PRS Standard Buddy 32 Spoilboard

[ky_trikes]

I was working on a friends Buddy last night and had problems with the X proximity switch tripping at about 23.75". At that point the rack is out of travel, save for a tooth or two. In the negative X, there is about 1.25 of over travel before triggering the proximity switch. The spoil board was cut to match the aluminum table; i.e. the sides of the spoil board are flush with the edges of the aluminum table in the X direction. 0,0 is set at the front right corner.

We want to set his machine up so we have less travel in the -X, and more travel in the +X. The only solution we can come up with is to shift the spoil board about 5/8" in the -X, but if we do that, it will obviously hang unsupported on the -X edge.

So, we are wondering what we are missing? How do others have their spoil boards set up? Do you let it hang out past the edge of the aluminum table on the -X edge? Please help us out.

[gerryv]

I have the same situation so watching with interest.

[Brady Watson]

Although not for the faint of heart, you can pull the table, strike a centerline mark for the tapped bolt holes for the rack, move the rack in the desired direction, mark, drill & re-tap the holes for the rack in the AL plate.

Other than this, you can shift the spoilboard, remove the table stops in hopes that you can gain that extra 5/8" OR see if you can go end for end with the AL table and see if that gets you the additional travel.

-B

[dana_swift]

Also.. remember that the prox switches have two functions, one is to detect that the system is "out of bounds", the other is to locate 0,0 automatically. If the "out of bounds" is outside the spoilboard, and the table had not run off the tracks yet, that can be just fine. All that is necessary is to tell the C1 command the offset between the prox switches to your actual table 0,0.

Just a note, I have measured prox switch repeatability, which seems to be around +/- 0.002". So just using the prox switches gets a decent 0,0 for the table with no effort at all. I have measured my table at length, and checked Gary Campbells table with a quick check last February. It measured the same, those are the only two sets of prox switch I have checked. "your mileage may vary".

To get a high precision 0,0 you need to "center in a hole". There is a routine provided with the shopbot to do that. For really fancy zeroing 3 axis in one operation, look into the super-zero.

D

PS- to measure prox switch repeatability, I wrote a little SBP file. If anybody wants it I will happily share. Its just the C1 command without setting doing the Z2 at the end. So you read where the prox switches set the zero location compared to the first time.

[bob_dodd]

If I understand correctly , there is part of the spoil board that the router bit does not reach. You could loosen the bolts on the gantry , & slide (on the aluminum side rails) it in the direction needed to gain the added movement

[ky_trikes]

Thanks Brady. Yes Bob, you understand correctly. And I understand what you are saying, but I think shifting the spoil board has less potential problems.

[ghostcreek]

Had same problem on my BT-48. I tried flipping the aluminum plate, but did not gain enough (interesting it is 3/4" of an inch off!). So I measured, marked, worried and then moved the gantry. Being very careful, and squaring everything, I have achieved my X-O right on the edge of the Aluminum plate. I would only reccomend this if you feel comfortable resquaring the gantry. Hope this helps. I am still concerned that at least two Buddy's are out by 3/4"?!

[erik_f]

When my BT48 with the aluminum table showed up I had the same problem and had to move my gantry, like Bob suggested. Squaring was a bit of a pain in the asteroid. I was upset that I was going to have to undo the factory "squareness" but found that the gantry was out of square and in the wrong place from the factory anyway. I scribed the original point for the gantry and then moved the gantry based on the scribe...then used a rubber hammer to bonk the gantry into square. I found (at least for me) that I did not have to tighten the bolt that hold the gantry down as long as I made nice easy passes. Also...once I had things pretty close, I lightly tightened one side down and just gave the other side the bonking. So the process goes like this for about an hour after you get "pretty close" to square. Bonk, cut, measure. Bonk, cut measure. Bonk, cut, measure...call SB and swear at someone...Bonk, cut, measure

[bluecollar]

Hopefully this thread is still active.
Dana: Regarding your June 7 7:36pm post, I'd be interested in your repeatability code. I'm working on creating assembly jigs for some projects. See the attached picture.
The jigs mount to the spoil board with recesses to align the individual blanks. The 4 red holes at the corners are 1/2" through holes which are intended to align the jig to the spoilboard using dowels. Within each recess there are 1/4" alignment holes which allow me to align features on the front and back of the blanks. These are cut through the blank and into the jig. After cutting one side of the blank, I insert 1/4" dowels and flip the blank in the Y dimension, keeping the X-orientation constant. This way the front and backside cuts are aligned.
My problem is with the machine zero getting off when I reset it to the center of the spoilboard for a small project. When I re-mount my jig, I would like to have the machine XY origin repeatable. To date, I haven't been using the C1 command since I don't quite trust the proximetry switches yet. If it's within the +/- 0.002" you state, that's more than sufficient.
Again, it's one more thing I need to learn to improve my skills.
Regards,
steve

[bluecollar]

Hmmm. You'd think that when I pressed "Upload Attachment" it would work. Let me try this again. Looks like the original was too big.

3587

[dana_swift]

Steve I have attached my "check limit switch repeatability" test code.


Limit Switch Repeatability test

3588 (6.3 k)

Put it in the "Custom" folder under C:\SbParts\Custom. Be sure you are not using custom21 for some other purpose, if so, rename the file appropriately.

This comes with my standard disclaimer- I don't support it, and don't even claim it has value for anybody else. Use at your own risk.. Study it to see what it does, its just a modified version of the XYZero routine.

Enjoy!

D

[cowboy1296]

my buddy 32 standard and 4 ft power stick are at least a month away from delivery and i am still fumbling around learning what i can. based on the equipment i have coming i assume i will need two spoil or sarcificial boards. i am only assuming plywood but what deminsions do i need including thickness.

[ghostcreek]

On my Bt-48, bottom board is hardwood plywood, and the top/spoilboard is MDF, which allows me to surface the table.

[kartracer63]

Rick,

I received my BT-48 in December and it came with the plywood table already in place. All you should need to do is mount the MDF spoild board to the plywood and you're good to go.