Machine is not consistent

[jeff412]

I can't see to get repeatable results. Every time I measure a board I get a different #. I just carved the Autumn Leaf dish project and 3 1/2 hours later I find that it carved the front side off from the back side by about 1/8". I always put masking tape on the board. I do have the rubber o-ring on the brass roller. What else can I check?

Jeff

[lawrence]

is your workpiece completely square and flat? - I mean like face joint, then edge joint, then plane, then tablesaw the edge flat? This seems to make a big difference for me in how the piece turns out.

Lawrence

[gashawk]

Check your MPC, drill a hole through the pattern and make sure its strait. The pattern should be locked to the grid.

[jeff412]

is your workpiece completely square and flat? - I mean like face joint, then edge joint, then plane, then tablesaw the edge flat? This seems to make a big difference for me in how the piece turns out.

Lawrence


Yes, it is. Nothing obvious anyway.

Jeff

[jeff412]

Check your MPC, drill a hole through the pattern and make sure its strait. The pattern should be locked to the grid.

It doesn't matter which mpc I use. This one was purchased through the pattern depot.

Jeff

[lynnfrwd]

Rubber belts or sandpaper? No little divets or dents on edge? No warping of the board?


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[jeff412]

Rubber belts. Board looks good.

Jeff

[fwharris]

How is the tracking when the board moves through the machine? Does it stay square against the rail on the display side?

LG would say "don't use place on center" but to use place on end. This has the machine use only the corner of the board as a reference point vs the width and length to find the center of the board. (I think I got that right)...

[GrammaPam]

I am so glad someone else brought this up. The belts or the roller Do Not always move at the same pace. Last week I carved a board where the recessed carve was 32” long; when the outline came around with the 90 degree V bit it was one and a half inches (1 1/2") off. After reconstructing the art so the carved area was just an outline, the line carved down to the opposite end, then, without going back to the beginning, carved the inside line as it headed back to the start point and it was okay. Looks better to someone who didn’t know what it started out as, but not the effect I wanted.

There are plenty of examples and I’m sure, a lot of excuses, but it is a fact. The board does not travel consistently at the same rate. Now 1/8” over a 40” board may not be a real big problem, sometimes; but this piece is firewood. One way to prove the theory without carving is to repeatedly measure the same board without moving it. Does anyone else get different readings? Or measure a board and see if the machine registers the same number you got. One question I have: is there a way to lubricate or maintain the rollers or belt besides a good cleaning?

In my instance above, the lock was on. There seems to be less of a problem without it.

Also using rubber belt, the Carve Tight and the first machine purchased. It has fewer idiosyncrasies over all than the next two I bought, hoping to get a machine that works better. I keep the board edge sensor clean. Used on feed and off feed roller supports. Alway double check the tightness of the bits. The board was nice cedar, planed and straight.

I don’t like to seem to complain a lot, not a machine technician, not real mechanically inclined or an accomplished woodworker but I’m not completely stupid. If there is a way to make the machine work better I want to help find it.

Thank you for any input, triple thank you for a solution. And thank you Jeff for starting this conversation.
G.P.

[jeff412]

How is the tracking when the board moves through the machine? Does it stay square against the rail on the display side?

LG would say "don't use place on center" but to use place on end. This has the machine use only the corner of the board as a reference point vs the width and length to find the center of the board. (I think I got that right)...

The board tracks fine through the machine. The problem isn't just with this project. If I measure a board then re-measure the board I will get two different results. The HD belts were installed by LHR, so I have no way to know if they changed the o-ring or not. That may be my problem, not sure. I will definately try your suggestion and place the project on the end.

Thanks,
Jeff

[GrammaPam]

I checked the O-ring possibility, Jeff. Don't think that's it. Good Idea LG and FW Harris. I do try to insert the board consistantly but do use center the board.
G.P.

[b.sumner47]

Has anyone checked the head pressure ? Capt Barry

[jeff412]

Has anyone checked the head pressure ? Capt Barry

I just went and checked my head pressure and it is 81.8 lbs consistently.

Jeff

[GrammaPam]

Good idea Capt Barry. Tom, would you bring the scale you use for this purpose to the meeting Wednesday. Mine got borrowed and never returned so have been without one for a while.
Thanks,
G.P.