Prs alpha out of square

[andre]

Ok, I spent tuesday wed thursday setting up and have been having fun. My table is perfectly square and leveled with a laser. The car went on without a hitch and road smooth and straight.
I cut a practice cabinet part 11.25 wide and it was out of square over 1/32 of an inch. very unacceptable. I've read material on squaring the x car, which I can understand if it became missaligned somewher between factory and my shop,
and what I am reading does not make much sense. Why would the car move out of suare when turning the power off and why would you need to resquare the car everytime you turned it back on? On a machinelike this that seems to be a malfunction. Any ways there has to be a way to square the car permanently. I think I will try adjusting the gussets on the x car like one post suggested. I would really like to here from anyone who is or has experienced this.

Andre

[richards]

Andre, try this experiment. Have someone hold one side of the gantry firmly against a block or stop so that it can't move. Then have someone else gently push against the other side of the gantry. My guess is that you'll be able to move it out of position at least 1/2-inch. A similar thing happens every time you power up the two steppers that are on opposite sides of the gantry. If one stepper jumps or stutters just a little as it turns on (it will jump to the nearest stable position) and the other stepper jumps or stutters in the opposite direction you'll have a gantry that is out of square. Believe me, I've tried to find a way to keep that from happening with my Alpha, but the simple, practical solution is to hold the gantry against stops on both ends as the steppers are powered up. It is simple and it works.

[dray]

The only way to make sure your x-car is square is to use a pencil in the chuck or cut a groove and square off of that. The tech support stuff is a buncha garbage never square off of sheet goods.

1. cut a groove down the length of the table (or use mechanical pencil in chuck)

2. Use a good framing square to square off of that and transfer line across your table

3. then plumb down with a level off of your x car and get marks and see whats going on.

Ultimately both steppers should be on same controller but most likely its out of square at the gussets

[srwtlc]

Andre,

I had the advantage of my table layers (MDF) being oversized (49" x 97") so here's what I did after pulling the carriage up against the stops and engaging the motors.

I cut slightly in around the perimeter of the top layer and then measured diagonally. I did this with the keypad, eyeing it down each edge and moving it with the arrow keys all the way around. I was off by a strong 1/16" to 3/32". I then moved one stop ahead (or back if that's your case) by half the diagonal measurement (clamped a block next to it, loosened it and placed a thickness gauge between the stop and the clamped block and retightened), turned off the motors, pulled the carriage against the stops and clamped it in that position. I then loosened the gussets, gave it a couple of love taps with a rubber mallet from the top just to help seat it (or comfort me) and then tightened it up. I then ran the perimeter again just a bit further in and measured again. I repeated this about three times until the diagonal measurement came out the same (I had to make sure that I didn't cut to much of my table/spoil board away so I just cut off a small amount each time).

Now, at startup, I will pull it against the stops and turn it on. If you use this method, you need to turn off the limit switches because you will most likely trip the Y in the process.

I didn't think that it would stay in this (seemingly torqued) position because of the ends being bolted tightly with the eight allen head bolts on each end, but it seems to have so far. I'll be keeping my eye on it for sure.

I think that the sloped edge is what is being flexed or moved slightly and then held in position after tightening up the gussets.

[drodda]

Why are we still using the very old "move your stop blocks" way of squareing the machine? You would think by now Shopbot would realize that this is a problem and have an adjustable stop block with a adjuster built in if they are still wanting us to hang off the back when we turn on our machine to make it square. This would cost maybe $10.00 for them to make and include with the machine and make it much easier to square the machine if they are not going to supply a machine that stays square in the first place? Just a thought?????

The loosen the set screw and move the block does not work if you are adjusting out a very slight out of square problem as the block will go right back into the same set screw make on the rack.

-D

[andre]

MAn this seems confusing. First if I have to push the car by hand, according to shopbot I need to unplug the cables from the controllers to prevent static discharge. Am I wrong? or does that amount of movement not matter? I thought the purpose of cnc was precision, why should I need to monkey around with such a procedure everytime I start my machine. So if i have this right I have to square the car manually with the power off and clamp it into place. then turn the power on so the steppers can lock in place. then drive the car to the stops and adjust them to the car. And from then on every time I start I drive the car to the stops and squares it or do I push it manualy to the stops and then turn it on?
I know when I was first testing the movements I hit the stops a few times and the stops were not even so the car jumped a bit on the one side. Maybe that missaligned things.

