iDRY Vacuum Kilns

Sponsors:

Dovetail Log Cabin

Started by fred in montana, February 07, 2015, 08:22:35 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Jeff

Fred, how uniform do the logs have to be for your jig to work and will it work on two sided logs with the curves on the outside and inside? 
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

fred in montana

If you are planning to have zero gap then the log dimensions have to be very consistent. I prefer a chink joint myself. If the logs are to be chinked then the log dimensions can vary a lot. You could also go with two sided logs (flat on the inside and outside).

If you want the flat sides to be on the top and the bottom and want to use my jig system, you have two options:

1. Cut a third side to make a D log. The jigs need to attach to a flat face. They attach to the side of the log that is the interior face.
2. Instead ofcutting the interior face full length, you could flatten an area about 2 feet long at each of the log. This will be enough space to attach the jig. The two flat areas would need to be in the same plane.This would be a pain to do I think.
woodmizer lt15, mf 65 tractor
logdovetailjig.com

Jeff

If I cut my logs on three sides, I'm afraid they will fall under the required dimensions to meet code. My logs are mostly 9" or slightly bigger in diameter
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

jwilly3879

Jeff, where is the inspector getting the the required dimensions from? Or is it an energy code thing? Lincoln Logs uses a butt and pass system and they are solid all over. There is also another home company that uses 4x8" timbers for their packages with 4" thick walls.

D L Bahler

You can make a gapless/chinkless cabin without having consistent dimensions in the logs. People do it all the time.

'Verzinkter Block' or dovetailed log cabins built in eastern Switzerland and Austria do this all the time with no problem -these being the ancestor of our American dovetailed log cabins which are something of a simplified Austrian style.

The thing is when doing this, you have to figure the sizing and location of the top and bottom of the joint on each log separately.

What I do -I use interlocking corners, but the same idea will work with dovetails- is this:

Starting with a staggered joint, you measure from the point where the top log will come on the bottom log (which is perpendicular) Then you measure the distance from the bottom point up to the top of the bottom log. The center of the slope of your dovetail must come to exactly half of this measurement, then you cut a corresponding joint on the bottom of the adjoining log.

When you do this, you will create a joint that fits tight, and allows your logs to fit tight along their entire length.

This though requires that the top and bottom faces of our logs be milled and planed very flat.

If you don't have very accurate faces, you must instead lay out each wall on the ground with the logs butted against each other as they would be in the wall once assembled. This way, any inconsistencies and deviations from perfection are accounted for.
So now, instead of measuring to the top and bottom of our logs we have to go by reference lines that are chalked down the middle. We go up the walls, transferring information from adjoining walls so that each joint is unique and accurate.

This is how the Swiss have done it for several thousand years. It is, more or less, a method of log scribing. It's done this way even if the logs are planed to super accurate dimensions, as they tend to do, because you should never trust wood to be perfect. 

Jeff

I don't want to spend an entire summer trying to learn how to cut joints and probably ruin several logs in the process. I need the kiss method.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

D L Bahler

In that case, the American appalachian style is the right thing. This is exactly why it exists, being an adaptation of the more complicated European methods to a situation where it was more important to get a house up fast than it was to build a super nice building. Pretty much, they just eliminated the most complicated parts of the process.
It's the rough, rugged pioneer house, and as  such the style has a certain rustic charm.

D L Bahler

I recommend the Appalachian method to people who want a good DIY project without having to master a difficult concept, and who don't have the luxury of a lot of time to do it. The trade off is, it will keep you busy down the road with maintenance, adjustment, etc. 

I recommend the European methods for people who can put more time and effort into it (or pay me to do it,  8)) and who want a building that once it's up, you don't have to worry about it any more. The trade off here is, if you are doing it yourself then it is a lot more complicated and you are more likely to make a mistake learning it.

Roger Nair

In my area, the Appalachian (with earthen chink) style log house that have survived the best with simple maintenance are the ones that have been sided or brick veneered.
An optimist believes this is the best of all possible worlds, the pessimist fears that the optimist is correct.--James Branch Cabell

landscraper

Jeff could you use a log corner connection like this? 



I drew it with square logs but I think it could be "2 sided" logs (top&bottom milled, sides still round) too.  I got this idea from another post somewhere, the guy mentioned putting a few squared up logs at a time on the deck of his mill and cutting in at 3" so that there would be good consistency in notch height.  It uses a cheater log on the bottom and top courses to finish out the odd 3" interval.  It could be scaled to whatever size logs you are working with.  When I drew it I had 6" square logs in mind for a little hunting cabin in the woods, not a full time residence.  Probably still some chinking involved.

