fletty
4th November 2013, 08:59 PM
I haven't done ANY woodwork for a while and so I was looking forward to returning to the shed on Saturday. I've been planning on making a guide for my mitre saw, I had a few designs in mind AND I had bought the Kreg kit a few months ago. At the beginning of the day, my mitre saw looked like this
292181
I got to work on converting the thoughts into timber and, by lunchtime I had it largely finished. I made 2 guides, a short one (up to 900mm cutting) and yep, you guessed it, a long one (up to 2400mm). The plan was to leave the short one attached but be able to quickly remove it and fit the long one when required. The long one requires the out feed stand for support whereas the short one has a hinged flap to support it….
292182
but can drop out of the way when not in use...
292183
Well, so far so good. so I set up to cut multiple pieces 400mm long to test its repeatability ….. and cut a dozen pieces ANYWHERE BETWEEN 400 AND 408mm!
I then remembered that the tolerances and errors in the 12 individual pieces that make the removable hinge and locking mechanism are additive AND …. add up to 8mm!
Back to the drawing board, which is in fact an old tree stump in the shade, and rethought the whole issue. The new design is a single piece of hardwood carefully shaped and sized to mount to the table and fit inside each of the 2 guides which allows them to slide on and off and be fixed with a single screw through the guide into the hardwood. The additive tolerance is now NIL and the multiple cuts showed no variation
292184
I was going to have to learn to learn to live with either the short guide or the piece of hardwood sticking out BUT, I also fixed that late in the day by the simple of process of fitting the long guide...
292185
… tripping over the out feed stand and snapping the piece of hardwood….. !
back to the tree stump….
fletty
292181
I got to work on converting the thoughts into timber and, by lunchtime I had it largely finished. I made 2 guides, a short one (up to 900mm cutting) and yep, you guessed it, a long one (up to 2400mm). The plan was to leave the short one attached but be able to quickly remove it and fit the long one when required. The long one requires the out feed stand for support whereas the short one has a hinged flap to support it….
292182
but can drop out of the way when not in use...
292183
Well, so far so good. so I set up to cut multiple pieces 400mm long to test its repeatability ….. and cut a dozen pieces ANYWHERE BETWEEN 400 AND 408mm!
I then remembered that the tolerances and errors in the 12 individual pieces that make the removable hinge and locking mechanism are additive AND …. add up to 8mm!
Back to the drawing board, which is in fact an old tree stump in the shade, and rethought the whole issue. The new design is a single piece of hardwood carefully shaped and sized to mount to the table and fit inside each of the 2 guides which allows them to slide on and off and be fixed with a single screw through the guide into the hardwood. The additive tolerance is now NIL and the multiple cuts showed no variation
292184
I was going to have to learn to learn to live with either the short guide or the piece of hardwood sticking out BUT, I also fixed that late in the day by the simple of process of fitting the long guide...
292185
… tripping over the out feed stand and snapping the piece of hardwood….. !
back to the tree stump….
fletty