[richards]

If you stop the machine near the stops (about 1/2-inch away) everything will work as described. It takes about 2-seconds to pull the gantry to the stops. It really works - and it is simple.

[rustnrot]

1. This appears to be an issue with PRS as well as older machines correct? Or is this worse with the PRS machines as I cannot recall this being an issue before now.
2. Will pulling the carriage manually the last 1/2" to the stops cause a voltage spike and damage the motor drivers?

[thewoodcrafter]

Can't this be cured by making sure the racks are in the same location along the X?
Can't 1 rack be slid along the X after things are powered up to take the error out then retightened up?
Sure seems that if they are not lined up and are off by 1/4 of a tooth from each other it would cause problems.

[andre]

Roger are you pulling the carriage to the stops with the power on and if so does it just stick after you pull it?

[richards]

BEFORE powering up, pull/push the gantry against the stops and then turn on the power. Small movements of 1/2" will not damage the controller. (The problem will moving steppers by hand so that their shafts rotate is that a stepper - probably any electric motor - turns into a generator. Some control electronics can not handle electricity that is generated by the stepper motor. However, small-slow-moves of 1/2" will not do any harm.)

[jhicks]

Old problem but same solution. Unfortunate to hear this has not been addresses in the new model. Regardless, wether its a stop block, calibration gauge, pencil marks, or whatever. IT is extremely wise to set up a quick calibration method and check at minimum every time you start up, or leave controls on but still check before anything is run. If one experiences any kind of interruption, hogs too much or too fast and has a Botus interruptus, you better recalibrate or risk the piece(s)
Agree this is a terrible inconvenience but it is what it is so we just take the time to use our technique and live with it but wish we didn't have to.

[andre]

So again, when you pull the carriage to the stops with the power off will it just stick and maintain while you walk over to power on?

[dray]

I am unsure about the PRT but the PRS is connected to two seperate stepper motor controllers. I havent pulled up a any info on the stepper controllers but if they go out of square often I am thinking that if you were able to connect both x steppers to a single stepper controller this may help the issue.

Also I am unsure of how accurate the limit switches are but couldnt someone add some code to the SB3 prog and add a limit switch to both sides of the x carriage and just have it zero back to square?

I mean they are controlled independently.

It is a precision machine but the rest of the world isnt. there are many factors, how fast is the juice hitting the left steppet vs the right. How cold/warm was it last night for the metal to expand/contract.

I think instead of trying to make the world perfect try instead to make an easy solution to re square the machine.

[beacon14]

Danny is on to something. It should not be too hard to make an automatic squarer, as long as you have the ability to control each X motor independently. Some way to read the location of each end of the gantry (prox switches?) and a short program to move one motor by the difference in the two readings.

Can we move one X-motor independently?

[dray]

yes, they are on independent controllers. It may not be coded into SB3 yet but I looked at the board and they controllers seem to have the ability.

Also my SB3 is realllly really buggy are any of you out there coders? I refuse to call Tech support any more all of them except for "Chad"? have an attitude.

Instead of looking for a solution they make things waaaay more complex than they need to be and end up making you feel like a crumb for asking simple questions. I dont believe thats what Teds vision was. If they dont like their job get a new one.

I am unsure if the SB3 is open source but if it is I have a few friends that like that kinda stuff and together we could make a reallly cool shopbot GUI. LOL talking with the tech support is like those computer guys on Sat night Live "MOVE" lol

I think we can work it out in the community on our side and let Ted get rid of "undesirables". Give him some room to go back to basics.

If anyone can code a lil email me or something. My neighbor works in C ,Fox Pro, VB and a ton of other languages Im gonna bring a copy over to him along with a 6 pack and see what he can come up with if he has time.

This is the best way to get things done is to just do them yourselves.

My new SB3 prog slows waaaay down in corners about 10X more than I think it should and heats up my bits anyone else having this prob?

Thanks again Guys great group here!

[andre]

I'm quite aware that the world is not perfect nor machines but that is why we make allotments in design to make up. I think the idea of a second prox switch is so simple it might just work. So heres what I did today and it worked.
I figured out the adjustment needed and moved the stop until it was right. With the power on I directed the carraige to the stops until the reset tripped. I walked over and reset and things locked into square. I think this is what you were talking about.

[dray]

how did you add the secnd limit switch?
They would need to be programmed into the sb3 code to hit one limit on X then find the other or if it finds both at same location then 000

Im not an engineer just a simple carpenter so I may be wrong =)

[andre]

Sorry my message was not clear. I did not add a second prox switch. I thought it to be a great idea though. I just reset the stops until things were square and then drove the car to the stops until they both hit the stops and the reset tripped. I then hit reset and things stayed put in square. Tommorow I will figure out the exact location of the stops and set a daily routine to send the carraige to those points and reset. Anyone see anything I am missing?

[dray]

ohh I see. Wont that cause damage after a while?

[steve4460]

Hi Andre

I wouldn't do that , it couses to much where and taer on the gears and the electronics.
If you have the gantry square and then sutt down the bot , and nobody moves it in between , then when you start it again it should still be square. It could be that your out of square cutting is becouse of cutter deflection . How fast and how much are you cutting whith what type of cutter ?. What material ?.
Bot on
sv

[andre]

I guess i did not think about wear and tear and it make sense now that i think about it.
Its nothing to do with speed because I am cutting at 2"/sec with 1/4 upcut with .3 stepdown
through partical board. Are you saying that if I square it once that it will stay even when I turn it off?

[steve4460]

Hi Andre

I have been cutting cabinet parts on my alpha for quit a while and I have yet to find one that is out of wack . Also I have been cutting with a CMT 0.25 downspiral at 6"ips with 0.25 stepdown .
The downspiral makes a cleaner cut and less chip out on the topside it also pushes the sheet down so that my 6.5 Hp shopvac holds them better , with the upcut your lifting the sheet a little .
Yes it will stay if you don't move it by hand after it is turned of . You should never puch your bot around anyway since it can couse your drives to burn out and those are spendy.
Bot on .

SV
Ps: are you coming to this years camp shopbot MN again ?.

[srwtlc]

Unlike the older PRTs, I have noticed that the PRS Alphas (at least mine) lock in/out without any jerk or snap that would've normaly caused the older PRTs to rack slightly upon turning them on.

If it is cutting square and you don't notice the carriage "relax" when you turn it off, it should be fine when turned on again as long as it wasn't bumped out of position while off.

[fleinbach]

There may be more then one way to square the X-car to the X rails but at this time none is faster nor more acurate then using the stop blocks as Mike Richards explained above. Once the stop blocks are adjusted properly it only takes seconds to hold the X-car against the stops and power up the controller.

As for pulling the cars around with the power off, I was told it would not hurt the motors on the PRTAlpha and have moved mine manually sometimes several feet hunderds of times and they still work fine.

As for the issue pretaining to the X-car not being able to remain square this can be expected on a tool costing so little but capable of so much.

You can work on the X car making tweaks until it is perfectly square but the first time you make an error and the machine hits something it wasn't supposed too, or jumps off the rails, it won't be square again unless you take time to resquare it all over again.

[andre]

Stephan

I am planning on it. When is the camp? did they announce it yet?
After reading the article posted on the web site I got the impression that you had to square the machine evrtime. I beginning to see what everyone is talking about. Set the stops so when you can check and make sure, but under normal conditions the machine should stay square.
When I spoke of driving the carraige to the stops, I meant easing them gently til they stop. I figured slamming them into the stops would not be a healthy approach

I still don't see how you can hold the car and turn the power on at the same time unless your right next to the control box. I guess if you use the stops nearest the box you probably could with out using your toes


Thanks for all the help! Scott thanks for the time on the phone Sat. I will post some pics when I am fully set up.

[steve4460]

Hi Andre

The MN camp is on the 15 of September check here for updates. http://www.talkshopbot.com/forum/messages/11096/19551.html?1174673463
Bot on

sv

[andre]

Thanks Stephan

They dont mention place. Is that at foam carvers again?

[richards]

If I'm alone in the shop, as I usually am, I use a wooden clamp on the far side X-rail to hold it against the stop. The near side X-rail is directly above the control box, so I just hold that side again the stop when I turn on the power. It just takes a few seconds and then I'm set until I turn the power off (or I have a fault condition - rarely - which means that I need to re-square the machine).

