Workpiece Alignment ideas

[TomHackman]

Hello-
First post- please be patient.
After using our PRS Alpha for 4+ years, I'd like to make workpiece alignment simpler. I may be missing some simple solution. I am also likely adding a vacuum table in the near future.

I'd like load my sheetgoods against a positive stop for X and Y and know that I am in the right spot every time. We rarely change our zero for X and Y. We use a lot of 4x8 sheets of varying thicknesses and frequently cut all the way to the edge.
I have been toying with using 'bench dogs' of some sort that drop into holes on the X and Y zero lines. The other thought I had was guides on hinges that can be flipped out of the way when cutting along the zero lines.
In the past, I have set my spoilboard outside my zero lines for x and Y and cut a slot (1/4" wide by 1/8" deep) and aligned to the inside edge. It works ok but can be painful when I resurface.

I feel like someone else has to have a solution. Any advice would be greatly appreciated.

Thanks!

[MogulTx]

You could probably search Gary Campbell here or on Youtube. (see this vid: https://www.youtube.com/watch?v=wDlRTOG9B4M ). You can adapt the concept to your own needs.
Best Regards
Monty

[coryatjohn]

I cut the zero edges of my spoilboard to be the exact zero position. That way, to align a sheet or other material to the table, I just have to get it aligned with the spoilboard edges. Very simple. Very repeatable. Easily verified.

[TomHackman]

"You could probably search Gary Campbell here or on Youtube. You can adapt the concept to your own needs."

I'll take a look. Thanks!

[TomHackman]

Are you using a vacuum table? I guess my concern is the distance of the plenum from the edge. I don't have much first-hand vacuum table knowledge.

[waynelocke]

I use a vacuum table and side references.http://www.talkshopbot.com/forum/attachment.php?attachmentid=34499&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=34498&stc=1I replace the inside piece periodically and trim it to zero on the SB. I have very accurate 1/2" and 1" spacers which I use occasionally. The vacuum plenum is HDPE (I think) but I am going to change to a phenolic table in the next month for improved dimensional stability. I use 2 Lighthouse vacuum motors mounted under my shop with cooling fans on them. I can hold sown a 4 X 8 but rarely do. I often use sacrificial plywood sucked down and screwed to that or otherwise hold it to the plywood. http://www.talkshopbot.com/forum/attachment.php?attachmentid=34500&stc=1 As you can see these last a long time.I also have low density fiberboard spoilboard pieces cut for each vacuum zone and flattened in place for hold down. This works well for me.

[dlcw]

Here's my simple solution to X,Y alignment.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=34501&stc=1
http://www.talkshopbot.com/forum/attachment.php?attachmentid=34502&stc=1
http://www.talkshopbot.com/forum/attachment.php?attachmentid=34503&stc=1

Not shown, but there is also one that goes into the front of the table to align the X at the same point every time.

I used the CNC to drill the holes for the blocks. Made the blocks the old fashion way with table saw and drill press. Pins are 5/8" oak dowel wood. Has worked well for about 9 years now.

[TomHackman]

Don said-"Here's my simple solution to X,Y alignment.
Not shown, but there is also one that goes into the front of the table to align the X at the same point every time.
I used the CNC to drill the holes for the blocks. Made the blocks the old fashion way with table saw and drill press. Pins are 5/8" oak dowel wood. Has worked well for about 9 years now."

Thanks, Don- this is the general concept I had in mind.

[jerry_stanek]

I use slide bolts for the stops