SMLE & Lee Enfield Bolt Heads

[bradtx]

delta8672, brewstop's response is dead on. The only thing I could add is that metallurgy, AFIK, is the same for all boltheads except those stamped 'M' or 'U', which I can't find my notes referencing the differences at the moment...it's a senior thing.

Brad

[Tom-May]

"...With regard to the steel specifications for these rifles is there any reference to the testings ?
The reference to the upgrade is quite common (Skennerton quotes EN grade and advanced heat treating for example) and I have previously seen mention of the testing that says it is no different. However these references have always been fairly brief and lacking detail..."

I'm afraid I don't know what further heat treatment the finished bolt head was given, but it you have the "EN" numbers I could let you know the basic data on the steel and its modern codes (well, to the late 1980s/early '90s) - I have an oldish copy of "Iron and Steel Specs" on my shelf.

Tom

[delta8672]

Greetings!

Am Back Again!

My SMLE No.I MK III Bolt has rust in/on its internal threads. Have tried a brass brush in a drill with Kroil, the great penetrating oil
with no luck.

Think that a correct size and thread machine bolt might chase the threads and remove the rust.

Can anyone please supply the correct thread specification for the Bolt/Bolt Head of the SMLE No.I MK.III?

Thanks in advance!

BlueSkies! delta8672

[Woftam]

Have look around this page. I'm sure it's there somewhere -
http://freespace.virgin.net/j.franklin/ ... -table.htm

[delta8672]

Greetings & Thanks Wolftam!

The link for "Threads used on Lee-Enfield Rifles" has the thread specification for the Bolt/Bolt Head. It is 0.4175" X 20 tpi.

That would appear to be a unique Enfield thread. 7/16 is 0.4375", so that would explain why a Bolt Head will screw into a 7/16 X 20 nut, but a 7/16 X 20 hex bolt will not screw into the SMLE Bolt.

I guess I shall have to try to remove the rust with a steel brush and Kroil.

The link on Lee-Enfield Threads, however, will be retained and cherished as great information. Again, Thank You Wolftam.

BlueSkies! Q

[Woftam]

Glad you found the information useful delta.
Most of the information is out there, its just a matter of finding it.

[Aughnanure]

Delta,

I missed this thread before; there are a number of ways of getting the rust out of the internal threads in the bolt.
The first and almost impossible is to use the correct Enfield tap.

Having got that out of the road, I'd suggest using a steel needle, a fairly robust one but one with a really sharp point.

The difficulty is to bend a needle to 90 deg.; if you have a gas burner that can be adjusted to a fine flame it is a simple matter to bend a needle. Decide on the length of bend, hold this part in a pair of pliers with wide jaws or in a vyce and quickly heat the needle next to the holding device. to red heat and bend. The mass of the holder should stop the point from loosing temper. If you don't have a burner then see your local friendly jeweller, he'll have a fine flame and even more importantly the skill; preferable to the local garage where they are likely to be a bit heavy handed.

Now attach a handle and start blindly scraping away at the rust. Araldite or a similar glue will hold it in a wooden handle particularly if the needle has a large eye.

Another solution is to get an old bolt head and grind it till there is a longitudinal groove along the thread, harden and stone to a sharp edge on the threads and screw it in thus cutting out the rust; if you do this make sure that you prepare the leading edge not the trailing one .

If you use a wire brush in a drill you'll wear the threads where there is no rust.