Sidelock bolts too short

[frogwalking]

I bought an old-stock but otherwise new kit for one of my grandsons, who likes to work on guns. It is a 12 gauge CVA double barrel. I decided to assemble the parts and convince myself that everything works and let him do hardware installation and all the finishing. (I have built many muzzle loaders, most from scratch, and none from this kind of kit.) Several problems have been found and fixed, but I am not familiar with metric screws. The locks have two sidelock screws holding them together, and in place in the stock. Both enter through the left lockplate pass through the stock and enter a pre-threaded hole in the right lockplate. The problem is that they are both too short with the locks fit into their mortises. It looks like the existing threaded holes are small enough for me to open them up with a drill bit and rethread for 8-32 screws, which I have on hand. I really don't know what size the metric screws are, so if any of you are familiar with this gun, perhaps you can tell me. I can then look up the rest. Thanks.

 

[Birddog6]

What makes the dif. what size they are If they are too short they are too short. Drill them out for 8-32, tap the holes & go on.

You could have been done while I typed this ! :idunno: :rotf:

Keith Lisle

 

[bpd303]

How well are the locks fit into their mortises? Do they meet the barrels? You may have to remove a little wood to seat them in more if there is a gap, then the screws would reach.

 

[Col. Batguano]

Percusion or flint?

Double flint guns are among the coolest of guns out there.

Not aware of any parts sets made by anyone.

 

[frogwalking]

Birddog, it makes a difference because the existing metric screws may be a little too large in diameter to leave enough steel to allow the holes to be drilled out and retapped to 8-32. If I knew the original screw size, I could look up the diameter of screw stock used to thread, and that would be the large size of the thread grooves in the lock plate. (major diameter?) It is much easier to screw something up than it is to fix the screw-up. Ask me how I know that.

 

[Semisane]

Why not just take the dang lock to a hardware store and try a bunch of different metric bolts to determine the size/thread count?

 

[Zonie]

The lockscrews on my CVA 12 guage double are M4 X 0.5mm flathead screws. They measures 1.668 (42.3mm) and 1.650 long.

These 4mm screws measure .154-.156 inches in diameter which makes them about .0096 smaller than a #8 screw.

The fine pitch #8 screw uses 36 threads per inch.
That would equate to a 0.7mm threads/inch metric size.

The bottom line is although a #8 tap could be run thru the hole, the thread pitch would wipe out most of the metric threads leaving very little material for the new #8-36 screws to grasp.

My first suggestion is to make sure the locks are fully seated in the stock and the hammers line up with the nipples. I suspect they both need to have their mortise depth increased just a little bit to get this hammer/nipple alignment correct.

Because the depth of both locks effect the length of the screws needed, just a little bit of added depth on each lock will have a lot of effect on the length of the screws.


My second suggestion is to try to find some M4 X 0.5mm thread flat head screws to replace the existing screws.

If you can't get any metric screws locally, give Deer Creek a call. They carry lots of CVA parts and they might have a M4 X 0.5mm screw in stock.

Deer Creek Products
6989 E Michigan Rd
Waldron, IN 46182

1-(765) 525-6181

 

[Birddog6]

It looks like the existing threaded holes are small enough for me to open them up with a drill bit and rethread for 8-32 screws, which I have on hand.

I was just going by what you stated. :idunno: You also need to insure the locks are Inlet fully.

Seems unusual they would furnish a kit & the screws be too short. Unless as someone pointed out you have not recessed the sideplate/washer to make it work correctly.

A call to Deer Creek could get you some longer screws possibly, if that solves the issue.

Keith Lisle

 

[Billnpatti]

If you have longer screws on hand that are slightly larger in diameter and will work, just drill out the holes, re-tap them and use the longer screws. If you want to stick with the metric screws, just take your lock plate to the nearest hardware store and start trying metric screws in it until you find the one that fits. They won't have lock bolts but you will then know the thread size and can order ther correct length from one of the muzzleloading parts places.

 

[frogwalking]

Thanks Zonie. It appears the answer I that the existing screws are too large a diameter to do what I was thinking. I think I can remove a small amount of wood from the plate inlet on each side without adversely affecting plate to barrel fit.

No offence intended, Birddog.

 

[Zonie]

I should mention that because the lock plates are not real thick where the screws go thru them, the factory screws are not real long. If they were, you would have to file off the end of them to keep them from sticking out of the right hand lockplate.

When they are at the correct length they are only screwed in about 5/64" (.078) from uninstalled to fully tightened.

That means if each of the lock mortises are increased a little more than 1/32 of an inch in depth, the screws will work fine.

Here's a picture of my CVA 12 guage double kit to give you some inspiration.



Oh. As I mentioned, the screws are M4 X .5mm which are the fine metric thread.
That's why I suggested using the fine thread UN thread.
A #8-32 has a metric pitch of 0.8mm making its thread pitch error 0.3mm. This is worse than the #8-36 thread with its 0.2mm error.

 

[Pete G]

Keep in mind that a kit is just an unassembled gun and the screws are the same as those on the finished gun. I would take a close look at the lock inlet before I started changing out parts.

 

[frogwalking]

Thanks guys. I sharpened up my little flat chisel (firmer?) and began slicing away the left lockplate inlet. I also had to file the standing breech down a little on the side, where the lock indexes against it. It looks like the right side will need the same treatment. Even after the provided bolts fit, I think the hammers may need to be tweeked to hit the nipples right. Zoni, how did yours fit? (Your gun looks great.) I also had to add about a quarter inch in height to the rear trigger to make it work. As delivered, when the rear trigger was all the way to the rear, it did not touch the sear bar.
The kit I have is absolutely nothing like an unassembled version of the finished gun. I have "assembled" a number of old Dixie kits back in the day, as well as several Chamber's kits, and this one is more difficult.

 

[Zonie]

I didn't have too many problems with the locks and triggers but it did take a bit of futzing around with them to get them to work right.

My chief problem with my (free) gun was it had been put together by a novice who did some whacking, some poor sanding and then some poor painting with varnish and a paint brush that left brush marks. He had left the stock unstained and IMO, unstained Beech wood is butt ugly.

The barrel had been left raw and 20-30 years of random rust on the outside had done some damage.

Stripping the crappy finish, sanding and then rust blacking the barrels, adding a TOTW steel checkered butt plate, adding a steel guide to keep the barrel aligned with the forestock, making new ramrod thimbols, fully sanding the stock wood, staining and refinishing the wood got it into pretty good condition.

Speaking of Beech wood and stains, do NOT use an oil based stain like Minwax. The wood will quickly load up with the oily stuff and refuse to become darker than a light medium brown with little unstained areas of hardwood showing thru.

Use an alcohol based stain like Birchwood Casey Walnut.

One of these days, I'll build a lined, wooden gun case for it, when the mood fits. :grin: