Washers, dieseling, size of transfer ports and similar matters

[andrewM]

Looking at the internet, I discovered this link, this evening, although I cannot recall the source; it might even have been from the BBS.

https://www.pressreader.com/uk/airgu...82321090250316

The gist of it reveals that changing from a leather seal (not sure if this is interchangeable with the word 'washer', ie one and the same thing) to a synthetic seal would create a need to reduce in diameter the size of the transfer port - quite a technical operation. Moreover, airgun manufacturers expected their products to diesel and factored in a degree of this to create the necessary velocity. This rise in the velocity from the use of oil was, I suppose, obvious given that instruction manuals requested the insert of so many drops every 500 pellets. This set me thinking; given that neatsfoot oil compound does not diesel, or at least it does so at higher temperatures, I wondered if its use would defeat the object of using an oil. I wonder what technical experts, here, think?

In any event, swapping a leather seal/washer for a synthetic variety might not be such a good idea unless the transfer port is modified. This sounds like another exam question, were it to be followed by the word 'discuss'!

[T 20]

The article was written by our very own Mr Jim Tyler, who is BBS member and Administrator, BTDT.




All the best Mick

[andrewM]

The article was written by our very own Mr Jim Tyler, who is BBS member and Administrator, BTDT.




All the best Mick

Thanks for that, Mick. I have heard of the impressive technical abilities of BTDT, no less from Protek, who are themselves competent airgunsmiths.

Whilst my technical abilities in the engineering department hover a little above zero, I find the theory fascinating, so this was for me an interesting article.

Am I correct, I wonder, on the use of neatsfoot compound for leather washers if its dieseling qualities are somewhat less than for other oils? BTDT also says that neatsfoot oxidises and hardens the leather. Perhaps the answer is to vary the oil, using neatsfoot sometimes and another appropriate oil on other occasions. It seems everyone here has their own view on the oil to use and there seems to be no unanimity of opinion, with some collectors even using 3 in 1.

[Phil Russell]

I cannot doubt Jim but I believe that there are several 'blends' / varieties of neatsfoot oil and I wonder if some are better than others.
To date I have had no problems using neatsfoot for soaking new leather washers in when I have been making them for a few old rifles.
Cheers, Phil