[billp]

Andre,
Yes it will be at Foamcarvers again. We'll fill in more details in the next few months.

[gpari]

The stop block method works pretty good. There are many out there, including Gerald, that have made adjustable blocks with grub screws that don't work any better, but they sure are easier to adjust the first time.

I don't think the answer lies in two proximity sensors, they are pretty accurate, but not enough to square my machine. Plus the controller board sends a single signal to the two x-car drivers, so I imagine that driving the two independently would be a major feat (as I understand, you could "un-power" the motors from the software on the PRT's, but not on the Alphas).

My answer, when I get some time, is to mechanically force the machine to run square. Take all the flex out of it. This can be accomplished many ways, but the simplest (well, maybe not the simplest, but the most elegant and effective) I can come up with is with cables and pulleys. Very similiar to what is on a little Mayline drafting board. I've used this setup many times in robotics applications and it works very well. It could be hidden pretty well on the bot, so that you would snag the cables, the casual observer would not even know they were there.

Well, that's my $0.02.

As far as the shopbot customer support, it seems hit and miss. I've talked to a few that were really good, and some that I think showed up for work at the wrong building in the morning, "Dude, is it plugged in??".

Gabe Pari
www.socalteardrops.com (http://www.socalteardrops.com)

[ted]

Well on Gabe's suggestion that we use cables like those on drafting tables, I can't help but get a warm and fuzzy feeling thinking of those early ShopBots that worked exactly that way. I kind of miss 'em ...

But let me add my two cents on the squaring issue. I think we've probably overblown this one a bit in the sense that once your tool is set up square, it's probably going to stay square. At least unless someone comes by the tool and pushes one end of the carriage. As Mike pointed out several times up above, if you try, you can push one side of the carriage out of square by a half inch. That's because the motors and gearheads have plenty of friction and can hold the car out of alignment. Pull it a few times from the middle of the car and it will line back up about right.

But it is nice to know that, if you are in doubt, you can just pull the tool against the end stops and assure yourself that it is square. As long as it is near the end you pull it to, and you do it slowly, you will not damage the drivers. Then just fire up. You'll be square and stay square (and on another question above, your steppers actually do move in perfect sync and as long as they are not malfunctioning in someway, or the speed of light does not change, they always move identically).

The PRSs have sliding stop blocks that make setting the end stop location very straightforward. You won't need to pull against the end stops all the time, particularly if your shop is not busy with forklifts and heavy loads being moved around. When the tool is on, it is always rigidly locked square in position. So the issue only arises when the tool is de-powered.

Yes, as has been suggested above, squaring could be automated. If someone were interested the routine could be easily written in ShopBot's Part File language. It could probably be done as a variation of the current XY homing program. Note that this does not need to involve digging into the code of the ShopBot software, but could easily be done as a Part File. I imagine that the prox switches would work well for the purpose though you would probably want one on both sides. They are very accurate as long as they encounted with a slow and constant approach speed (the reason that XY zeroing is done in two contacts).

At the moment, you would have to dedicate a driver channel to this in order to separately control both motors (e.g. move one of the X motors to channel 5). But we have been pondering a system where we could selectively disable one or the other motor in order to make a small squaring adjustment. Certainly something worth pondering. But for my money, it seems pretty complex compared to occasionally checking to make sure the car is square by pulling it to the stops.

Ted Hall, ShopBot Tools

[ted]

On Danny's 'too slow around the corners' concern ...

A corner slowdown happens for two reasons: 1) If it's simply a square or sharp corner, look ahead ramping is telling the tool it has to slow down so that it does not bang around the corner too fast. To take the corner faster, decrease the number for "Move Ramp Rate" (acceleration) in [VR] (e.g. from .4 to .2 or if you are at .2 to .15 or .1). This make acceleration and deceleration happen over a shorter distance and thus you will not slow down as long; and, 2) Most CAM programs such as PartWiz round outside corners with an arc. This is true even if the corner is perfectly square (I know, it took me a while to adjust to this one). By 'rounding' the square corner, the cutter is kept in constant contact with the corner and this helps reduce chipping and uneven pressure on the cutter. But it all means that there is actually an arc that the cutter must pass through in rounding the corner, the bigger the cutter the bigger the arc. So, this kind of corner is not a simple start and stop. The arcs, if relatively small and the tool going fast, will be executed at the tool's defined Ramp Speed. So, you can increase the speed of corner rounding by increasing XY Ramp Speed, the first parameter of [VR] (e.g. you might go from .4 to .6 or .7). In addition, you can also make the same adjustment to Ramp Rate described above to move in and out of the rounding area more quickly.

