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General Forestry => Sawmills and Milling => Topic started by: quadracutter222 on November 01, 2019, 01:38:36 AM

Title: Split a beam on diagonal!??
Post by: quadracutter222 on November 01, 2019, 01:38:36 AM
Hello and happy Halloween!

Had a customer ask if I could saw 8x8s on the diagonal to produce two right angle three sided beams. Naturally being a new naive sawer said yes.

Any one done this before?  Thinking of some sort of jig that fits the bunks.

Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 01, 2019, 01:47:27 AM
Happy Halloween back at ya.  I have never done a triangle profile, and to be sure I understand, is it an 8 x 8 x 8.  with 3  60 outside angle.
or are we splitting an 8 x 8 beam in half on the diagonal which would be easier. so a 90 and two 45s? i.e. 8 x 8 x 11.3.
if you do this will you have to change you handle to tri cutter?  :) :) :) @quadracutter222 (http://forestryforum.com/board/index.php?action=profile;u=41095)
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 01, 2019, 02:06:51 AM
If you are sawing 8 x8 square beams on the diagonal, you just need a jig made from two 2 x 8s at a 90 degree angle to hold the beam.  maybe then a notch at 90 in a brace/leg to hold it so it looks like a "V".  adjust your height, and saw away.  this is what I thought you were asking based on your question.  how long will they be.  if very long, and if twisted, may not come out perfect along the edge.  would to be good to know what the customer plans to do with them, and be sure to limit expectations.  what kind of wood?
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 01, 2019, 02:19:38 AM
so a or b?



(http://forestryforum.com/gallery/albums/userpics/51041/5F61E3EE-2CC0-43C0-B928-34415960B225.jpeg?easyrotate_cache=1572589103)
 

also how many?  the more you will do, the more effort I would put into the jig.  
Title: Re: Split a beam on diagonal!??
Post by: Nebraska on November 01, 2019, 07:17:08 AM
That would make a different look  for a celing.  I can't recall ever seeing one if that is where it ends up.
Title: Re: Split a beam on diagonal!??
Post by: Don P on November 01, 2019, 07:50:37 AM
That would not be much of a beam structurally and would more than likely produce two bananas. Make sure you are not on the hook for the results.
Title: Re: Split a beam on diagonal!??
Post by: moodnacreek on November 01, 2019, 08:24:48 AM
If it can be done it is done. A mill near me used to cut triangles for a customer to buck into wedges. Apple bin [boxes] have corner boards in the bottom cut made from diagonally split 3x3. Some people call this product skewback. Somebody put a traveling bandsaw over a log lathe and ran both at once to make spiral posts.    And then there where stone boats made with no iron front, the planks being sawn curved up in the front.
Title: Re: Split a beam on diagonal!??
Post by: Magicman on November 01, 2019, 08:29:47 AM
would more than likely produce two bananas
Yup, sorta like when I was asked to saw a 12X12 Poplar into four 6X6's.  I said no, he said yes, I said you ain't gonna like it, he said do it, I did, and he didn't like it.
Title: Re: Split a beam on diagonal!??
Post by: Weekend_Sawyer on November 01, 2019, 08:33:31 AM
Huh, I was sure I replied to this post just now.

and here's what I said.

Doc, reading his post I believe your drawing A is what he's going after.

I agree with DonP it will likely bow.

If this is a paying job I would explain the risk and charge by the hour.
I would make a jig by cutting some 1' 2x4's on a 45 and attaching them on edge to another 2' long 2x4. You can toenail the 8x8 to the jig but it would probably hold itself down.

