What's up with the 3rd Gen sideplate assembly?

Got around to replacing the S&W grips with the Hogue grips on a 4586. The left grip required quite a bit more wrestle time to fit, probably because of the sideplate assembly. Yes, I followed directions. The sideplate assembly has that forked end that the pin goes through, then the grip has to fit over this . Very easy to bend the fork and loosen it from the pin.

What a really bad design. What were they thinking? Drive a pin out to remove the grips, and be careful and don't bend the sideplate assembly when removing and installing the grips. Gotta place the mainspring in its cup and put it into the grip when installing grips, because the mainspring is held by the grip, etc... Hogue improves upon this mainspring mounting a bit though.

I'm thinking that every time I want to remove the grips to clean the gun, I will stress the forked end of the sideplate assembly.

I'm not a hater of the 3rd gen, I love the rest of the design. They are well made.

One of the Bud's police trade in 4586 we received will need a sideplate assembly for sure. The pin won't keep the assembly fixed since the fork is bent.

I don't think they were thinking about Hogue's grips.
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I have never had a problem with the sideplate and the grips and I only use the factory grips. I wonder what is happening.

With the Hogue there shouldn't be any problems because they are two piece, clip into the front, and screw into the adapter that holds the mainspring.

The current side plate assembly is much improved over the earlier post design used to tension the slide stop lever plunger in the earlier generation guns.

The trick to replacing the factory grips without damaging the side plate is simply (and unavoidably) some basic knowledge, familiarity and experience with the process.

Replacing the factory grips involves having to pay attention to different things, such as the orientation of the hammer spring cup and the hammer stirrup, clearing the frame windows with the grips recessed hooks, making sure the rear of the grip is pushed fully forward under the frame tang ... and making sure the left/upper part of the grip clears the side plate.

Typically, from what I've seen, the side plate may become tweaked and damaged when the left/front corner of the left grip panel becomes caught either under the edge of the side plate's upper arm, or under the small angled plate located at the front of the side plate (end of the arm), when someone is trying to position and shove the grips on.

A moment's distraction from how the left/upper part of the grip is slipped over and around the side plate and it's angled end, making sure the grip doesn't catch and snag on the side plate, should be avoided. Too much pressure on the top edge or the small angled plate which sticks out from the frame can stress (via leverage) the rear leg of the 'prongs' which seat around the recessed head of the sear pin.

Also, sometimes when an armorer seats the prongs around sear pin, the wrong pressure applied (unevenly) can tweak one or the other prong and cause them to be uneven, making it more difficult to get them evenly snapped into position and both supported by the sear pin. In bad circumstances, with excessive force being unintentionally applied in the wrong way, one of them can even break and snap off.

When I reinstall the side plate I like to place the right side of the frame on a nylon armorer's block (to support the sear pin), and then use the edge of an armorer's wooden wedge to gently and evenly press down on both prongs to snap them over and around the head of the pin (with the wedge pushing down on the prongs close to the pin).

If the side plate is tweaked and the prongs bent, or one broken off, the side plate won't be properly anchored, which means the front of the side plate which rests against the slide stop lever's plunger won't be held immobile. This can result in the slide stop shifting when it shouldn't, possibly not being held down under recoil, or having the plunger slip under the small plate and becoming trapped, unable to rise upward. Functioning problems can occur.

Installing the side plate means having to know how to disassemble/reassemble the frame so the hammer and 3 levers are positioned properly. In the standard 3rd gen models this means knowing how to align the ejector and hammer, and then the sear release lever and the firing pin safety lever on the right side of the hammer. Usually most new armorers have to use the end of a pin punch to align those 2 levers on the right side of the hammer so the side plate pin can be inserted through them, but it's possible to learn how to hold them together as a pair and manipulate/position them down into the frame slot and past the itty bitty lever spring (without snagging it and launching off and away ) to allow the side plate pin to pass through them. It does take practice.

The side plate for the 10mm guns is different than the one sometimes used in one of the earlier .45's, BTW. I'm told the angled plate at the front of the side plate has a different angle needed to hold the slide stop lever down under the heavier recoil of the 10mm. The one used as a revision in the 4506, and later model .45's, is the same as that used in the 1006/66. Perhaps they upgraded the ones used in later model .45's.

