So, after a little break to do some other work (mostly web related) today we were back in full force. Fuller force actually, since the Texas Light Brigade has come over to give us a hand here.
We made a blank, and positioned it on the foam jig.
This blank was constructed from ordinary construction grade lumber, 2x4's and some construction glue. In all there is about $25 worth of lumber in there and if we improve a bit on the stacking of the laminates I think we could get that down to about $12 or so.
Before the first side was cut the blank weighed in at 20 kilograms (roughly 40 pounds). After cutting the first side there was only 14 Kilograms left, so that's a lot of sawdust.
Cutting took a long time, easily 6 hours or so, but we spent a lot of time fixing snags and bugs. One major one was that a bolt broke off and caused the router to tilt sideways 45 degrees. It took me 20 seconds or so to get from upstairs where we hide from the noise to the cutter, by then the damage was done and we had a nice 5" long gash running straight through the blank.
We fixed the bolt quickly enough, but we feared the blank was lost.
After some measuring we decided that we could probably save the blank by filling the gash with some bondo or so.
The toolholder was giving us more trouble, this time the router moved as a whole within the ring that held it. We cut the ring in half and added some straps to secure the router against the remainder of the ring. No more play from that front.
The bearing in the router is starting to sound rough already, not too good for a brandnew router !
Surprise, after all the passes were done, the gash wash nicely removed and turned into sawdust too, so no need for ugly fixes. Since this blade will be wrapped with fibreglass when we're done there would be no harm in that, but still I'm pretty happy with the way it came out.
Tomorrow we will do the second side, we have added a little more support to the leading edge to rest on because the airfoil shape came out quite close to the edge of the blank leaving insufficient support for tomorrows work.
Ron brought this carbide based insert cutter that you can 'flip' around, just like the ones we use on the lathe here. Those bits are very cheap to run (they have 4 cutting edges) and are probably a good investment for anybody using a router more than just a little bit.
After roughing out with that bit we did the final two passes with a 1/2" ball bit.
This is already getting dull, and I'll probably optimize the toolpath to be able to do the whole blade with the square cutter.
It would save money as well as time, cheaper to run and no need to change tools when switching from roughout to final cut.
pictures follow:
The blank:
Beginning of the 1st pass:
The shield that protects the rack from fouling up:
Closeup of the gash left behind by the router as it swung sideways:
The new toolmount:
Final pass on this side, look at how smooth it comes out:
Done !
Anybody interested in some cheap fuel for a woodstove ?