Ted Hall, ShopBot Tools

[dray]

THX. Makes sense.

[bahed]

1/32" error over 11-1/4" = 0.0028

That looks about what the reported positional accuracy specs for a PRS Alpha (0.003) .....

.... am I missing something ?

[stevem]

Yes, you are. 1/32"=.03125"

[andre]

Ted,
After hearing many discussions on this and listening to what you say I realize that this looks like a once and a while thing you should check and that if you have it squared once and set your stops you will have a permenant reference. I think when I first read the instructions I got the impression that you had to do this evertime you started the machine.
Maybe shopbot could simplify and clarify the instructions and call it "first time squaring of yz car and z axix"

[gpari]

I do it everytime I start my machine, it takes about 3 seconds, literally.

The machine is parked .5" from the stop blocks before shut down and in the morning, I pull it against the stops, and switch it on. DONE! I know it's square... No guessing or wondering if anybody bumped it while I was gone.

Gabe

[andre]

gabe
you must be using the stops right next to your control box.
when I tried that with the power off the car never locked in it went back. The only way it locked in for me was to ride it to the stops with the key board (gently)and reset the switch. then it locked in and has not moved yet, I think

[harryball]

I've gone weeks without checking or resetting square. Unless I'm the one moving the gantry there are very few other people who might move the tool while it is off. However, having actually cut while off square I understand how you would want to verify the square at every startup to avoid the destruction of expensive materials, especially if you are not a one man shop.

When I can make something simple and effective, that's how I like to leave it. Going with a complex solution can be fun and eventful, but in the end what have you really gained? Gabe's solution takes a few seconds during the start up when you should inspect the machine anyway. The added cost, complexity and learning curve of an automated square system doesn't seem to offset any real hardware shortfalls or lost operating time.

It seems to me, the biggest advantage could be gained by making the initial squaring proceedure and mechanism simpler and more fine tuned (such as the adjustment screw). Another approach might be to add some type of calibration pointers (think of the rip fence on your tablesaw) to each side of the gantry. Zero your XY, square the gantry and lock it down. Zero your pointers and from then on when you jog home a quick look at each side tells you if you are square.

As for me, I don't worry about it unless I have reason to believe the gantry might have been moved.

Robert

[dray]

I would rather push a button to square it!! lol

But Ill re-square again then set blocks again and give that a shot.

It bugs me when im cutting big parts not knowing if they are square until im they are done.

The other thing I was going to ask is.. Cant you tell the cnc to start at zero do a 45 (maybe 2')
then have it run square back to zero and tell you if it counted the exact amount of steps its supposed ot have? (I dont know how to code my cnc yet)

[bahed]

Steve, I have a calculator too, and can determine the decimal equivalent of 1/32.

I thought that the thread originated with Andre having 1/32" error over 11.25 inches. That amount of error is pretty small as I stated in my previous post: 0.0028 in/in. Measurement error at that scale is likely more of a concern.

I would like to understand a little better not - how to square up the Bot - so much as to WHY in this situation.

[gpari]

In my application, 1/32" over 11.25 inches is HUGE! That's almost 3/16" over 60"

I'm happy when I'm at less than .010" over 60", which is not too hard to achieve, just takes patience on setting up your stops.

Everyones application dictates different degrees of accuracy/precision. I came from having my parts outsourced on a half million dollar Biesse to doing them myself on a $25K Alpha. So I'm trying to fill some pretty big shoes with my bot, but it's working just fine with a little bit of attention and care. If you can afford $2500/month to lease a "real" CNC, then you wouldn't have to do any of these "annoying" little rituals. But then again, when the thing gave up the ghost, you'll be down for days waiting for the tech to come out and un-freeze a froze gremlin somewhere.

