Dan's Rotary jig questions

[Russel]

Well Dan, I have the jig built, except for bearings, which I found listed at Grainger's, and the three springs. On the roller lifter, I see a spring under the top concave portion. The spring portion visible is only about 1/4". I suspect the spring is longer and is sunk into a hole under it. How long should this spring be and how deep should the hole be? I made assumptions about fasteners and everything seems to work on the bench. Will I need any 2d or 3d features for Designer, in order to get started? I am studying other projects by others, but I may need to be led by the hand to get a project carved.

[bergerud]

The spring is in a hole. The reason for the spring is to push back up on the roller to keep the forces almost balanced. You want the machine roller to just barely win and push the lifter down when the jig is clamped in the machine. (Listen for the click of the roller switch.) I drilled the hole deeper and deeper until the switch would just click as I clamped down the head. The balance of these forces keeps the force on the lifter bearing in the rail slot small.

You only need a pattern on a Designer board which is as wide as the dowel is long and as long as the circumference of the dowel. For example, to carve a six inch wide pattern on a 2 inch diameter dowel, I would design a 6 inch wide by 2*Pi = 6.28 pattern in Designer on an 8 inch wide board. Then carve it on an 8 inch long dowel. (There needs to be room for the rail to roll on the end.)

The basic procedure as I remember is this: With the dowel set up in the jig and the jig in the machine, first push the jig back and clamp it down. Releasing the tension on the rail with the lever, slide the rail in just past the position where it keeps the roller up. (The machine will think the board in under the roller.) Now place a short piece of black electrical tape on the front of the dowel. (The machine will think this is the end of the board when it rolls to the top. Don't laugh, this was my stroke of genius! The tape is moving the wrong way but the sensor does not know the difference!) Load the project and choose place on end (or corner). (If you choose center on board, the machine will roll the rail right out the back looking for the front of the board.) After the machine has "measured" the dowel it will ask for the bit. At this point, slide the jig forward and clamp it down. The bit should touch down on the dowel and start the carve. (If the carve is deeper than 1/2", the machine will go for the sliding plate bob. This can be a problem if the bearing holders are too thick. Keep the first tests under the 1/2" carving depth.)

I will come up with an mpc to try and give it a shot to refresh my memory.