So, I’ve been designing a timber frame sawhorse system to be used in the field at the jobsites, and in the workshop. I call it a “Mare and Colt”.

The Mare and Colt system has four parts:

~A timber trestle sawhorse (Mare).
~An additional timber and hoof (Colt) that is joined to the Mare.
~A re-moveable and portable tool shelf that slides into a pair of dados under the deck of the Mare.
~A series of holes drilled through the top of the deck on the Mare, used in combination with friction/ wedge type hold-down clamps.


http://www.forestryforum.com/gallery/displayimage.php?album=2237&pos=0

http://www.forestryforum.com/gallery/displayimage.php?album=2237&pos=1


The Mare stands 6 hands at the withers, (24 in. to the top of the deck) All of the pieces are made out of 6x8 pine. (I do have a team of Mares w/ Colts that are made out of reclaimed treated pine guard-rail posts, for use outside in the elements at the jobsite.)

I like to use 6x8s because:
~Of the added joinery needed to attach the colt and the dado for the tool tray.
~I can safely rest my boring machine on the deck (8 in. wide).
~A large framing square can hang off the edge without tipping.
~The large tenons and shoulders of the legs give more rigidity without having to use diagonal bracing.
~And I like Mares with big butts!

I chose the height of the Mare to be 24 in. because I work on a lot of 8x8s. So, an 8x8 on top of a 24 in. Mare gives me a working (layout/ saw) height of 32 in. I’m about 5’10 with my steel-toed loggers, and this seems to be a good height for me. Now take someone like Jim_Rogers who is 6’1”, or someone who is even taller, and this might not work for them. I came up with an equation that might help determine the correct height for someone of a different height.

Take a tape measure and hold it along your side with the tip/end on the ground, stand perfectly straight and see where your figure tips touch the tape. For me it is at 27in. I subtract 3 in. and that is the top of my Mare. So feel free to add or subtract from the length of the legs to match your work height.

The Colt is also built out of 6x8s and only has one hoof. Since there is no leg, that means that the deck is joined directly to the hoof, using a 4x4 that is mortised into the underside of the deck and the topside of the hoof. The other end of the deck has a tenon that then mates up with a mortise on the lower section of the Mare’s leg. The mortise has a full housing of 1 in. so that the Mare’s back hoof will carry half of the load of the Colt’s deck. This joint is not pegged so that the Mare and Colt can be easily separated, in case they need to be moved to a different pasture, or if you need to clean their stall. (Pine shavings.) The Colt stands 3 hands at the withers (12 in. to the top of the deck.) This step down from the Mare’s deck, is used for storing beams to be worked on and also is a nice height to rest an 8x8 during the boring process, especially if you are using a boring machine. The seat height for an 8x8 plus machine is between 20 & 22 in. Most people will be able to rest their feet flat on the ground without the feeling that they are riding bareback on a real horse.

The tool tray is sized to allow a framing square to lay flat within the sides of the tray, as well as any number of chisels, layout tools, mallets, etc. The dados are cut ¼ in. deeper and ¼ in. taller than the outside tray frame so that it can slide in and out. This way you can take the whole tray, with the tools that you need at any given time, and move them to any other Mare. Or, if you are like me, and you want to take your tools inside without picking them up individually, just take the whole tray out. The tray is also designed to slide under the Mare from one side to the other. I also incorporated a couple of blocks to the underside of the tray so that it can straddle a beam at any point, and with the aide of a wedge, the tray can be temporarily secured to a beam that sits parallel to the one you need to work on. This way, the tools are never in your way, or sitting on the ground, or in a pail, or falling off the beam as you are using your chisels.

The final part of my system is the hold down clamps. I will be posting photos of the clamps in action. I have a friend who is a blacksmith, and I asked him to make me a couple of hold down clamps which are similar to these.
http://www.amazon.com/REACH-BENCH-HOLD-DOWN-CLAMP-JORGENSEN/dp/B000KUZM0S

I did opt to have him use ¾ in. rod instead of 5/8 in… it just seemed to hold better. These clamps are inserted into any of the pre-drilled holes that pass through the top of the Mare’s deck. The hold down clamp secures smaller pieces of material like a 4x4 diagonal to the top of the deck with a simple tap of a mallet, driving the clamp into the hole further and wedging the rod against the inside surface of the hole. A simple tap on the back side releases the clamp, and the work piece can be repositioned or removed completely. This system is like having a couple more hands to hold the work instead of trying to saw with one hand and hold the work-piece steady with the other. No more getting your leg up on top of a short piece of 4x4 so that you can pin it down with your knee while cutting the end with a circular saw. Whew!

Well hopefully it’s clear as mud.

(I am not sure how to post a Sketchup model.)


Let me know what you think.

Rooster