iDRY Vacuum Kilns

Sponsors:

Tenon shoulder surface at post top to plate joint

Started by trouts2, September 14, 2018, 12:11:21 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

trouts2

Related to this post:
Help for a beginner << on: January 12, 2016, 09:27:12 PM >>

 In the picture the top beam is a plate and the lower the top of a post.
 
 Would reduction on the tenon matter?  Would a housing on the plate matter?  The idea being more bearing surface on the tenon shoulder.  Looks is not a factor in the question. The mortise and tenon would be cut in the same locations but without reduction.   Also, how do you get to the gallery without making a post?








The joint would look like this but without the mortise housing. 


 

PC-Urban-Sawyer

Look at the left hand colum which contains sponsor links. At the bottom is the link to the Toolbox and right above it is a link to the Gallery. Once you reach the Gallery home page, at the top there's a link to "My Gallery"...


trouts2

PC-Urban-Sawyer thanks.  Never looked hard enough over there as it was all ads.

Jim_Rogers

Quote from: trouts2 on September 14, 2018, 12:11:21 PM
Would reduction on the tenon matter? 
Would a housing on the plate matter?
Maybe, maybe not.
You have to understand that the reason why the plate has a housing and the post has a reduction is to eliminate the variability of the timbers from being rough sawn. If you don't do a housing or a reduction there is the possibility that the plate will not sit level. For example if the plate is 5 7/8" tall on one end and 6 1/8" tall on the other, and you don't do a standard 1/2" under housing then the plate will not be level when you assemble it.
You could/should learn to cut the joints per the standard procedures, so that they will come out right every time.
Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

trouts2

 
  I think I understand the square rule and mostly using it as the base for layout.  But I feel due to the crummy edges on so many logs I have to mix with scribe layout using level and plumb line to find where the reference or adjacent edge might have been if they were available.  For example for an end that veers off I use a 6 foot level if the beam is reliable enough with one end next to where it veers off.  I then use the square against the level to span the gap as if the level side was a reference edge.  When one of the reference faces dips or rises causing a framing square line to be off from 90 degrees for 1/4 of an inch off on a side I use a plum line and level to layout where the line should have been if there was a reliable surface to use the square with.  Some places are out of square that could be cleared up with a housing some are larger but most often the reference face I'm measuring that from itself is off.    

 I understand the benefits of the square rule related to housings to clear up beam variations.  I intend to use the square rule for joints but it won't be straight forward by a long shot due to variations in the beams.

  Maybe I should have qualified the question more.  

  The second picture showed a tenon with no without reduction or the ½ inch rule so I thought might be ok.  Doing less layout seemed like it might be better at the post mortise and tenon to avoid introducing error.  In this case the plate end was true to what would be the tenon cheek.  The other mortise would be level lined to the first.  That may make the top of the beam off but I don't care so much as it will be off anyway.  All cutting on the top will have to be done with special treatment due to thickness variation.  I can't just measure up from the reference face as it is unreliable.  I'd have to snap a level line as a base for a row of bird mouths.

 

 

 


  Pictures of a couple of sill laps.  The one with the live edge is the worst log of the batch and I thought it ok to use in the sill.  In the other picture the dark beam 90 is on.  The white log leans to the left.  The beam was oversized so planed to match the dark log.  The hump in back of the white log lap can stay there as nothing will mate to it.  The top left side of the white log also leans to the left and will have to be planned for the sheathing lay flat.  That side is the reference edge.

trouts2

  What is the maybe part?  I guess that is when a tenon is put into a reference face?  Are there other situations excluding sills and braces?

Don P

If the member is on target dimension with square rule then no reduction is needed.
Another way is simply remember that the goal is a level plate top, you can vary post length to achieve the goal as well.

I'm guessing the top sill in your last pic is hanging out beyond dimension by the amount I see its left edge overhanging the lower sill. That looks to be about the same as the amount of slop in your right side of the joint. Scribe that and tune that joint up till you get on dimension and tighten the joint up. The lower pic shows you were cutting one side of the joint to a dimension the incoming wood could not provide, that also can be scribed to fit seamlessly or reduced to a square timber that will fit tightly. Just things to keep playing with and improving as you work with funky wood.

trouts2

>>"If the member is on target dimension with square rule then no reduction is needed."

   Sobon mentioned going into a reference face a housing would not be needed but he did not expand on that like for a good adjacent side or other places where the beam was true.   I can see where in a crew situation or a complex build by 1 or two people following some guidelines would be useful.  The situation I was thinking about was for the 4 post tops to plate joint.  Given the crummy logs I've got I thought it might be useful to limit layout and reduce all four plate bottoms to a similar dimension flat and leave it at that.  I ended up cutting the housings anyway.
  The 4 post tenons were cut and mated to plate mortises.  I fitted them on horses then measured the squareness of the posts to plate, plate to post bottom distances think they are ok.  The plate tops should be level when sitting on the sills.  

On the comment of overhang on one side and slop on the right side.  I think at the time I was happy as a  calm that the beam got cut and placed and the right side slop was something to live with.  The left overhang was to get trimmed square later.  The siding could go on as is it but would be much better with trimming.   You are right though, the correction was not difficult.  I was probably burn out at the time to do more.  Moving the beams around is not so easy.  But for me the layout is much more taxing.   I watch videos of builders doing layout on nice logs with envy.   Often I'll pencil a line square to the reference edge with the framing square and flip it over to see if the tongue will land on the same line and  half the time it doesn't.   I'll try to figure out which position is likely true.  Often I'll snap a line to help estimate where the arris is.   I'm constantly measuring and remeasuring to avoid a bogus cut.

This comment is a dilly.  "Fitting the fuller sill to the reduced size sill" would have been cake but never occurred to me.  The focus on that log was it tapered at the end in the length direction going into the lap.  That was one thing.   All the sill beam ends were different sizes so I think I cut all top lap parts to be the same thickness and varied the bottom part to make all four joined laps the same thickness.   I was preoccupied with that.  It's a shame to have that gap in there so needlessly but I missed it.

Thank you for the comments.

   Jim: 
   At least I think my issue with standard (square rule) procedure is this.   Since the arris on one end is not in the same plane as the other then cutting the mortises to the arris would give me mortises that would be off from each other.   They would not be in the same plane.   Maybe I'm missing something or not applying the square rule correctly but I think I cannot follow it if my reference face/edge is unreliable.

Thank You Sponsors!