Converting a J frame Coil Spring to Flat Spring

StrawHat · Jul 18, 2023

I have searched this area and the whole forum. Not luck but I remember reading about the conversion.

Does anyone have a link or remember how it was done?

Thank you.

Kevin

ken158 · Jul 18, 2023

No idea how that could be possible with the differences in engineering - but of course, someone will say enough money will make anything possible.

robertrwalsh · Jul 18, 2023

Pretty much anything of a purely technical nature can be done if you are willing to spend a ton of money on it but I don't remember ever seeing anything in print about it and I have been following the "gun press" reasonably closely for over 50 years. A second question would be WHY, but I suppose I WANT TO is an adequate response to that. Happy research.

colt_saa · Jul 18, 2023

StrawHat,
I also do not recall an article on this subject

Now I have seen article for the opposite conversion . . . K, L and N frames to utilize coil main springs

I have handled two or three K-frame PPC revolvers set up with a coil mainspring, but I can not recall who built them, this was decades ago

Protocall_Design · Jul 18, 2023

TKCustom recently came out with an N frame conversion to coil spring. I don't know what the advantage of it might be over the original leaf spring version.

chief38 · Jul 18, 2023

I don't know if there is enough room in the grip frame of a J frame Revolver to do that. The real question is WHY? They have been making J frames and I frames before J's with coil springs for decades. Seems to work just fine. Why mess with success?

Bullet Bob · Jul 18, 2023

"I don't know what the advantage of it might be over the original leaf spring version."

Money in their pocket?

StrawHat · Jul 18, 2023

colt_saa said:
StrawHat,
I also do not recall an article on this subject

Now I have seen article for the opposite conversion . . . K, L and N frames to utilize coil main springs

I have handled two or three K-frame PPC revolvers set up with a coil mainspring, but I can not recall who built them, this was decades ago

Travis Strahan did the PPC revolvers with coil mainsprings. They were interesting but I did not like the trigger action.

Kevin

StrawHat · Jul 18, 2023

chief38 said:
I don't know if there is enough room in the grip frame of a J frame Revolver to do that. The real question is WHY? They have been making J frames and I frames before J's with coil springs for decades. Seems to work just fine. Why mess with success?

The factory used flat springs in the I frame and the M frame. The “big news” with the Chiefs Special was the use of the coil spring.

Why? Have you ever used a well tuned revolver? Coiled mainspring are not even close.

Kevin

chief38 · Jul 18, 2023

In any hobby there will always be a few that buck the tide and feel compelled to just be different. I am NOT judging here. Sometimes people just want to be unique. If they can afford it, get a thrill out of it and they enjoy it - why not!

NYlakesider · Jul 19, 2023

chief38 said:
In any hobby there will always be a few that buck the tide and feel compelled to just be different. I am NOT judging here. Sometimes people just want to be unique. If they can afford it, get a thrill out of it and they enjoy it - why not!

It does make a good talking point!

gwpercle · Jul 19, 2023

You probably saw some "fake" U-tude expert doing the impossible .

They used to fool me but I was shown the difference between "real world" doing something (picking a lock by a professional locksmith with lock picking tools ) and U-tube fake lock picking (with a bent paper clip ) The locksmith proved the "fake" U-tube lock couldn't have had any tumblers in it .

They will show anything on U-tube real or imagined .

The conversion you suggest would not be practical ... too much refabrication of the frame and lockwork would be required .

Gary

StrawHat · Jul 19, 2023

gwpercle said:
You probably saw some "fake" U-tude expert doing the impossible …

The conversion you suggest would not be practical ... too much refabrication of the frame and lockwork would be required .

Gary

Gary,

No, not u-tube, I do not watch any of them.

I have the 32 Hand Ejector on the I frame and a Model 36-1. The action on the I frame is so much smoother that the Model 36-1, or any Model 36 I have used, that I want to say it has to be the mainspring.

Kevin

Green Frog · Jul 19, 2023

Kevin,
I thought I had replied to this a day or two ago… but my answer disappeared into a cloud of electrons.