Good luck and please update this thread with your results
Title: Re: Split a beam on diagonal!??
Post by: Percy on November 01, 2019, 09:35:36 AM
would more than likely produce two bananas
Yup, sorta like when I was asked to saw a 12X12 Poplar into four 6X6's.  I said no, he said yes, I said you ain't gonna like it, he said do it, I did, and he didn't like it.
Hahahaha...I love your way of putting things....... ;D
Title: Re: Split a beam on diagonal!??
Post by: WV Sawmiller on November 01, 2019, 09:40:45 AM
   I agree with Doc's a. drawing. That's how I'd do it. It doesn't look like it should be that hard to do. Sort of like RRQS. I also agree with the MM you should warn the customer first but then i would do it if he still wanted.
Title: Re: Split a beam on diagonal!??
Post by: dutchman on November 01, 2019, 09:41:50 AM
Ive split hundreds of beam on the diagonal for local pallet shop.
Made several different jigs.
Used a wide full size 2x as a clamping board.
Cut the triangle pieces on table saw.
Mount the triangle on clamping board, screwed from underneath.
Mounted metal truss joint pieces on the triangle to hold against
The blade pressure.
The cant will move but I never had one come off.
Must set the cant on the metal holders, dropping will cause the fingers
To collapse.
Longest I cut was 8.
They were used to hold steel coils, didnt need to be pretty.
Title: Re: Split a beam on diagonal!??
Post by: Woodpecker52 on November 01, 2019, 09:51:48 AM
Would not want to bump my head on that beam :D
Title: Re: Split a beam on diagonal!??
Post by: quadracutter222 on November 01, 2019, 10:02:04 AM
Thanks for the responses!  

I am looking to do sketch 'A' in doc's drawing.  The customer is planning on using them for top plates on top of ICF forms for a 12/12 roof made of engineered I-beams (cannot let in birds mouth)

He wants a total of 40', but I am thinking of doing it in 8's would yield the best results.  

Perhaps two/three braces that slip over the bunks?  Or the X supports screwed to a wide slab or plywood then clamped?  Hmmm, anyone have any pictures?
Title: Re: Split a beam on diagonal!??
Post by: blderman on November 01, 2019, 10:15:22 AM

I had to do the same thing on a house I built last year.  I wish I would have had my sawmill at the time as I had to cut all the bevel plate using a 16" beam saw and then finish what it couldn't reach with a sawzall.  It was painstakingly slow and difficult to get an accurate cut.


Title: Re: Split a beam on diagonal!??
Post by: Jim_Rogers on November 01, 2019, 10:18:14 AM
When I did it I just put the wedge on the mill bed:


(http://forestryforum.com/gallery/albums/userpics/10095/DSCF0030-s.JPG?easyrotate_cache=1196530489)


Jim Rogers
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 01, 2019, 10:20:31 AM
I do not have pics as I have not done this identical thing, but a made a flag pole out of cedar making a tapering octagon.  would need pics and or detail of your mill, to help with finite details, but for as little as you are making, make the jig to hold the 8 x 8, and then add support over the bunks.  If you are not going to do this 5 days a week then just screw stuff together and give it a try.  the application does not sound like it requires perfection unless it will be seen and the look is a big deal.  If this is timber frame then I have seen others cut the whole top plates to this shape, and not just a cap.  so this is a filler cap.  Is the top plate really 8 inches wide?  what wood species?  you will spend as much time fitting the jig, as sawing.  sounds like fun and a challenge.  please follow up with pictures and lessons learned.  for length I think you could go longer and or plan the joints to stagger and miss the rafters.  good luck!
Title: Re: Split a beam on diagonal!??
Post by: GAB on November 01, 2019, 11:37:19 AM
Get two pieces of 2"x6"x 10" long, clamp them together and cut as deep V as possible in them.
Then put one on each end bed rail, place 8x8 in them, then clamp and saw.
That is how I saw the 5th and 6th sides of an octagonal post.
Jim Rogers is close to what I do.
Gerald
Title: Re: Split a beam on diagonal!??
Post by: Don P on November 01, 2019, 09:15:07 PM
Rather than a beam, that is called a cant strip.

The customer can be right if you want the work but I'd rip a 45 on each edge of a 2x8, measure top width, then a 45 on each edge of a 2x6 to the previous top width, stack em on the wall and bolt down. That should yield more than the required bearing area.

