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268102 Ed Minch <ruby1638@a...> 2019‑03‑13 Dowel plate
Did a fun thing today

On the big big Kalmar Nyckel, trunnels are used for fastenings in many places,
mostly planks on the hull and deck into the framing underneath.  A trunnel is a
wooden dowel that has a slot in both ends.  You put a wedge in one end and drive
it wedge first into a flat bottomed hole.  As it bottoms out, the wedge spreads
the trunnel and locks it in place.  You then drive a wedge into the top.  So the
trunnel is wedged in place at the top and the bottom and acts as a bolt.

The biggest we use is 1-1/4” and driving them into existing holes that old ones
have been taken out of has always been a hassle.  I made a chair devil with a
round recess in the blade that matches the biggest trunnel, and that has worked
well, but I thought that a dowel plate would be faster.  The question in my mind
was could you drive something that big made of Jatoba, a very hard wood, without
crushing the wood or wearing yourself out.  Also, the local machine shop wanted
$200 and another $175 to heat  treat it.

One of the other volunteers is a machinist and he made one to my specs with
1/64” steps either side of 1-1/4”.  I turned up a couple of Jatoba blanks just
big of 1-1/4" and we had at (past tense of "have at’).  Here is a picture:

https://www.flickr.com/photos/ruby1638/46456769695/in/dateposted-public/

It did a passable job with reasonable effort - actually once it was sized at the
biggest hole, the 1/64” steps were fairly easy.  But you could see a ring at the
start of each blow that was a little off of the finish of the travel of that
blow.  Then my machinist mate had an idea - we stuck one in the 20 ton press and
shoved it smoothly through and it it made a beautiful thing.  Just the hint of a
bow along it’s 7” length, but good enough for shipbuilding.  So now we can make
our own accurate trunnels without a drawknife and shave horse, but still be
galootish.

How cool is that

Ed Minch
268103 Dragon List <dragon01list@g...> 2019‑03‑13 Re: Dowel plate
On Wed, Mar 13, 2019 at 2:29 PM Ed Minch  wrote:

> Did a fun thing today
>
[snipped per faq

> How cool is that


very, very.

thanks, ed.  love to see what you do!
bill
felton, ca
268107 Claudio DeLorenzi <claudio@d...> 2019‑03‑14 Re: Dowel plate
Great story.  How did you prevent the dowel stock from popping out sideways
when pressing it through the plate? Even when doing manually with a mallet,
some of my dowels come out wonky, and I’ve never made any of that size
(impressive!)
Cheers from Waterloo
Claudio

Ed said:
How cool is that?
Ed Minch
268108 Ed Minch <ruby1638@a...> 2019‑03‑14 Re: Dowel plate
Not sure what you mean by “popping out sideways”.  Driving with a hammer, they
went right in, but I had to be careful to drive it straight. It was easy to
bring back to plumb, but easy to get out of plumb a little.  That is what leaves
a bit of a wonky surface on the wood.  Also, the hammered ones had more of a bow
along the length, but once we pressed them through smoothly, they look great.

Ed

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