I spoke with S&W parts, since we need the sideplate assembly for one of the 4586s we received. That one came from Buds with a bent fork end sideplate assembly, and it was off of the sear pin when we removed the factory grips. Luckily, my 4586 is fine after I got the Hogue grips on.

Confusing part number system they have. S&W says that the 4506-1 and the 1006 use the same frame, and the correct part is 108600000 Revision 1. Their PDF lists a part 106990000 for the 4586. They list two part numbers for the 4506: 108600000 Revision 1, and the 106990000. I know the early 4506 had the smaller frame than the 4506-1
I would think the 4586 would use the exact same Revision part as the 4506-1, the 108600000. Don't they have the same frames?

Now, I want a spare sideplate assembly for my 4506-1, and one for my 4586. The parts are cheap, and shipping is almost a flat fee anyway. Can anyone confirm what part numbers are need for a 4506-1 and a 4586? S&W parts was a bit hesitant when I asked. Thanks for the help

The sideplate assemblies (the being pin staked into the plate makes it an assembly) can be confusing at times since there's been some revisions. Also, the online parts list on the website isn't always as up to date as the in-house parts listings the customer service reps can access, and even they don't always list the latest changes that the engineers might have developed (which take time to get put into the parts listings). I've had that happen a few times when calling back to confirm part numbers, only to be told I actually needed a brand new revision part which hadn't been entered into their computers.

Then, there's going to be different part numbers reflected when the sideplates are made of carbon steel instead of stainless for some models (like the 4505 and the early blued CS45's, for example).

The 4506 has a couple of sideplates listed, one being a revision (R1; #10860), and which matches the side plate used in the 1006/1066. Just looking at the parts list, the older standard sideplate for the 4506 (#10699) is not the same one used in the current 45XX guns (#10860), but it is the same one used in the 1086.

So, while I've been told that the older 10mm guns needed a slightly different angle to their plate which engages the slide stop lever plunger, perhaps they've decided they could start sharing the parts witth the .45's (or vice versa), except for the 1086 ... and even then I'd call and confirm the appropriate part number before ordering something, since you never know when the engineers might have decided a change was appropriate.

I was sent a #10699 sideplate one time for a 4566 repair, and when I saw the number didn't match the part list I had at hand I called to check on it. They checked and told me I really needed the #10860 sideplate ... and yet the #10699 sideplate is listed as the original standard sideplate for the 4506, before the R1 #10860 part. Go figure. They sent me the #10860 part right away.

That's why I always call and check the part numbers I think I need against their current computer listings, just to make sure I really want what I think I want, and that a revision hasn't occurred which I should use.

That's also why I don't bother to memorize any part numbers. It's easier, and more accurate, to call them to confirm.

Question from someone not that familiar with all the inner workings of the guns.
What is the result of a damaged side plate assembly? And how would you know if you have damaged it while changing grips? Or what would you look for when considering buying a used gun?
Thanks for all the info!

GJH77 said:

Question from someone not that familiar with all the inner workings of the guns.
What is the result of a damaged side plate assembly? And how would you know if you have damaged it while changing grips? Or what would you look for when considering buying a used gun?
Thanks for all the info!

Click to expand...

I think Fastbolt says it best:
"Typically, from what I've seen, the side plate may become tweaked and damaged when the left/front corner of the left grip panel becomes caught either under the edge of the side plate's upper arm, or under the small angled plate located at the front of the side plate (end of the arm), when someone is trying to position and shove the grips on"

One of the used 4586s that we ordered came this way. The slide stop had play in it due to the sideplate assembly coming off of the sear pin. The sideplate would move, and you could see it move easily with the grips on. I won't say it happens all of the time, since plenty of 3rd gen owners say they never had a problem. Most of the time, it will be related to putting a grip on wrong.

Here is a diagram I made up to illustrate the situation.

I always wondered what the whole "little plunger that rubs against the bent sheet metal thing" on the S&W semiautos was all about. I haven't taken the grips off of my 4586 yet, but I did look underneath one side and there's a lot of crud, but no rust. I think I'm going to put a set of Houge grips on it soon, and your diagram will help me out. Thanks.

Here's my police trade in Bessie. Gussied up with the Hogue grips.

