Knife Plate Slotter for Timber Framing

[sbebuilders]

California Knife Plate Slotter - Mortiser for 6x6 post.

Okie Knife Plate Slotter - Mortiser for the 5 1/2" x 9" GluLam Beams.
(AKA Chainsaw on a Stick)

http://sbebuilders.blogspot.com/2014...r-framing.html

Sim
cal-slotter.jpgokie-slotter.jpg

[larryh]

Re: Knife Plate Slotter for Timber Framing

I had a job in 02 that had enough knife plates that I designed something like that and had it fabricated out of stainless steel. just bolts onto the saw bar with the bar bolts. The top side of mine is open so i can slot into the ends of 6X12 (or 6x anything) beams for T brackets.
I've used that jig many many times.
Also got that same drill jig back then too. Love it.

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

Larry, can you post a picture of your stainless steel knife plate slotter? I still have the main house to frame. It will probably have some "T" knife plates to install.

Sim

[m beezo]

Re: Knife Plate Slotter for Timber Framing

Sim,
that second picture looks kind of dangerous to me. Maybe I am not looking at it right but if that thing kicked back can the guy holding onto the jig get out of the way?

[larryh]

Re: Knife Plate Slotter for Timber Framing

Larry, can you post a picture of your stainless steel knife plate slotter? I still have the main house to frame. It will probably have some "T" knife plates to install.

Sim

I don't actually have any pics of it but I'll get some for you. It's a very simple contraption.

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

"looks kind of dangerous"
That's why I called it the Okie Slotter. Something my father and his brothers would have come up with.

We had zero kick back from the chainsaw, only because we slotted the beam with the router first. However, yes it was dangerous, but I still have two legs. We ended up clamping a 2x4 to the beam on each side of the jig for the length of the slot, but didn't take any pictures of the process. The 2x4's clamped to the beam make it feel a lot safer.

[larryh]

Re: Knife Plate Slotter for Timber Framing

P4100023.jpgDSCN0506.JPGDSCN0507.jpg

Here are pics of the saw attachment we made. Sorry no action shots, must have had a saw in my hands at the time :)

It's made so that the bar is centered 2-3/4" in and 2-3/4" up from the bottom. I just have the engineers draw the brackets for those dims..

To use it we stack the beam or post we want to slot, on top of another 6x and put a small spacer between them (usually just use a couple knife plates as that's what's always within reach). The lower 6x just supports the saw. The shims allow the tool to slide. Just gas it and push it in.

95% of the beams we used had butt joints at the posts so this works great for those end plunges. When we have a long t-bracket in the middle of a beam I do it by hand. Lay it out, drill a series of holes to shape/start the slot, then remove the rest freehand with a 12" chainsaw. Finally all the visible slots get cleaned with a router and plugged with a spline after install.

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

Great jig Larry. I can see the post beam connection with the "T" slot, but what's the connection on the rafter to the beam?

Sim

[larryh]

Re: Knife Plate Slotter for Timber Framing

Those rafters were only 4' so the engineer only called for structural screws. We mortised the beams just 1/2" to hide future shrinkage gaps.

Connections on the longer rafters were simpson cjt (also in a mortise). You probably are familiar, but if you haven't had the pleasure.. those brackets are awesome. Yes it takes some skill and time, but they make super tight, strong, and CLEAN connections. We recently used them on 21' rafters. Pretty easy to use one-off, but if you have a lot of connections to do, a template and nice drill jig really make it easy. No, i'm not a simpson rep :)

[Dick Seibert]

Re: Knife Plate Slotter for Timber Framing

Sim:

Remember my Saratoga house? I got all the columns standing and beams in place, started looking at the knife plates and decided that there was no way I could butt the ends of the gluelam hips and valleys into the columns and slot them, I shut the job down and had the building re-engineered to a full steel frame eliminating the gluelams altogether. knife.jpg I had Keith burn off all knife plates. In the picture it wasn't the horizontal knife plates that bothered me, look at the top column with both the two horizontal plates and the large diagonal plate for the hip. The only way I could figure how to slot it was freehand with a chainsaw.

[larryh]

Re: Knife Plate Slotter for Timber Framing

Sim:

Remember my Saratoga house? I got all the columns standing and beams in place.... I shut the job down and had the building re-engineered to a full steel frame eliminating the gluelams altogether. [ATTACH=CONFIG]30452[/ATTACH].... The only way I could figure how to slot it was freehand with a chainsaw.

holy crap that sounds like a lot of expense to avoid using a chainsaw! :)

The hip bracket in my post above went 20+" or so in every direction and yeah, I was scratching my head a bit. The hip had to be slot from the bottom just for installation. I was able to plunge that one and then open up the bottom with a router, but there's nothing wrong with a freehand chainsaw cut as long as your comfortable using chainsaws. Just clean up the slot with a 1/2" router cut to accept a nice spline filler.
Here's a freehand chainsaw slot (cleaned up)and i think you can see in the previous pics some filled and finished. They looked quite good then, and still do. huff 002.jpg

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

Dick,

Yes, I do remember that knife plate connection. At the time I thought it a hard connection to make with the beams and knife plates. I think it was suppose to have 3 knife plates. One for each of the hip rafters and one for the king common rafter. I think the slot was suppose to be about 16" in length.

I had a similar slot to make on this project. The 45 degree beam had a knife plate at each end of the beam. I cut the beam about a 1/4" long on each end of the beam and make a cut square on each end of the beam. After I slotted the beam with the Okie knife plate slotter I cut the beam to length with a 45° cut on the ends of the beam. The Same method could be used for slotting hip rafters.

Sim

beam-2.jpgbeam-1.jpgbeam-3.jpgbeam-4.jpg

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

Larry,

"The hip had to be slotted from the bottom just for installation."

Yes, that is definitely the main issue using knife plates with hip rafter. Did the head cut of the hip rafter get the knife plate as well?


"Just clean up the slot with a 1/2" router cut to accept a nice spline filler."

Good trick Larry, with cleaning up the slot with a router for the spline.


Sim

[larryh]

Re: Knife Plate Slotter for Timber Framing

Hey Sim,
Thanks!
This hip had no special hardware at the top. We actually had to slot almost all of the beams through the bottom, because there would be no way to assemble the structure otherwise. There were at least 50 plates on the main house, then ~10 on the garage, and the master suite had another ~10. This shows the new master suite, and about half of the porch on the 12 year old main house. Fun stuff!


DSCN0344.jpg


Then there's this crazy section with Knife Plates on Crack

DSCN0062.jpgDSCN0329.jpgDSCN0325.jpg

[sbebuilders]

Re: Knife Plate Slotter for Timber Framing

Larry,

With an earthquake with a magnitude of 6.0 that occurred near American Canyon, CA this morning 3:30 am, it would be interesting to see if the knife plates held up on this house.

Sim