Sled size and Clear Board Sensor message

[DianMayfield]

I made a sled that was about 12 inches longer than my project side rails. Incase I need to modify the design I wanted some flexibility.

The sensor measures the width just fine, but when the rollers fall off the end of the project, I get the clear board sensor message. Does the base need to be the same length as the side rails?

[bergerud]

Does the base need to be the same length as the side rails?

I am not sure what your setup is but, the rollers have to drop where the board sensor expects to find the end of the board.

[Digitalwoodshop]

Yes, the sled base and side rails should be the same. The real problem here as I see it... the rails need to have a end cap so the board sensor can see the sled rail edge the moment the roller drops. If I got your design correct... A Picture might clear it up... if I am wrong.

AL

[cestout]

You need a block of wood at each end the same thickness as the rails and at least 3 1/2" long. The sensor needs to see the board after the rollers fall off for 3 1/2". The rails can not extend beyond the end of what the machine see as the board.
Clint

[SteveNelson46]

I usually use a piece of MDF that is the same thickness as the project and at least 7" longer and 1" wider for my sleds. Then use the Carvewright to cutout a rectangle in the center that is slightly larger than the project . Then I mount it to a piece of 1/2" MDF. Using this method the sled can be used many times for similar sized projects.

[DocWheeler]

I believe that Clint's answer would solve your problem as you need "start/stop" points on the sled for the sensor that seem to be missing from your description. I do, however, disagree with Clint about their size. The sensor needs only about an inch and three-eights to function correctly. The three and a half inch "end-piece" is only necessary if you want something to butt your board against for "stay under rollers".

I personally use these smaller end-pieces so that I have room for using screws and washers to hold the ends of my work-piece.
80240
The two wood pieces screwed to the sled at the top and bottom of the work-piece were because I had four pieces to carve and this simply centered them in the Y direction. I do not recall why I wasted so much purpleheart, that seems so silly at this time!

Measuring the width of the sled can be done anywhere on this sled since the rails are less than 1" wide and and at 1" (Y direction) from the top rail the sensor finds a void so it goes to find the other rail. If the individual rail is 1" or more, it will simply consider the rail to be the entire sled/work-piece if it then finds a void.

As you can see, my end-pieces consist of a fixed 3/4" strip and pieces of scrap I either attached with fasteners or tape simlpy to get the necessary 1-3/8" for the sensor to see after the rollers drop off the end of the sled.

I ran across this picture while searching for one to show how I use screws and washers in a grove in the end of the work-piece be running in through my table saw. That sled is still in use but it needs to be retired because of all of the screw holes and carved places in it now.

[DianMayfield]

Thanks everyone for your input!

I was trying to decide on whether I would add three more blocks in length, as the whole thing felt pretty heavy and was concerned about the x drive wear.

The two blocks on the end are my 3.5, and I said no to stay under rollers. But the base extends 13 inches further than my side rails... in case I went that extra three blocks long. When it got to the end of the side rails, I got the error. Just to get through the set of dice, I held three blocks against the end of the project for the rollers to ride on while it measured :)

[bergerud]

Having the base extend longer is fine. (This is the same as the UCB.) I think your problem is simply that the sensor is confused by the poor edge between the blocks. Try a couple of layers of masking tape across the crack between the blocks or use a single piece of wood which gives a straight edge.

[DianMayfield]

Thanks Dan, that makes perfect sense. I bought the UCB, just haven't gotten around to building it.. it did inspire the 4x4 carrier :)