GJH77 said:

Question from someone not that familiar with all the inner workings of the guns.
What is the result of a damaged side plate assembly? And how would you know if you have damaged it while changing grips? Or what would you look for when considering buying a used gun?
Thanks for all the info!

Click to expand...

If the side plate isn't held stationary, the small angled plate at the front which engages the slide stop lever's plunger won't be held at the same required angle to tension the plunger to the degree intended. If the plate can shift upward ... like when the rear prong/leg of the side plate is bent, spread or broken off ... then the slide stop lever may also lift under recoil and be able to lock the slide back early, when ammunition remains in the magazine. The lever's plunger might also shift downward and become trapped below the bottom edge of the small angled plate, too.

The stability of the side plate can be checked by gently grasping the small angled plate (exposed above the grip) between a thumb and finger and applying gentle pressure to see if it can be wiggled up & down easily. It should remain firmly fixed and stationary. The key is to use gentle force to check it, meaning don't crank on it and end up causing the very type of damage you're checking to make sure hasn't occurred.

Once the grips are off, the snugness of the prongs snapped around the recessed head of the left end of the sear pin can be visually checked, too. Sometimes when someone tweaks the prongs, if the rear one is bent out & away from the frame far enough that it won't engage under the pin's head and remain there, the sideplate may become just as unstable as if the prong leg was spread apart or broken, not being able to secure the bottom of the sideplate to the sear pin.

I've found it's often easier to avoid damaging the side plate when installing the Hogue grips, because of how they're slid forward instead of being rotated upward. Making sure the tall recessed hooks align with the frame windows on each side of the grip frame, and having the small recessed hooks align over the narrow part of the frame to each side of the mainspring, is important when installing the Hogue grips. So is remembering to replace the factory grip pin (which I've seen people forget to use when installing Hogues).

Also, it's still important to make sure the grip fits up snug under the frame grip tang, with both factory & Hogue grips, so the grips slip far enough forward. This is especially important on the TDA guns which have a decocker lever, because if the grips are fully forward the decock lever might bottom out against the grip's top edge before the hammer is decocked. Here's some pictures showing proper & improperly seat factory grips where the decocking lever has proper clearance, and then is blocked. It's usually easy enough to complete seating of the factory grips by grasping them normally and squeezing, which usually causes the grips to move forward the last bit of required distance under the tang.

Properly installed:



Improperly installed:

Do I have a problem?

Wow, Great explanation and pictures. Thank you.
This thread attraced my attention because I noticed while cleaning my 4566 last weekend that the angled plate had moved, as it bumped the slide when I put the slide back on. I wondered why, as I had not noticed it before, but did not pay it too much notice. Then this thread question comes along and I really wonder what is up. I put these Hogues on soon after I got the gun, and had no problem doing so, thanks to the advice found on the forum, and they appear to be installed correctly. The gun has shot fine and operated perfectly multiple times since then.
So I pulled the grips off this afternoon, and the sear is positioned in the side plate prongs, but it is not tight. The rear prong appears to be slightly bent out of parallel to the front prong. Sorry for the poor photo, that is as good a resolution as I could get.
So my question- is this slight spread a problem?
If so, from your description of installation, this sounds like it is not something I should attempt to replace, but does it need to go back to S & W and is it a warranty item?
Interestingly, I recently bought a 6946, and had a problem with the slide randomly not locking back every time a mag was emptied. That sideplate assembly appeared to flex out from the frame, and I wondered whether that flex was the problem. It is currently with LSG being corrected, but I do not know the reason for the problem yet.
As always, you guys are a wealth of information and help, so thanks again.

If it were a duty/carry gun and the rear side plate legs were spread like that, I'd replace the sideplate. Both legs should snap around the head of the sear pin and hold it secure.

Here's a sideplate properly secured over the head of the sear pin.

Sorry to resurrect an older thread, but I have a question about the sideplate and sear pin, and this thread has great pictures.

I replaced the straight grips on my Bud's 4586 this afternoon with 4506 curved backstrap grips, and spent some headscratching time looking at the sideplate and the prongs. The prongs were off the sear pin when I removed the original grips, but I may have dislodged it accidently. I remembered from reading this thread that it was important to get the ears around the sear pin, but it was very difficult to get them to stay inplace. The ears are not bent, but there doesn't seem to be any retaining groove or indent on the sear pin to hold them in place. the sear pin barely extends from the frame to about the thickness of the ears.

