistolsmiths.

If it is just tight; load more ammunition and shoot more.

Jim

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by DavidR on Tue Mar 17, 2015 5:06 pm

a blue sharpie will work too

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by CR10X on Tue Mar 17, 2015 5:10 pm

This one might be fun, so I'll jump in. 

Beeser:

What do you mean by "very tight slide to frame fit has not loosened a bit"?  Exactly what is the issue with the operation of the gun?  Feeding, extraction, can't get the slide open, was this with all the internals and barrel out and just slide and frame only, with loose barrel bushing installed instead, etc. 

Anyway, before changing what you have with lapping, as stated above lets find the specific area(s) causing the problem.   Particularly with or without the barrel installed.  Just some thoughts before removing something you just paid for.  

On the other hand you might have already done this and we just don't know it. 

Good shooting.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by spursnguns on Tue Mar 17, 2015 5:13 pm

Step away from the toothpaste.

Smile

Jim

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 5:51 pm

I gave the background of the tight fitting slide to frame fit in another thread but here it is again.  The last time the Range Officer was sent into Springfield (trigger job) I mentioned that the slide to frame fit seemed loose.  What they sent back was a fit that not only did not cycle rounds properly the slide would sometimes stick part way through the travel if cycled by hand.  It also just felt a lot tighter than it did new and compared to the 2 other ROs of mine.  I did what some of the members suggested here by firing it as is to loosen it up.  After about 500 rounds the fit seemed the same as before.  So, I brought it to a local gunsmith having experience with 1911s and he couldn't find any evidence of anything wrong other than it was a tight fit.  In other words he couldn't find it pinched or out of alignment anywhere.  He speculated that Springfield just put on another slide in response to my complaint and suggested lapping it in with 2000 grit (or no more course than 1200 grit) non-embedding lapping compound.  That's about the whole story.

Edit:  In response to Cecil's question, the slide sticks or does not travel smoothly even with the barrel and recoil spring removed.  As for feeding and extraction, rounds sometimes do not eject properly unless I increase loads from 3.8 to 4.0 grains of Bullseye.  I was always able to get reliable action out of 3.8 grains of BE as with my other .45 RO.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by Jerry Keefer on Tue Mar 17, 2015 6:03 pm

I had a RO in the shop last Sat.. The slide would stop and sit on the disconnector...It was in the shop for light hits..

(I do not lap...)

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 6:19 pm

Jerry Keefer wrote:I had a RO in the shop last Sat.. The slide would stop and sit on the disconnector...It was in the shop for light hits..

(I do not lap...)
Hmm... I just field stripped the gun and noticed that there was more wear on the slide where the disconnector comes in contact with it than I recall before.  Then again maybe I'm imagining things at this point.  If the disconnector is causing the binding what needs to be done?

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 6:46 pm

Looks like I'll have to be more pro-active in solving these 1911 issues.  Following Mr. Keefer's lead I looked a little more closely as to where the binding is taking place.  As it turns out the slide to frame fit is smooth and unobstructed at the beginning of its engagement but begins to tighten up when contact is made with the disconnector.  It further tightens when the slide comes in contact with the top of the hammer.  The disconnector pushes in flush with the adjoining surface with little effort so I don't think that's the problem.  However, I was surprised to find the top of the hammer coming in contact with the slide and being pushed down about 1/16".  Is this normal?  The wear mentioned in my last post was caused by the hammer due to the width of the wear marks.


Last edited by beeser on Tue Mar 17, 2015 7:17 pm; edited 1 time in total

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by spursnguns on Tue Mar 17, 2015 7:07 pm

I hate to tell you, beeser....um....the trigger is nowhere near the slide in a M1911.  Perhaps you can snap a photograph or two.

Jim

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 7:18 pm

spursnguns wrote:I hate to tell you, beeser....um....the trigger is nowhere near the slide in a M1911.  Perhaps you can snap a photograph or two.

Jim
Sorry, I meant hammer.  I corrected my post.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by dronning on Tue Mar 17, 2015 7:24 pm

spursnguns wrote:I hate to tell you, beeser....um....the trigger is nowhere near the slide in a M1911.  Perhaps you can snap a photograph or two.

Jim

You beat me to it.

Here is a great animation on the assembly of the 1911.
https://www.youtube.com/watch?v=4P4XJTKzKEU

- Dave

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Tue Mar 17, 2015 7:37 pm

I checked one of my other ROs (in 9mm) and the hammer also comes in contact with the slide but doesn't seem to push down as far.  Both of the hammers mentioned have been ground down at the contact area.  Is this one of those fitting areas?  And if so what is the criteria for fitting the hammer to slide fit?

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by Froneck on Tue Mar 17, 2015 11:42 pm

McMaster-Carr Has 1400 grit non-embedding lapping compound

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by Jerry Keefer on Wed Mar 18, 2015 7:28 am

Learn to read "Hi Spot" compound, by Dykem or Permatex..  use a scraper...Lapping is indiscriminate, by removing material from the entire area, rather than the source of the problem..

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by beeser on Wed Mar 18, 2015 8:44 am

Jerry Keefer wrote:Learn to read "Hi Spot" compound, by Dykem or Permatex..  use a scraper...Lapping is indiscriminate, by removing material from the entire area, rather than the source of the problem..
I gave up on the use of lapping compound as suggested earlier in favor of trying to find the source of the problem.  Efforts toward that end are shown in my most recent posts.  It appears that the slide is binding mostly by contact with the hammer.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by CR10X on Wed Mar 18, 2015 9:22 am

Take mainspring housing and hammer out of frame. Does the slide still stick? If not, check hammer strut for binding on grip safety or length when fully compressing mainspring. Be sure ejector is firmly pinned and has no play or contact with slide. Check firing pin stop for smooth transition to bottom of slide especially no overhang. Lots of other things to look for as well.

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by spursnguns on Wed Mar 18, 2015 10:26 am

CR10X wrote:Take mainspring housing and hammer out of frame.   Does the slide still stick? If not, check hammer strut for binding on grip safety or length when fully compressing mainspring. Be sure ejector is firmly pinned and has no play or contact with slide.  Check firing pin stop for smooth transition to bottom of slide especially no overhang. Lots of other things to look for as well.  

+1

....beeser,

You also write; that you are concerned that a load of 3.8 grains will not fully function "this" RO (that it needs to be 4.0 grains), where it will function "another one" that you own.  It is not unheard of that different minimum loads will be needed for different guns.  With the typical and expected variations one find in springs (their weights, their age, etcetera); adjusting your loads or changing spring weights is probably a more appropriate solution.

Jim

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Re: Where to find 2000 grit non-embedding lapping compound?

Post by Jerry Keefer on Wed Mar 18, 2015 2:17 pm

beeser wrote:  It appears that the slide is binding mostly by contact with the hammer.
Nearly all guns, exhibit a condition called "Over Cock".. It insures the hammer hooks catch the sear.
The over cock travel can be minimized, and should be, by surface grinding the hammer face. The old procedure of contouring the hammer face is seldom seen, but is a huge aid to wad cutter guns.  

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Re: Where to find 2000 grit non-embedding lapping compound?

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