I can't speak to the merits of this type of notch vs another as I've built exactly zero log cabins.  It just looks like a simple system of joining logs at corners. 
Firewood is energy independence on a personal scale.

Jeff

I'm thinking with smallish logs that might not be the strongest for me. Looks to me like lots of places for moisture to lurk though.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

landscraper

Yeah that's a concern for sure - I think only the dovetailed or coped joints really "shed" water, even butt & pass has a vertical seam that coincides with an inside corner every other course that I wondered if it would be an infiltration point.   Back to sketchup.
Firewood is energy independence on a personal scale.

D L Bahler

Have you considered a passed lap joint, like:


 

It's really quite simple and very fast to do, far less complicated to lay out than a dovetail joint
It also locks the timbers against twisting and creates a tight joint.

Roger,
in Indiana all the log cabins were immediately clad with siding. The pioneers would bring a barrel of nails and a wagon of wood siding with them into the forest, lay up a cabin and put siding on it.
Quite a few of these are still standing today, often surrounded by an expanded structure as the original house was built onto over the years.

They used a modified v-notch that I'm rather fond of, which made a good secure and tight joint.

fred in montana

The (half) dovetail jig method is KISS.

Snap a chalkline down the center of the log. Attach jigs to each end, at the correct distance apart.

Saw all of the notches in less than 5 minutes.

Each log in a wall is interchangeable.

When the logs are stacked, the distance from chalkline to chalkline is always a constant. Each chalkline is level.

This is true even if the logs have varying heights or if they are just sawn on the inside and outside face.
woodmizer lt15, mf 65 tractor
logdovetailjig.com

Jeff

But I need to saw on the top and bottom face to keep my wall thickness up.  If I put my sawn sides in and out, because of my available log size, they become to narrow to meet the code. Doesn't that leave me out?
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

fred in montana

Can you ask them for a variance? It is not a safety issue after all.

woodmizer lt15, mf 65 tractor
logdovetailjig.com

Remle

I think this is what you are looking for;

Quote from: Jeff on February 14, 2015, 09:39:01 AM
Fred, how uniform do the logs have to be for your jig to work and will it work on two sided logs with the curves on the outside and inside?
Quote from: boscojmb on February 09, 2015, 09:16:38 PM
Here are pictures of a set of jigs that I made last summer to notch and point 2 sided logs. Feel free to copy them if you want.

Point jig


Notch jig


Checking the notch


Cutoff jig


UHMW spacers on chain saw bar



I hope this helps.

Jeff

What are the typical costs if a guy was to leave the gaps and chink?
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

fred in montana

I had about $450 in materials for chinking the 11x15 cabin. That was with gaps that average around 2.5 inches. If the gap was kept to 1 inch I think it would have been about $150.
woodmizer lt15, mf 65 tractor
logdovetailjig.com

Magicman

I am planning for ΒΌ" so my chinking cost should be minimal.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

mrector

Awesome  cabin Fred!  I like what your doing with your website, I will be ordering plans for a jig. I have a couple questions.  First is when you leave chink gaps, you just screw in ends on dovetail?  Or do you put in some sort of small spacer that chinking would hide so that beams possibly wouldnt sag over time?  Second is did you insulate floor or just ply, then flooring?
Mikey

Ps if I ordered plans I would never accept a refund. But id send in pics.
Woodmizer LT35HD25 brand new!
Stihl 044 and my favorite: ms260 pro
Homemade logging arch
Homemade hitch log picker-upper
DanG Deadheader log loading trailer.

fred in montana

Thanks Mrector. If the span from end to end is long enough that sag is a concern then I put spacers between the logs at midspan. The spacers are hidden behind the chinking.

In this case I just wanted to give extra support to the log supporting the rafters:



 

You could insert spacers between every course where needed.

I normally don't use screws or nails at the notches. They interlock.

I did insulate the floor from underneath.
woodmizer lt15, mf 65 tractor
logdovetailjig.com

Magicman

Quote from: fred in montana on February 18, 2015, 06:02:25 AMI normally don't use screws or nails at the notches. They interlock.
I have been wondering about that.  I understand the interlocking at the corners, but there is nothing tying the roof to the foundation.  Maybe I am just being overly concerned.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

fred in montana

 Here is one way of accommodating log settlement at doors and windows:





 

woodmizer lt15, mf 65 tractor
logdovetailjig.com

Magicman

Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Thank You Sponsors!