dovetail jigs

[ljmathias]

Just got an update from Timberwolf tools and they are advertising a jig set for big timbers that lets you make both the male and female parts of a dovetail pretty fast (at least the video looks pretty fast, but then that would be a marketing tool: http://timberwolftools.com/tools/arunda/arunda.html).  Problem is price: $3-4000 per set (yes, that's thousands of dollars).  So question is: does any one out there have them, and are they worth it?  I can see lots of uses, from floor joists to rafters to purlins to furniture, but the price!

Related question: given that the dovetails look to be a couple inches max in depth, would these work on green timbers?  I'd think shrinkage would be pretty high, making the joints pretty loose after a couple years: thickness shrinkage in the male end would let it slide out some.  This might be compensated some by shrinkage of the female end (in the side of a beam, say) that would pull against the joist trying to slide out.  Problem might be then that the bottom of the joint has less area to set on.  Probably not making myself clear, but there has been some discussion in the past of dovetails versus a tusk joint, especially a housed tusk.  Thoughts anyone?

So two questions, really: are the jigs worth it (30-60 dovetails in a days work maybe) and are dovetails long-term functional??

Lj

[Jim_Rogers]

does any one out there have them, and are they worth it? 

As far as does any one out there have these, I'd have to say that probably only big timber frame companies would be able to afford them and use them regularly. I wouldn't see the average timber framer who uses this site being someone who would own a tool like this.

given that the dovetails look to be a couple inches max in depth, would these work on green timbers?

The seemed to be using them on green timbers in the video, but your point about the shrinkage is a valid one.

are dovetails long-term functional??

That is the question. This is something that probably should be posed to the manufacturer and ask them to show us the first dovetails done with the system when it was invented and let us see how much they have shrank over the years since they were installed.

Timberwolf tools is a distributer of this tool, which looks to be made in Europe, and we could ask them to provide some testimonials from a satisfied customer, from the USA, who has used them for some time and let us see if they are something good or not.....

Those are my thoughts on the subject....

Jim Rogers

[Larry]

Minus the engraving, it would be a two hour job making the aluminum jigs.

Order your custom made router bit from these folks.

http://www.wdr-sales.com/routerbit.htm

There good people.

Can't say how it would work, just thought I would give my thoughts on how to save a bit.

[addicted]

In the spring I took a tour of two TF companies. Both used the large Hundigger machine for most of the joinery. They used a lot of the short stub tenons in their design followed by a couple of big screws that would be covered by flooring later.  I would assume that this dovetail jig allows one to raise the frame with the convenience of having dovetails( ie raise two bents and drop in a few joists allowing the dove tail portions to hold the two bents for a short time until all joists/summer beams/girts etc.. are in then start screwing) and the same benefit of stub tenons. Shorter timbers, machinability, shallow mortises.
This is just a wag. I am by no means an authority on the subject since I'm just starting to learn about this great craft.
Rusty

[ARKANSAWYER]

  You can buy the router bit and make a guide from 1/4 plywood to do the same thing for less then $100.  I would also not do the dovetail in green timbers.  Old reclaim stuff or dried wood would be a different thing  but the green timbers would not be a good choice.  Once you had a good plywood jig a CNC plasma cutter could make you some metal ones pretty fast and cheap.  Not sure why they want so much for theirs.

[ljmathias]

Thanks, all.  yeah, I thought about making some jigs out of plywood or aluminum sheet metal- easy enough with plywood to make a set for each size beam.  Still comes back to question of long term stability of the joints.  I can sure envision wacking out a bunch of joints in a day, making a flooring system fast to make and put in.  Not so sure about the roof system they talk about- you'd have to design it so the rafters had the same angle on both ends (parallel) to be able to slide them in place.  The purlins would be easy, though, and just dropping them in to tie everything together would be great- plus give a nice flat set of beam and joist surfaces to lay decking onto...

Guess I'm just getting frustrated with getting my workshop built, or rather, not getting it built.  Had a TF workshop (educational kind) here a couple years ago and roughed out some bents but never got it built and I just can't seem to find the month or so of continuous free time (is any time ever 'free?') to re-do and clean up the bents plus make all the other pieces... Got too many irons in the fire (and what does that mean, anyway? branding irons? brand cattle with the wrong iron?)... :-\

Oh, well, back to cutting dimension wood for the son's house tomorrow, if it stays cool, which it won't, so I'll do what I can till I run out of hydration than sit for a while to re-hydrate and come to my senses, as if I ever had any...

Lj

[Hilltop366]

The welding shops around here use a lot of aluminum on fishing boats, I have seen them do straight cuts with a regular skill saw with a good carbide blade with lots of teeth. It is also wise to get a face shield, ear plugs and hang on tight!

[ljmathias]

Thanks, guys- I'm pretty good with wood, not so much so with metal.  Besides, I like Arky's idea of trying it in wood till I get it right, then having a CNC make the metal versions- well worth the effort seems to me.  I'll let you all know how it turns out just as soon as I get around to it- and you all may have heard what a roundtuit is, right?

Lj