Is there supposed to be some recess or groove to hold the sideplate ears? Perhaps the sear pin is in backwards?

I eventually got the sideplate to stay in place while replacing the grips, and everything is together and in the proper place.

The exercise was worth it - the gun feels much better in the hand and points much more naturally, much like my favorite M39s. Off to the range tomorrow to find out how it feels in action.

Yes, there is a recessed machined groove on the left end of the sear pin. The prongs of the sideplate snap around the left end of the sear pin inside this groove.

Here's a picture of the head, or the left end, of some used sear pins (which is why they appear a bit worn):


Here's a picture of a sear pin positioned within the prongs of a sideplate for illustration (as if both were installed in a frame):


Here's a picture of a sideplate just before the prongs are pressed down and snapped over the head of the pin:


And after the prongs have been snapped over the head:


There are different length sear pins for the different width frames.

The pin should be just long enough for the right side of the pin to be approx flush with the right side of the frame, but with the left (headed) end sticking out just far enough for the sideplate prongs to fit over the end of the pin, within the recessed groove in the head of the pin.

In the pictures where the sideplate is installed in the frame (in the above couple of pictures and the one in the previous posting), the right side of the frame is resting flat on a nylon armorer's block, which is keeping the sear pin flush with the right side of the frame. You can sort of see how much of the pin is sticking up above the left side of the frame once the slideplate's prongs have been installed over the head of the pin.

Without seeing the specific gun and sear pin, there's no way to know if someone had reversed the orientation of the correct pin, or used the wrong pin.

Thanks, Fastbolt, that helps a lot.

The sear pin was extending beyond the frame about an equal amount on either side, so now I need to go back and carefully move it a bit toward the left to see if the groove appears. Hopefully it's installed in the correct orientation.

I'm pretty handy with small complicated mechanical pieces and things that go "sproing" since my other hobby is watch and clock repair, but I proceed carefully when I haven't seen a particular mechanism.

Might be that someone removed the sideplate and didn't reinstall it over the sear pin correctly. It's not supposed to be 'even' on both sides. The left side sticks out farther so the sideplate can be secured over the left end (head) of the pin. If the sear pin has been reversed, care must be taken to make sure the sear remains correctly positioned in the frame. The bottom of the sear must be against the front of the top of the sear spring (not against the back side of the spring). If it slips forward away from the spring the top of the sear can become caught out of position.

In the armorer classes they usually show how the sear pin can be held under the sideplate prongs, flush on the left side, held in position with a thumb, while the broad butt of the handle of a pin punch is used to push against the extended right end of the pin, pushing it through the prongs until the head snaps up between them and captures the prongs in the groove. I've seen the prongs become uneven, tweaked and bent. It's even possible to break on prong off if it's not done properly and with due attention.

I sit the frame on its right side on the block (or other flat surface) so the right end of the pin is even with the right side of the frame. That makes the left end of the sear pin stick up clear of the left side of the frame. With the sideplate resting just above the head of the pin, I use the end of the wooden armorer's wedge (or sometimes the square wooden handle of a cleaning brush), held close to the spot where the pin is located (like in the pictures) to evenly and gently but briskly snap the prongs down over the head of the pin, completely seating the sideplate. I've found it's easier to avoid applying uneven pressure against the prongs this way, but that's just me.

Naturally, I don't recommend anyone attempt to 'work' on any guns unless they're familiar with what they're doing. I've certainly seen sears & sear pins installed incorrectly even by armorers, though. (Disclaimer done.) There's no way I'd attempt clock repair.

Feel free to use my email if you have any 'educational curiosity' questions.

BTW, anchoring the side plate over the sear pin head is important because it provides stability for the slide stop lever. The small angled plate at the front of the sideplate provides the proper angle needed for the slide stop lever's plunger to let the slide stop lever act as intended. A loose sideplate can allow the lever to slip upward under recoil too soon, creating the potential for an 'early slide stop' condition (where the slide is locked back with rounds remaining in the mag), or even shift and trap the slide stop lever's plunger under the plate.

Good luck getting a sideplate assembly, I have had one on back order for a 4003 for 4 months.

Everything is good!

With the help of the pictures, everything went together as it should, no damage.

This forum is a great resource.