Interesting or odd - hand fitted thumb-piece

[Emop]

Do I have a "special" thumbpiece, or just an everyday fitting issue of the late 70's era Smiths?
I recently bought an excellent nickel 29-2 and had an opportunity to compare it to another that could be a twin sister. The only thing I saw that was different was the cylinder release thumbpiece. One was un-touched that "dropped-in" and the other (mine) was totally fitted and re-shaped except the checkering. The lug was shortened and narrowed to fit the hole and it seats closer to the frame, and the rear edge that's tapered & curved under was filed "flat" on the radious behind the checkered depression which makes it taller and sharper. The other, un-touched, part did not fit my gun but I did notice that mine seats a bit too close to the frame and when pressed is leaving some scratch marks behind it.
I would like to try to "fit" a new one but have no idea why this was necessary when it was built... if it was intentional or something the gunsmith did to enhance the fit (back in the day) or simply the parts back then varied and some needed fitting... or the smithy began with the wrong part and got far enough to finish and send it along for plating!
This is obviously not an issue other than protecting from some hidden scratches on my 29. Both mine and the other are beautiful guns and both mechanically perfect! Just looking for a fun project that's 100% reversable if it doesn't pan out, and I retain the original factory part!
Any insights guys?
I have some pic's and will publish if this attracts some attention. Sorry for so many words for such a little topic!

 

[muddocktor]

Pictures are worth a thousand words. Let's see it.

 

[Emop]

Pictures are worth a thousand words. Let's see it.

Thanks for the interest!
Here are the photos. I tried to keep the "fitted" one on the right side.

 

[AlHunt]

Definitely the one on the right has been molested and not very well. Does the unmolested one fit in place of the modified release?

Edit: I see where you said it doesn't fit. It'll be interesting to see what the collective wisdom has to say.

 

[handejector]

Two different eras.
They used to be a machined part.
Later, they became investment castings. You can see the mold seam on it.

 

[jhnttrpp]

If you decide to file or otherwise grind on a nickel plated part what is your plan to deal with the loss of the plating. It is easy enough to remove the offending material.

 

[stu1ritter]

Jerry Miculek, in his "Trigger Job" video shows how to relieve the thumb piece on the end by (I think) .040" to lighten the tension on the bolt and it looks like exactly what was done to yours, but, he does not call for trimming the thickness at all. The thickness part of the mod seems to be in the Bubba division for some unknown benefit.

Stu

 

[Shark Bait]

I guess I'm not seeing the issue. But the one on the left is metal injected molding (MIM) and the one on the right is machined, which makes it earlier. A 29-2 should not have any MIM parts.

 

[iPac]

Two different eras.
They used to be a machined part.
Later, they became investment castings. You can see the mold seam on it.

Good catch.

The "filed" one is done as part of a tuning job to relieve pressure that may hinder cylinder rotation slightly. Nothing wrong with that modification.

Other than that, I don't see anything wrong with the "filed" one. I'd just leave it be.

 

[Emop]

Jerry Miculek, in his "Trigger Job" video shows how to relieve the thumb piece on the end by (I think) .040" to lighten the tension on the bolt and it looks like exactly what was done to yours, but, he does not call for trimming the thickness at all. The thickness part of the mod seems to be in the Bubba division for some unknown benefit.

Stu

The video I'm familiar with... "How to install a spring kit (trigger job) with Jerry Miculek" doesn't show any work done on the thumbpiece. Do you have a link to the one you mentioned.. I'm curious about that modification to thumbpiece and what it accomplishes in terms of the improving the trigger function? Thanks for the help!

 

[Emop]

To the best of my knowledge, which is limited, and certainly when it comes to action work, I was of the understanding that the thumbpiece is an external part, a tool so to speak, used only to actuate the bolt in order to open the cylinder. Mention has been made above that some modification to that part can enhance the trigger pull, or action in some way.
Can someone clarify this for me? Id like to learn about how that works and exactly what is the necessary thumbpiece modification that makes it do that job. I'm not disagreeing.. just not familiar. Thanks for the help!

 

[Emop]

Good catch.

The "filed" one is done as part of a tuning job to relieve pressure that may hinder cylinder rotation slightly. Nothing wrong with that modification.

Other than that, I don't see anything wrong with the "filed" one. I'd just leave it be.

I believe it works well as-is also, except that it sits low enough to scratch the frame a bit, but functionally fine.
Please see my post #11 That and it does look like its been Bubba'd quite a bit but it also appears to have been modified before it was nickel pated at the factory. It's sort of a "who done it" thing for me also
This is a forty year old Smith that looks like it's not been fired mote than test-firing at the factory when it was built... Absolutely pristine!

 

[Emop]

If you decide to file or otherwise grind on a nickel plated part what is your plan to deal with the loss of the plating. It is easy enough to remove the offending material.

Very good question. If I can find the correct forged thumbpiece for this 29-2 in nickel, I may only need to file the lug to fit it to the frame. I really don't know if it will require plating that area?
If it does, I'll get a blued one. Much easier to find new one, and I'll have it plated after fitting.
This is all just to restore it to its original configuration only, considering it's a collectible.

 

[Dave.357]

Would a .002 shim solve your problem.

 

[Emop]

Would a .002 shim solve your problem.

It might solve the rear dragging on frame problem. What shims would fit a bolt//thumbpiece?

 

[Dave.357]

You would have to craft it your self

 

[zephyr]

The video I'm familiar with... "How to install a spring kit (trigger job) with Jerry Miculek" doesn't show any work done on the thumbpiece. Do you have a link to the one you mentioned.. I'm curious about that modification to thumbpiece and what it accomplishes in terms of the improving the trigger function? Thanks for the help!

It's covered in his Trigger Job DVD, this one:

Gun Video Trigger Job: Complete Action Tuning S&W - MPN: X0201D

 

[Emop]

It's covered in his Trigger Job DVD, this one:

Gun Video Trigger Job: Complete Action Tuning S&W - MPN: X0201D

Thanks... I was searching Youtube.

 

[spdguns]

Is it possible someone relieved it to prevent the thumbpiece from rubbing on the side of the frame and skinning up the frame?

 

[Emop]

Is it possible someone relieved it to prevent the thumbpiece from rubbing on the side of the frame and skinning up the frame?

I wish I could answer that but if it was part of the reasoning for the alteration... it was a failure... because the uneven reduction the height of the lug (what I'm calling the portion that enters the frame hole) in addition to everything else you see in the photos, it sits too low and now does rub the frame, and has left some light scratch marks.

I am clueless as to the reasoning behind this alteration although mention has been made in a previous post that it can enhance the action, but other than the Jerry Miculek "Trigger Job" DVD that was referred to, that I have not seen... I am unaware how it could be of benefit.

What I see as being the most odd aspect is this is a little to no use gun that shows no signs of ever being worked on outside of the factory build. I don't mind replacing the part but it is hard to find and from what I have discovered from what is available are mostly used and expensive thumbpieces for this gun.