Cutout problem ??

[Rick P]

The first cutout went fine...the second one was bad? Anyone know why that might happen?
My thickness total is 3/4". I am using a 1/2" carrier board with a 1/4" project board taped on top.
Could that cause a problem?...it worked fine first time.

[bergerud]

That looks like the mysterious X tracking problem which seems to randomly occur. I think this is the same problem which causes stair stepping on multiple pass cutouts. My theory is that cutting vibration can resonate with the brass roller and confuse it. I think that the further you can keep the cutting bit from the brass roller, the better. (The only "evidence" that I have for this is that it has never occurred to me since I started using my carrier bases.)

[Digitalwoodshop]

I agree... a problem with the X.... Could be head pressure... I know you used a carrier board, did it have 4 inches more of wood? So the board did not come out from under the rollers. Almost looks like the board came out from under a roller releasing the pressure on the board not holding it flat and letting the brass roller skip some of the board....

The only thing against that theory is.... Where did the Cut START.... With the end messed up the cut should NOT have completed to the starting point.... This is confusing.... AND the sample on top is up side down from the one on the board. Not a problem but the center of the U in the project is flipped...

SO.... this leads me to go in a totally different direction..... That the project SCALED and fit the project in the slightly reduced area.... This is a WAG.... a VERY WAG.... Very Wild AL Guess....

AL

[bergerud]

The only thing against that theory is.... Where did the Cut START.... With the end messed up the cut should NOT have completed to the starting point....
AL

Cuts always start in the x direction if possible, and so, if the cut starts on a straight line, it always lines up in the end (as long as there is no Y slip). It looks like it started at the bottom of the U in this case. Notice that, in this case, the cut started on a circle and did not actually line up in the end.

I agree that leaving the rollers would also explain the X tracking problem. I assumed he stayed under the rollers. (Note that the cut did not end properly on the first project either.)

[SteveNelson46]

I am not positive but I think I agree with Bergerud. If you look closely at both of the cutouts, none of the vertical parts are the same size and the overall width isn't the same either. I think it not only came out from under a roller, it also scaled.

[Rick P]

I think the problem was in fact mainly head pressure. There were a few things happening...a perfect storm ? It got very humid here in Minnesota and I had not put out my dehumidifier yet. Everything was a little stickier than normal. And I use that dust collector that mounts on the CW carriage...I had used a bungee cord to keep the dust collecting tube in place and I think that was applying pressure to the CW carriage, making it slightly cocked. I was not getting proper pressure on the board. Another possible issue was that I hit "Do Not Stay Under The Rollers" as I was trying to conserve wood. So, I did not have the extra 7"...my bad !! Last night I was able to cut out 3 projects just fine after correcting my "perfect storm" of issues. This had never happened before. I need to find a better way to hold the dust collecting tubing so it will not affect the up & down movement of the carriage. Thanks for the comments !!!

[DickB]

Rick, I cut a lot of 1/4" plywood. I suggest that you affix a 3-1/2" or wider strip to the end of your sled to avoid waste. I often use masking tape to hold the project board, but if I'm not careful the board can move slightly. With a project like yours it looks like you could easily place a couple of screws to secure the board to the sled.

[bergerud]

I think Al had it with the not staying under the rollers. As soon as a roller drops, the controller stops using the brass roller for tracking correction and switches to using only the x motor encoder. This and the extra stress due to having to push up rollers quite often produces results like you had.

[fwharris]

I think the problem was in fact mainly head pressure. There were a few things happening...a perfect storm ? It got very humid here in Minnesota and I had not put out my dehumidifier yet. Everything was a little stickier than normal. And I use that dust collector that mounts on the CW carriage...I had used a bungee cord to keep the dust collecting tube in place and I think that was applying pressure to the CW carriage, making it slightly cocked. I was not getting proper pressure on the board. Another possible issue was that I hit "Do Not Stay Under The Rollers" as I was trying to conserve wood. So, I did not have the extra 7"...my bad !! Last night I was able to cut out 3 projects just fine after correcting my "perfect storm" of issues. This had never happened before. I need to find a better way to hold the dust collecting tubing so it will not affect the up & down movement of the carriage. Thanks for the comments !!!

Yes not staying under the rollers will mess up a carving more times than not.

On your dust collection hook up, are you using the heavy standard dust collection hose? If so try adding a section of aluminum drier vent hose between the normal hose and your dust collection attachment. It is my lighter at the machine plus being metal is will add a bit more protection for static electricity.

[lynnfrwd]

Yes not staying under the rollers will mess up a carving more times than not.

On your dust collection hook up, are you using the heavy standard dust collection hose? If so try adding a section of aluminum drier vent hose between the normal hose and your dust collection attachment. It is my lighter at the machine plus being metal is will add a bit more protection for static electricity.

And will easily snap a 1/8th cutting bit.