I've modified my bot a little, time and money well spent, and currently I'm happy. Would I swap it out for a $250K machine if I could, yes, but only if it was fiscally responsible.

I guess you just need to find where YOU need to be and get there.

Gabe

[waynelocke]

Bret,
You have a misplaced decimal. As Steve pointed out, 1/32" = 0.03125. The error is 0.028, not 0.0028.
Waune

[andre]

Brett
Where to begin with square?
The most crucial step in cabinet making is milling and dimensioning. If your cabinet box parts are out of square they will be twisted when you put them together. multiply 1/32 times 2 for lowers(24 inches deep) and then by four for the two ends of each. Then try to put an inset door on that box and see what happens. If all your making is individual widgets or signs maybe its not that crucial but for cabinets and furniture its absolutly crucial if you want your pieces to sit straight and hang straight. As far as squaring routines, I agree the simpler the better.
I love my new cnc and Shop Bot has a great staff that is there every time I call and walks me through my issue. The reason I chose shop bot was the community of users and this Forum, and the company itself. I like their philosophy and and all the resources available through the web site.
There is obvioulsy a lot of opinions on this subject, I had no Idea when I started this thread.

[richards]

Just for kicks, I powered up my Alpha, which had been sitting idle for four days, without first pulling the gantry against the stops and then ran the C3 routine to zero the X and Y axes. Using three pre-set combinations squares, one for the X-axis right side, one for the X-axis left side, and one for the y-axis, the X-axis left side was out by 0.010" inch. That is, I could insert a 0.010" feeler gauge between the blade of the square and the frame of the machine.

I think that having a 0.010" rise over an 84" run is within tolerance. However, to reduce that error to 0.00" I could have spent an extra 10 seconds and pulled the gantry against the stops - just to be totally safe.

Before I accurately set the stops to use Frank Leinback's method of squaring the machine, which is the method of pulling the gantry against fixed stops that we've all been discussing in this thread, I pre-set a separate combination square for each axis. The method was to start with the machine totally squared and all steppers on, and then adjust the three squares so that the blade of the square was against the movable gantry and the body of the square was against the non-movable part (frame for the x-axis and x-car for the gantry). After tightening the locking screw on the squares, I marked each one with a permanent marker so that I would know which axis position it had been used to gauge.

Even though I use Frank's method to start up the machine, I still cross-check with the squares when I'm cutting parts that have to be 'true' and 'square'. In my book, taking an extra minute or two to start up in the morning beats explaining to a customer why his parts don't quite fit.

[richards]

I just received an email that references an old thread on the forum, that shows a simple modification that Gerald D. made to his machine back in 2001 to make squaring things up both simple and quick.

http://www.talkshopbot.com/forum/show.cgi?tpc=26&post=2850#POST2850

[jay_p]

Bret,
For what it is worth:
If I divide 0.03125" by 11.25" I get 0.002778 just as you did. If I divide 1/32" by 11 1/14" I obviously get the same. It seems pretty straight forward to me.

Jay

[richards]

Bret et al,
I think that we're talking about two different things when we cite 0.003 positional accuracy and 0.03125 rise over a 11.25" run.

The 0.003 figure (positional accuracy) would be the difference between where the controller had commanded the axis to be and the actual position of the axis. That deviation would be due to factors beyond the control of Shopbot, such as the 5% per step non-cumulative tolerance on most stepper motors from Oriental Motor and the backlash in the gearbox used with that motor and the tolerance of the spur gear from tooth to tooth along with the tolerance of the rack from tooth to tooth. In short, adding up all the tolerances for the stepper motor, the gear box, the spur gear and the rack would give us the worse case positional accuracy deviation from things that are out of our control. Of course we would have to add other factors into that formula, such as the additional deviation caused by dirt and grime accumulation on the spur gear and/or rack and the flex of the cutter.

The deviation of rise over run is totally within our control. It only depends on having things true and square.

[hippo]

Jay,

Your math is right, but I think you guys are talking at cross purposes.

The tolerance for the machine is that you should be able to move it anywhere on the table and have it within about .005". NOT to move in anywhere within a 1" square and have that kind of accuracy. Because at the opposite end of the table that small per/in error will add up big time.

