A couple of my first pipes have developed cracked shanks. One of them had a chunk crack away on top, the other one split down the middle on the bottom. I wanted slimmer pipes so on both of these I went from my usual 5/8 shank to 1/2 inch. The tenons are 5/16. I have an old Savinelli billiard that has a 1/2 inch shank and a 5/16 tenon and it seems quite sound. The difference is that my tenons on these early attempts ended up being about 3/8 inch long, whereas the Savinelli's is closer to 5/8 inch long. Is the extra length keeping more stress off of the end of the shank/mortise? Should I just graduate to skinnier tenons if I'm doing a skinnier shank? Thanks
Tim
Shank size and tenon length
Re: Shank size and tenon length
Beatus, what a longer tenon does is gives you more surface area between the tenon and the mortise walls. Basic physics equations apply here, and what it means is that if you want a tenon to "grip" you need a certain amount of friction. You can generate this by using a tenon 1/8" long and making it press the sides really hard (= cracked shank) or 1" long and hardly pressing the sides at all, for the same "feel". Obviously, niether of those makes any sense at all, but that's why you see a fairly long tenon where possible - it allows a tight feeling fit without applying pressure to the shank.
I've had pretty good luck on some fairly thing "Bing" style pipes with somewhat exaggerated tenon length - 3/4" or longer. They slide in easy, but park well, and don't exert much outward pressure on the shank.
I've had pretty good luck on some fairly thing "Bing" style pipes with somewhat exaggerated tenon length - 3/4" or longer. They slide in easy, but park well, and don't exert much outward pressure on the shank.
ALL YOUR PIPE ARE BELONG TO US!
Re: Shank size and tenon length
Thanks Sasquatch. Heh, the Savinelli in question is, in fact, a Bing's Favorite; ugly as sin, but it was free, so.....
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Re: Shank size and tenon length
For thinner shanks I've settled on a long 1/4" tenon. A 5/16" tenon seems too big for thinner shanks without banding of some kind.
Re: Shank size and tenon length
Yeah, I think I'm going to order a bigger variety of sizes of Delrin from Mcmaster this time around....give me some more elbow room for customifying my tenons.KurtHuhn wrote:For thinner shanks I've settled on a long 1/4" tenon. A 5/16" tenon seems too big for thinner shanks without banding of some kind.