I believe there is plenty of steel in the grip frame of a pre-lock J frame. In addition you will need to acquire a leaf spring and strain screw as well as a hammer assembly from an original I frame. The hammer block from the J frame may also need to be allowed for.
I would first take off the grips from both my donor J frame and a model I frame to serve as a template. You’ll have to hog out a bunch of steel from the J frame. Then, if that looked like it would work, I’d gather up the I frame spring and hammer parts and check about compatibility before I made my first cut. If you get that fat, I may be able to help you with some of the parts.
Your Phriendly’Phibian

paladin42 · Jul 19, 2023

I'm not sure what the fuss is about doing a conversion to a leaf spring. I've tuned many J-frames and the trick is to just use the correct main spring. Cutting off coils on the "standard" main spring just won't do the trick. Look into using variable tension main springs that don't "stack".

Hondo44 · Jul 23, 2023

StrawHat said:
I have searched this area and the whole forum. Not luck but I remember reading about the conversion.

Does anyone have a link or remember how it was done?

Thank you.

Kevin

Kevin, There is a thread about this. It’s been a few years and when I get home to my computer I’ll pull up my notes. Green Frog and I have long bemoaned the change from leaf spring to coil spring about 1950, in our I frames. So it caused me to figure out how to do it and post it. It’s a fairly simple process and he already listed the replacement parts from a pre ‘50 I frame needed which are not hard to find. I and J frame hammers are interchangeable. And as I recall the stirrup for the leaf spring to hammer connection can even be installed in the J Frame hammer by drilling the retaining pin hole to save the cost of a replacement hammer. A Dremel tool is the way (unless you have a milling machine of course) to remove excess metal in the grip frame and to shape it like an I frame made for the leaf spring. A jig saw will easily cut the slot for mounting the bottom end of the leaf spring. Lastly drill, tap and counter bore the hole for the spring tension screw in the front lower grip strap.

I’m going by memory here but I’ll post my process when I get home.

Hondo44 · Jul 24, 2023

CONVERT I AND J FRAME COIL SPRING TO I FRAME LEAF SPRING

Here's what to do:
A round butt J frame is much easier to convert to a leaf spring.

Photo 'A': Coil spring:

Photo credit: handejector

Photo 'B': Leaf spring:

handejector-albums-early-38-regulation-police-picture9541-014.jpg

STEP ONE: Secure a hammer w/toggle leaf spring mount, shown below, (or drill the hammer for the toggle and pin), leaf spring, and spring tension screw from a post WW II "Transitional" I frame (still uses the leaf spring). Rimfire .22/32 Kit Gun hammers must be converted to retain the wide spur target hammer; just requires drilling the hammer for the toggle and pin, and reshaping the bottom a bit. Can also be done on the center fire hammers.

STEP TWO: Remove coil spring and swap hammers.

STEP THREE: Using a jig saw or coping saw with metal cutting blades, cut out the coil spring mount from grip frame shown in 'A' above.

STEP FOUR: Drill the hole for the bottom end of the leaf spring at the location shown in 'B' above. Cut the slot connecting the hole to the open space.

STEP FIVE: Drill, tap, and countersink the hole for the spring tension screw. Install spring and screw and there you have it!

Parts are available on ebay and gunbroker; search for a pre IMPROVED I frame (pre 1952) parts kit.
NOTE: Parts from a pre war I frame with the trigger rebound slide (post ~ 1915) are more numerous, easier to find, and useable but the hammer will need a 'flat' filed in the face below the firing pin to work with the post war frame which has the sliding bar hammer block safety.

Mike SC Hunter · Jul 24, 2023

And take a giant step backwards.

StrawHat · Jul 24, 2023

Mike said:
And take a giant step backwards.

How so? I have yet to find a Model 36 with as smooth an action as a K, N or even and L frame, from the box. Even after having an “action job” they are still in second place behind the leaf spring.

I guess I am like those who bellyache about the storage lock, the lack of barrel pins, non recessed chambers on Magnums and a laundry list of other changes that others accept because they come from the factory and the factory knows what is best?

Seriously, the nice thing about being where I am in life is I can indulge myself a little. I have a Model 36-1 and a 32 Hand Ejector. The action is like comparing apples and quince. I like apples.

Kevin

tmd17 · Jul 25, 2023

I love these sorts of threads, and am always amazed at the work home smiths do. Without the questions and willingness to try, we would all be throwing rocks.

Instead, we launch very carefully crafted projectiles from hand held rocket launchers.

Converting a J frame Coil Spring to Flat Spring

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