At least that's how I understand it.
-Dan

[andre]

Am I the only one who can't find the instructions for squaring the Z to the table for the prs alpha?

[dray]

Here Andre use this. PDF

The directions put out by shopbot are over done by 10 fold (if you can find them). They are telling you to use a square piece of wood (if your table isnt square its not gonna make you one. Sheet goods are NOT square either)

Also it says to measure corner to corner and make sure both are the same etc. The problem with that is that in order to get it perfect you need 2 people burning an inch on one side of the tape and it just makes things waaaay too complex for such a simple operation. You can hook the tape in the center but then worry if the end of your tape was in the notch or which piece of the X was outa square etc etc etc.

Those guys are waaay too smart to figure out simple tasks.

Heres a 2-3 step process you can do by yourself and have it 100% accurate I dont care what the engineers say. Everytime I get on the phone with them they over complicate simple tasks. Real world is alot different than their Cad. Use the PDF I attached



squaring.pdf (http://www.talkshopbot.com/forum/messages/312/squaring-19889.pdf) (34.8 k)

If you need any help Im always avail on my Cell: 949-293-8318

Danny Ray
www.drayconstruction.com (http://www.drayconstruction.com)

[fleinbach]

Danny,

Your method has merit but if you don't mind I'd like to add to it.

When using a framing square it is a good idea to make sure it is truly square. Many brand new right off the rack are not. It has been about 2 years since I last purchased one and at that time more then half I tested while at my suppier where out of square.

Step 2 would be simpler if you omited the levels and moved the bit just off the table and made your measurements off of it along the Y axis .

[andre]

Danny and Frank thank you
I am actually looking for directions on how to square my router to the table, the z axis. Thanks to this forum I am working on squaring the xy car but now I need the z squared and cant find on thing in the manual that tells me. The one part in the manual that says " maintenance xyz adjustments" manages to take up 2 pages and not tell you a thing on how to actually adjust the darn things. Who wrote this manual?

[andre]

Just talked to Sctott at SB
On the prs Alpha there is no squaring routine because the z is supposed to square at factory.
But I am supposed to surface part of my table first and then check for square??
I have a manual that still has prt directions in it that tells me I should have squared the z first before surfacing. ( do you see where I am going and have been?)Any ways I am going back to the shop this morning to surface part of the table and see where that puts me.

[srwtlc]

Andre,

If you haven't surfaced off your table yet, try this first. Take a small level (torpedo) and check for perpendicular on both sides of the spindle/router to see how close you are. Mine was so far off in the XZ direction that I had to loosen the eight end plate bolts and the gusset bolts and rotate the beam backwards as far as I could (I had to gain almost 0.125"!!). I wouldn't use this method if you are off by a small amount though.

If you're off by just a little, loosening the spindle/router and tipping it slightly along with some shimms should get you close. Once you get it close, then surface your table. After surfacing, you can read the cutter marks on the surface to see at a glance if it's cutting flat or with ridges. To fine tune, make some sort of a trammel/dial indicator that you can chuck in the collet and spin it slowly by hand while checking to see that it touches or reads the same all the way around. Use a piece of something flat on the table to read off of (a sheet of glass works good).

I had to add some shims at the bottom of my PC mounting plate to tip it even further than I did by rotating the beam. You could use some precision shims on the v-rollers instead, but there isn't much for length on the lower bolts to do that and I needed to gain too much. As for the YZ, you should be able to get some adjustment by loosening the bolts for the spindle/router and tipping it one way or the other.

I would consider my XZ out of perpendicular to be extreme and should have been caught at the factory in the setup jig. Once I get a spindle, I'm going to be a bit concerned as to whether I will be able to further adjust the spindle as I don't think shimming between the housing and the Z column will be acceptable due to the fact that it is bolted top, middle, and bottom.

I'm sure that loosening the beam to adjust as I did completely negates ShopBot's setup in their jig, but I had no choice.

[andre]

Scott
I could not have set it better and that is exactly what I did. Now I have shims sticking out of my router harness which is going to bug the jeepers out of me. And it still is not perfect. MAn I hope they fix this, all they need to do is make the harness itself adjustable.
Every thing else I manage to square up. I cut my first practice sheet of cabinet parts and things were good.