What is the best stone for trigger/sear smoothing?

[jmstr]

I want to smoothen out a hammer/sear interface, without changing angles. Thus no dremel tools.

I was told to get an arkansas stone to do the work but found that Brownells sells Arkansas Stones, India Stones and Ceramic Stones.

For light smoothing and not major metal reshaping, which do I want to use?

[Bill DeShivs]

Ceramic.

[jmstr]

cool. A nice, focused response.

But, why? I would like to know for future projects which goes with what type of project best.

[Powderman]

I will second the ceramic stones for the final polish. Recommendation--if you're working on something like a 1911, get a hammer and sear jig. If it's another semiauto pistol, see if there is a "Shop Manual" (Kuhnhausen) written for it.

If, on the other hand, it is a revolver--particularly a Smith and Wesson, don't stone it--not even a little bit. You can do a fine tune up on a Smith and Wesson revolver without ever touching the hammer or trigger interface.

[jmstr]

It's an HK USP.

I have the armorers manual, but don't know if there are other manuals.

Do any of you know of a Kuhnhausen-quality book on the Browning Hi-Power?

I'll follow the advice and leave the sear surface alone on my S&W 629-thanks for the tip.

does the same thing go for Ruger GP100s?

[Bill DeShivs]

The ceramic stone is the finest of the three. You can do less damage with it.

[montelores]

How should one properly use a stone?

Thank you,

Monty

[Rifleman1776]

I have used all with success, plus fine diamond. Just use carefully.

[mete]

www.spyderco.com has a nice collection of ceramic stones which I now use .The square and triangle are most useful.

[HiBC]

I'll agree likely the ceramic would be the best.I have only used them for knife sharpening.
Hard arkansas is a natural stone.You can get variable quality.I have not seen a bad hard arkansas from Norton.A Norton Hard Arkansas is a very good stone.Indias are great for many things,but not for what you are doing.
There is more to it than getting a stone.
A classic lesson for a european machine trades student is to take a lump of steel and file out a cube,say 1.000,flat,square,parallel,and to size,within .001 or so.
You don't want to crown,or round,or take the sear surfaces to another angle,or out of square side to side.
That is why they make sear jigs.
If you are determined to free hand it,that little bitty flat surface,you have to feel it become flat on the stone.It has to stay flat on the stone.you might give it 2 or 3 strokes a couple inches long.Then stop.
Imagine the tool finish you are stoning.Peaks and valleys.You only need to flatten the peaks enough so they dont fall in the valleys.Let the valleys hold oil and clean away contaminates.
With a jig,all the angles are in the tool.The stone is guided.You get correct results

[Vt.birdhunter]

Sandpaper in your local automotive store is availabe in 800, 1200 grit. Laid across a piece of plate glass, it makes a fantastic polishing surface. It can also be glued, folded and shaped onto crude tool handles as needed.

[mog]

Some Arkansas stones may be in fact too fine. A very good Arkansas will also be twice the price of ceramic and both break easily if dropped. India is good for quick removal of a lot of material; fine ceramic is good for sears along with a pull or two of Arkansas if you have one.
The most useful will be a stone long enough- four to eight inches- flat with squared sides. Use a bit of oil to float the metal off the surface. Remember that an overpolished metal surface may be too slick and might have no tooth to hold lubricant when re-assembled so you wind up with a metal-on-metal engagement. Cutting jigs are great if you do a lot of triggers but Brownell's tool steel or Wilsons(?) stainless steel $30 sear jig w/shim will be fine for the occasional job.-mogwan

[geetarman]

You can Google "Paul Gesswein" and get to their catalog of different types of stones.

I have Degusset synthetic ruby stones that I use for any fine work.

They are, hands down, the best stones I have ever used. They are also the most expensive. You can get them in different grits.

The set that I bought for $40 in 1966 is almost $400 today. I am still using mine.

If you drop them, they will break.

Degussa calls them "Ruby Stones" for their color. They are made of pure aluminum oxide.

I worked in metrology for over 40 years and these stones work well for taking the buurs off of gage blocks without destroying the overall surface and ruining the ability of gage block surfaces to wring together.

Be advised you will pay dearly for them.

Geetarman

[longrange08]

I would say that if you do not know this than maybe this is work you should avoid as your treading in dangerous water when dealing with trigger sear engagement.