| The most important criteria for this jig was speed - if it took too long
to lock a log in place, I wouldn't be bothered using it and would take
risks. While I achieved a reasonably quick action clamp, had the UniStrut
been of better quality, it might only take 1/2 to one turn of the handle
instead of 1-1/2 to 2 full turns to lock onto a log. The very poor quality
of the UniStrut actually made the whole thing difficult to produce - the
inner lip that the dogs lock onto varying up to 3mm over the 1100mm length
and galvanising lumps up to 2mm thick in places.
The holes drilled along the back of the Unistrut serve to allow sawdust
to drop through and to reduce overall weight.
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| I didn't actually have to buy anything to
put this together as I had all the necessary bits hoarded already, including
the remains of an old 'F' clamp I used for the screw.
I've glued 120 grit emery paper on to the faces of the jaws for good
grip as well as tapping several holes to take spikes for logs that don't
present a big enough surface area for the grit to hold. Though I'm not sure
I'll ever need it, the design allows the clamp to hold from 1000mm in length
right down to zero.
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| The clamping action is similar to many
commercial 'F' clamps. The first half turn or so tilts the 'dogs' backwards
until they bind on the rolled lip of the UniStrut so that any further
turning of the handle pushes the jaws into the log.
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| The clamps are 150mm high which is enough
for most saws but mine has a cutting height of 460mm (minus 23mm for the
sled) so I made some extra grippy extensions for the rare occasions I want to hold round material that
big. (I knew that old Jacksaw my son 'used' would come in handy one day!)
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Using the sled... |
| I have even had small logs like this piece
of Yellowberry Bush catch and roll into the blade when crosscutting - very
upsetting experience! I spend a lot of time cutting small egg blanks to turn
and trade and the sled allows me to hold them securely with fingers nowhere
near the nasty bits!
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| Getting a slightly bigger log ready to
resaw is easy as with the sled.
At left, docking the ends if need be.
At right, taking the first slice off one side.
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| Adjusting the saw to minimize drift will be
important while the sled is using the mitre slot to guide it, but once I
start cutting green timber, I may have to remove the guide bar and steer it
by eye as the sap and crud build up on the blade tends to cause lots of
drift problems.
At left, taking the second slice off with the first flat down on the
sled.
At right, the resulting billet ready for slicing using the normal
rip-fence.
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| ...and finally a way to hold those mongrel root-balls safely!!!
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