First installation - Installing X-car

[walnutman]

Hello all. Ive been lurking for a while awaiting by ShoBot. Just got it a few days ago and am in the process of putting the table together. I ran into my first problem, hopefull my last, an didnt want to wait til Monday to call for help. Here is my issue. I got the X-car all set up, with the v-grove bearing lined up with the v-grove channel on the x-rail. When I role the car, one of the bearings on one side stops spinning for several inches, and then starts spinning again. using a very accurate depth gauge, I noticed that the area whre the bearing stops spinning has a slightly smaller dimension between the rail and the top of the grove then the other portions of the rail. I can actually see a gap open up between the bearing and the rail grove as I move the car. has anyone had this problem. I dont see anyway to adjust for this.

Thanks for any responses in advance. This is a great forum.

Jeff

[andre]

YOu may have to shim the rails up where those gaps exist. Also, when you have things running you will have to square up the car to the rails so you cut square. ( search the forum for squaring your car. ) at that point you will re seat the car to the rails and the wheels sould roll flat. You are probably saying to your self What?! but read the articles and comb the forum, and you will see. This is how you learn the machine and make it yours

[andre]

Also
make sure your table is dead level and flat and square. Use a laser level if you can. Check that first because everything builds from that.
I have been running mine for about 2 months now. It took me a coulple of weeks of tweaking to get just right. Have patience.

[walnutman]

Wow, thanks for the quick response. i'll take a look at the post regarding squaring the car. What type laser level are you refering to? A transite type tool? Im not apposed to buying a level if it helps me be sure its all set up right. Thus far I have used tape measures and home made story stick type jigs.

[myxpykalix]

Go to BigLots I bought 2 laser levels there for $5.00/ea. that have a magnet on the bottom and a holder and will allow you to turn the beam vertical or horizontal. Hers a pic:
http://www.talkshopbot.com/forum/messages/312/20759.html?1178502925

[weslambe]

It's worth a couple of hundred bucks to buy/rent a transit to get your machine set up correctly every time.

I haven't bought one yet because my brother is a jig/fixture man at Goodyear aviation and has been able to come and set up my machines. With the price of gas, it will be cheaper for all concerned just to buy a descent one from the big box store.

With a transit you should be able to shoot various places around the machine to check for level and sags etc...

I was amazed at how bad my job of levelling was when he came the first time with his work transit. I was way, way off and I was using laser levels and a very nice digital 4' level.

Maybe 300.00 bucks for one but once you buy a vowel it's yours to keep.

[harryball]

A clear plastic hose with food coloring in water makes a very effective low tech but highly accurate leveling tool.

[srwtlc]

Jeff, like Andre stated, you may have to shim under those areas where the wheel loses contact with the rail. I had the same issue on one side and if I just loosened the allen head bolts in that area of the rail, I would get better contact. I shimmed and rechecked until contact was consistent throughout the travel.

[fleinbach]

Jeff,

While there are lots of ways to skin a cat so to speak I quess I will put in my 2 cents. I am a contractor with all the latest and greatest tools out there to include several laser levels costing several thousand dollars. But when it came to straightening my X rails I choose first my eye and finaly my 8' level used primaraly as a straight edge. I have the 14' X rails and by looking down the edge I can get alignment with no more then 1/16" descrepancy. Next I put my 8' straight edge on and adjust and shim.

You do not have to be concered about level while straightening. Once the rails are straight then you can level the table. Getting the rails straight before leveling will save time and not require unnessacary shims.

My 8' level cost $80.00

[andre]

Jeff
you purchased the PRS correct?
the two rail need to be on the xact same plane feild. a regular level would work but a rotary laser will tell you for sure. Cut 4 blocks the same size and put a pencil mark on all four. place them on the rails before you place the x car and run a laser around and adjust your legs until all pencil marks line up to the laser line. Do this with the level in the middle of the table with the pencil marks facing in. I did not have to place one shim on my prs alpha rail guides. they are really flat and true.
When it is time to suare your car, I can help walk you through if you would like, once you do it, some of those gaps may dissapear also.

[walnutman]

Thanks for all the replys guys.