Even with solid sawn you really don't want a birdsmouth up top to avoid splitting the rafter.
Title: Re: Split a beam on diagonal!??
Post by: Larry on November 01, 2019, 09:50:56 PM
I sawed a few hundred for a guy.  He was chopping them into 10" long blocks, sticking in an eye bolt, and selling them as chock blocks.  I sawed doc's A pattern.  If you don't know what a chock block check this out. 

Rubber Wheel Chock with Eyebolt (https://www.harborfreight.com/rubber-wheel-chock-with-eyebolt-69828.html)

I just made a plywood form to hold the cant and split the thing.  No pictures but sawing octagon posts is similar.

(http://forestryforum.com/gallery/albums/userpics/10125/191/2011_05100004.JPG?easyrotate_cache=1305071980)

(http://forestryforum.com/gallery/albums/userpics/10125/191/2011_05100005.JPG?easyrotate_cache=1305071981)

Sawing this kind of stuff is pretty routine.  Sawing tapered sections is what separates the men from the boys. ;D >:( ;D
Title: Re: Split a beam on diagonal!??
Post by: quadracutter222 on November 02, 2019, 11:39:49 PM
What Im stuck on figuring out is do I clamp the beam or the x braces holding the beam???!  Ill be at the mill tomorrow, so well see what u come up with.
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 03, 2019, 07:19:06 AM
the prev. jig allows the clamp force to hold the cant from the side.  he is making an octagon.  I think the weight of your cant will be enough to hold it in the top of the V, but if this is for framing(and a couple screw holes do not matter), you could put some screws through your 2x jig and into the cant you are cutting. (below the blade plane).  since you are cutting in half, and not just trimming off an edge.  your clamp on the mill will hold the jig in place.  what I envision for your application is a similar jig but the back of his jig that is against the log stops would rotate 90 down to rest on the bunks or bed of the mill.
Title: Re: Split a beam on diagonal!??
Post by: quadracutter222 on November 03, 2019, 10:01:44 AM
That is what I am thinking, it will need to be screwed down to the V supports rather than clamped as the clamp would be on the underside of the V and tend to push up I would think.

Here is a picture that shows my set up.  I am thinking a wide 2x board that would span 2-3 bunks, that would get held down by the clamp.  The V supports would get screwed to that, then the 8x8 toe nailed to the V's.

Or just make 2-3 V supports that slip over the bunk rails and forgo the clamp...

(http://forestryforum.com/gallery/albums/userpics/51095/bunks.jpg?easyrotate_cache=1572793116)

I will keep you posted!
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 03, 2019, 12:10:19 PM
what kind of wood and how long at a time did you decide on?
Title: Re: Split a beam on diagonal!??
Post by: quadracutter222 on November 03, 2019, 02:15:34 PM
 Will be doug fir 8x8's and only one 8 footer and a 16'
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 03, 2019, 02:42:21 PM
I would put a 2 x on the deck building the jig up from there.  I would make the back that goes against the log stops at 90 to the bottom so it is held at that angle.  If you may use this jig in the future and or you are buying dedicated (expensive) lumber to build it, I would put some time into it, and consider using a glue and screw.  titebond 3 as example or tube construction adhesive like f26.  I might add a hand drawing of this if it would help.
Title: Re: Split a beam on diagonal!??
Post by: doc henderson on November 03, 2019, 04:48:39 PM
so I mocked this up in the shop with an old chunk of 2 x 12.  this is an end view and assumed you are using nominal dimension i.e. 7.25 inch is a 8 x 8.

 
(http://forestryforum.com/gallery/albums/userpics/51041/E20E75D9-7978-4737-B2A3-6E17C35B4184.jpeg?easyrotate_cache=1572817713)
 
Title: Re: Split a beam on diagonal!??
Post by: Larry on November 03, 2019, 10:03:01 PM
On the log stop side put maybe 4 deck screws through the "V" form but only let the points come through 1/8 to 1/4".  On the clamp side use 2 or 3 deck screws and go into the cant about a 1/2".

When I was sawing the triangles I felt like I could probably get away without using any screws and just let the weight of the cant hold it in the "V" form.  I was too chicken to try it and find out if it would work without screws.  If I did it often I would come up with something faster/better.