The Universal Carrier Base

[sunmiztres]

You are giving the extra 7" all on same board?

Using the UCB I do not need to give the extra 7"

[bergerud]

Sounds good. Put some screws in the side holes. Look also at the rails. Maybe they are curved.

In my tests on my machine, the carrier did not move more than a thousandth of an inch under the bit when the rollers rolled off. I assumed that it was not going to be a problem. Different machines are different. We may learn something here.

[sunmiztres]

Sounds good. Put some screws in the side holes. Look also at the rails. Maybe they are curved.

In my tests on my machine, the carrier did not move more than a thousandth of an inch under the bit when the rollers rolled off. I assumed that it was not going to be a problem. Different machines are different. We may learn something here.

I put 3 screws in each side as the board is 13" long. After putting the screws in I used my 1/8 shim to make sure the board was exactly sitting up by 1/8". The carve is 79% through so I looked at the edge coming out of the machine and there is a line going through the entire carve at exactly 2 3/4" on that side. The side the line is going through are the sides not laying on the rails ( the width of the board) which has me stumped. I figure if the rails were off the line would be thinner and thicker Since one side would be out of whack with the other side but to me it looks like the line is the same throughout the carve as far as depth. I will take pictures as I remove the carrier from the machine so you can understand what I am saying better and post them as soon as the carving is through.I am thinking the other side will also have the line going through but can't see that side at the moment.

[SteveNelson46]

Steve I always make sure the rails are cleaned on the carrier. Is that what you mean, the rails the board lays on?

I was referring to the rails on the Z truck and the Y rails on the machine. If there is a wood chip or debris stuck to one of the Y rails it could cause the problem. I would check the bearings also.

[bergerud]

It sounds to me like the carrier is moving in the machine when the rollers roll off of the board. Check your head pressure. Check if the bottom of your carrier is flat.

Why it is happening, I do not know, but, if you lay 1/8" shims on top of the carrier sides (after the measurement), it would have to stop.

(In my original design, I had the board up 1/4" above the sides and I used shims to keep the rollers up.)

[sunmiztres]

I will put the shim on top and see if that helps. I have included some pictures that I just carved. Let me know if you see anything that might be wrong. I can also send the MPC if you need it. Why I am thinking it is not the carrier is only because on both carves the line is in the exact same place. If the carrier was moving wouldn't the line be in different places are wiggly, not a completely straight line?

[sunmiztres]

I was referring to the rails on the Z truck and the Y rails on the machine. If there is a wood chip or debris stuck to one of the Y rails it could cause the problem. I would check the bearings also.

I did do a thorough cleaning of the machine before I started carving today so the rails on the machine are good. The bearings have no wiggle to them.

[bergerud]

That 2.75 inches is exactly when the board comes out from under the roller. The carrier is lifting up a little when the roller pressure on the board decreases. To tell the truth, I was expecting the carrier to do that but then, on my machines, it did not. It may be differences between machines or carriers. I think you will have to use the shims.

Make four 4" long shims 1/8" thick and as wide as the tops of the sides (1/2" or 5/8"). After the board is measured, as part of the clamp down step, lay the shims on the tops of the sides so that the rollers will roll onto the shims as they roll off of the board.

I think I will have to change the operation instructions as this may happen to others. Thanks for trouble shooting this problem.

[SteveNelson46]

That 2.75 inches is exactly when the board comes out from under the roller. The carrier is lifting up a little when the roller pressure on the board decreases. To tell the truth, I was expecting the carrier to do that but then, on my machines, it did not. It may be differences between machines or carriers. I think you will have to use the shims.

Make four 4" long shims 1/8" thick and as wide as the tops of the sides (1/2" or 5/8"). After the board is measured, as part of the clamp down step, lay the shims on the tops of the sides so that the rollers will roll onto the shims as they roll off of the board.

I think I will have to change the operation instructions as this may happen to others. Thanks for trouble shooting this problem.

Dan,
If the board is lifting slightly as the rollers leave the board, wouldn't that leave a horizontal line or depression?

EDIT: Maybe adjusting the infeed and outfeed tables would help.

[bergerud]

Dan,
If the board is lifting slightly as the rollers leave the board, wouldn't that leave a horizontal line or depression?

EDIT: Maybe adjusting the infeed and outfeed tables would help.

It does leave the horizontal step. You can see it in the pictures.

As for the outfeed rollers, I think you are right on. I just realized this morning that my outfeed rollers are adjusted with a preload. (It makes no sense to me to have them adjusted to just touch the board. They spring down and do nothing.) Mine are adjusted higher and that is why my carrier does not move when the rollers roll off of the board onto the carrier sides.

In my desire to make the carrier operation as simple as possible, I was biased and was quick to take the behavior of my machines as typical. This was a mistake. Even with the outfeed rollers adjusted high like mine, there are cases where it will not help. Short boards for example. I usually put my boards in the middle of the carrier, and so, I never noticed the problem.

Just to be safe, I am going to have to recommend always using the four shims. (I use them all the time with ACB to put under the board during measurement. Then I take them out and the board drops below the sides. The problem does not exist when the board is just below the sides.)