Board keeps "walking" away from edge

[djarboe]

Attached is my design. The board is 48" long, which leaves plenty of room so it will stay under the rollers. I've measured is several times, and it is dead on 48". The CW thinks it is a little shorter, but the ratio is only off by 0.3%, so I told it to ratio the carving. I also told it to keep the board under the rollers. I've also tried telling it not to keep the board under the rollers.

Anyway, I noticed that as the board goes back and forth during measurement, it is moving away from the fixed fence with the encoder. I have a precision straight edge, and the edge is dead on straight. when I checked it.

The only thing I can think of is that the movable fence is not tight against the other side of the board. I left this a little loose, since the other side is still a mill cut edge.

Should I cut it just enough to get a straight, parallel edge with the other edge?

Any other ideas would be appreciated!

I got up early this morning to get the 11 hour carving started, and ran into this snag.

Dave

[Bigtyme]

Given that your design says the board is 48" in order to "stay under the rollers". I believe the board should be 48 plus 7" for a total of 55". another thought is ...are the edges of the board parallel? I have had this issue before and found it to be the edges needing to be parallel....

[djarboe]

48" should be plenty long, since the actual carving is only 38.5 inches long, centered in the 48" board. Will try cutting the other edge parallel to the "working" edge.

[Bigtyme]

I agree about the actual carve length, but your board setup shows the length at 48" so that's the length the design uses even with a shorter carve... the design would have to be reduced by 7" to account for the true length of the board being 48"

[bergerud]

I do not think it matters a whole lot how parallel the two edges are as long as the sliding plate does not bind. The edge against the squaring plate, however, must be straight. If it is not straight, it will push away from the plate. If that edge is straight and the board walks away from the squaring plate, something is wrong. The squaring plate may not be square with the belts. Sandpaper belt may be rolled up?

As for the length of the project, it is taken to be the length of the board in Designer. Make it a little less that 48" in Designer and choose not to stay under the rollers and you will not have the scaling problem.

The outline of the piece should not be two separate bit paths. There will be no tabs. The outline should be a single cutout path with tabs.

[Digitalwoodshop]

First question is what belts do you have? IF you have sand paper belts then one or both of the belts are rolled under causing a up hill down hill situation letting the board walk away from the brass roller. "9 times out of 10 a user will respond back, NO the belt is not rolled under..." And a few times I would see a message... "wow.. it WAS rolled under" later... It is very hard to see....

Next up is head level.... A HIGH Bit Plate side of the head and the board will walk away from the keyboard side... To check head level.... place a board on both sides of the machine with a strip of paper on each board. Crank down and tug on the paper. One side high, the paper will pull out. OR use a bit to touch the board and read Z Data.

And it is lucky the board did not cut... as selecting stay under the rollers with a physical board and a designer board the same length would result in a scalled down by 7 inches carve AFTER hours of carving. You should review the use of "place on end" and end the madness of the machine measuring the board twice just to center it on the board.

AL

[djarboe]

Well, cutting the other edge worked. It allowed me to slide the moving guide next to the board, and now it tracks just fine. I did have to tell it not to stay under the rollers so it would measure the board length correctly. It was still off, but only by 0.002%, so I'll just allow it to ratio the carving, since that small error won't even be noticed.

Thanks for all your input!
Dave J

[Bigtyme]

Glad it worked out....

[lynnfrwd]

Actual carving size is always the smallest, virtual board size is next and actual board size is largest. If you built the 7" into your design (virtual board) then do not select stay under rollers (it will automatically). If your actual board is 48" and the machine measures it at 47.9999, then it will ask to shrink down to fit.

If the board is walking you may also want to check your head pressure.

[djarboe]

The walking stopped once I cut the opposite edge parallel to the main edge.

What do you mean by the "virtual" board size? You can tell I'm a newbie!!

[bergerud]

Virtual board refers to the board in Designer.

Crank the head of your machine near the top and compare the sides to see if it looks level. Go up just under the flats of the posts. (I wonder since it sounds like the walking was caused by the right edge of the board not being parallel. Maybe it is getting more force on the right side than it should.)

[johnsonswamp]

A vast majority of the stuff I cut out when I used the machine was 48"+, my machine is VERY picky with boards that long so I learned to run them through the table saw to square it up and put tape on roller edge before even attempting a carve. I have had some boards from the lumber yard and big box's be off by 1/4" width in spots and/or on one end. Without running them through saw 1st mine would walk nearly every time. Head pressure being right becomes very noticeable on longer board cut outs also. I got to where I'd make the machine measure 2-3 times to ensure board was staying lined up before letting it cut. It gets brought up a LOT, but if you have sand paper belts and doing lots of long cuts do yourself a favor and cut 1/4-3/8 off the inside edge as that sucker can and will roll up on you quickly.

[lynnfrwd]

Also on long boards, check your outfeed tray height and then anything over 3' needs additional outfeed rollers. These must also be a the correct height, so that the board does not "lift off" of the tracking roller when it hits the outfeed roller. The 7" rule is very important in carving & cutting a long board as it can "lift off" of the tracking roller or "tilt" when it pops out from under that 80-90 lbs of pressure the rollers are holding it down with.

Long boards can be done, but you need to be aware of potential points of failure. The longer the board the more potential for miss-tracking.

Heavy duty traction belts and TAPE will also help improve the odds of good tracking!

Who used to say "It's all about the roller."?

[Digitalwoodshop]

Also on long boards, check your outfeed tray height and then anything over 3' needs additional outfeed rollers. These must also be a the correct height, so that the board does not "lift off" of the tracking roller when it hits the outfeed roller. The 7" rule is very important in carving & cutting a long board as it can "lift off" of the tracking roller or "tilt" when it pops out from under that 80-90 lbs of pressure the rollers are holding it down with.

Long boards can be done, but you need to be aware of potential points of failure. The longer the board the more potential for miss-tracking.

Heavy duty traction belts and TAPE will also help improve the odds of good tracking!

Who used to say "It's all about the roller."?

Who is on first.... ? :)

[Bigtyme]

I carved a 10 foot long oak 1 x 12 earlier this year and it was all about the right support. I was very nervous about the long carve and actually carved the same size board out of pine first. They both came out well and I know the machine can handle them as long as they are supported properly...

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