This post is detailing a conversion I did on an NHM chu wood thumb-hole butt stock.
I wanted a longer chu wood stock, as the original Chinese butt stocks are too short.
Conversion started with a stock that was originally on an NHM-91.
I started with the top stock in the pic.


Comparison to line up.


I chopped to PG portion off, lost a bunch of pics when Windows 10 updated, but started with this, and some work with the wood file.


I had an extra EG smooth butt plate I was going to use.


There was a lot of side by side comparison to get the contour right.


The NHM stock was about 1 1/2" longer, so perfect for the conversion.


I pretty much filed off anything that didn't look like it belonged....


Lots of sanding later....




I plugged the original sling swivel holes with some dowels I made out of some chu wood removed early on.


Probably the hardest part was filing the rear portion to accommodate the sloped EG butt plate. This was done by hand, file and sand paper.


Inletting the rear for the butt plate.
I used a Dremel, hand file and sand paper.


Test fit.


Compared the sling swivel on another thumb-hole stock and used it as a pattern for the conversion.


Bore bit to remove material.




One coat of Iodine.



3 coats of shellac.




Fitted onto a rifle.



The stock needs about another 1/8" removed from the bottom as it's a little "thick" compared to preban stocks, but all in all, it turned out a lot nicer as far as length of pull is concerned, and matches original parts finish pretty well.

Wow, great job!

Very nice work. I like how it looks so very close to original but longer. How long did it take to complete?

Took all in all about 6 hours to finish.

God dammit I gave my thumb hole set away!!! I never thought of doing this!! Looks awesome!

Very nice job!!

Awesome job!  Thanks for sharing

Awesome! Good job!

Wow

Updated with the pics I could find.
I used an original stock for the pattern. Scribe a line with a magic marker, then chop off everything else.
Attached File

Lot's of hand filing with a coarse file.
Attached File

More filing.
Attached File

this is using the original to judge the profile of the wrist of the stock. More filing.
Attached File

Lots of sanding. Several pics between this and the last got trashed.
Attached File

Comparing profile.
Attached File

This area needs to be thinned to match the profile of the original.
Attached File

Screw holes from the NHM sling swivel need filling.
Attached File

I made a couple dowels out of scrap then glued in. After dry, cut and sand what remained.
Attached File

Attached File