Andre, I got the PRS Standard machine. I guess Im thinking like you. I went to Big Lots to get a laser level as Jack suggested and saw a 360 degree rotary laser for sale. I thought of using it similar to your suggestion. Although I did not think of the 4 blocks idea. Thanks for that. I purchased it and plan on using it today to try adjust the rails. Any suggestions you have on squarig the car would be great. Im not there yet, but am open to any help I can get.

Thanks again guys for all the help. It has really helped with some frustration that was building.

[walnutman]

Ok, Now I am getting frustrated. I have got the rails straigt, level and equally spaced. I had to use several shims on one side. The v-grove in the bearings run directly over the matching grove on the rail the entire length. However, even thought the rails are level with one another (i used a 360 degree laser level referenced off of piece of marked brass stock) one bearing raises up above the grove on a small area, about 1 foot, on one rail. Shims would not make sense here because the rails are already level. I tried loosening the bolts on the x-car that hold the angled bracket and clamping the x-car down to the railand then re-tightening, hoping any small amount of play in the bolt holes would line up the car. i did not work.

Any words of wisdom from all you pros. I have this entire weekend to set up may machine but am stuck here and dont want to proceed until its perfect

[denver]

Jeff, what you describe sounds a little like what I ran into with my machine. On mine, one wheel would slip mostly, but catch in a few places. It was just slightly higher than the others (or the others were lower). I propped up that corner slightly, then loosened the wheel bolt and pushed the wheel down while retightening the bolt. After that all four wheels made good contact, and I couldn't hold any wheel from turning while moving the car.

However, later on when I was checking vertical alignment of the spindle, I found it was farther out on one end of the Y travel than the other, so I had to make another slight adjustment on that corner.

[andre]

When I squared my car The wheels were a little off. I loosened the gussets on the aluminum rack. I then tapped the blue arms down until the wheels sat in place and then I retightened.
Know things are square.
Jeff, if your table is leveled and square, I would suggest to move on with the assembly and get the car moving and study how it moves. Try lossening the gussets and tap down with a rubber dead blow until things seat them selves and then retighten. Then run a cr routine as big as you can and then measure corner to corner to check for square. I f things are not, Find which direction and make note how much out of square.
Then you will have to adjust the car into square, by clamping one end and pulling the other to the correct position( with power off)and then power up while holding the car in square. when you power on the motors will lock in place. Then if you see your wheels are slightly off, run through the gusset adjustment routine again.
You should only have to go through this once. Its part of the assembly and set up process.
Good Luck

[walnutman]

Thanks for the tip Andre. Excuse my ignorance, but what exactly are you referring to when you say gussets. Is this lossening the large allen head screws that hold the large horizontal aluminum piece that will hold the z-assmebly?

[andre]

No not the black allen bolts. Under neath the al frame are 5/16 bolts that attach to the blue "gussets". They are the angled brackets that support the aluminum frame to the arms.
loosen those. I said the same thing when I got mine. "What the heck is a gusset?"

[weslambe]

Jeff,

Another great trick for squaring is to get a 90 or 60 degree vbit and put it in your router/spindle. Move to x1y1 and do a z2. This will give you a little working room. While at x0y0, move your z down to zero over your spoilboard and spin the bit with your finger as you ease down into the material just enough to make a mark. Now pick up your z to safe height and move up the y axis 30. MY30 Do the same thing with the bit. Make a mark. Move your bit (after safe z) to x40y0 and make a mark again.

What you have just done is a 3-4-5 test or the pythagorean theorem. Put some thumbtacks in the center of the marks and then measure the diagonal distance. It should be 50" If it's less then you need to move the far end of your gantry (the y49 side) to the left some. If it's more, move it to the right.

Less cutting involved with this test and it's nuts on accurate.

A gusset is any piece of material that is used to reinforce the joint where two disconnected parts meet. They are usually angled. Those decorative brackets under kitchen breakfast bars could be called gussets I guess.

Regards and good luck.

[walnutman]

Thanks again to all who posted here to help me out. It took me the entire day, but I think I finally got it all level and square with the bearings running fully seated accoss the entire rail. When i first read the comment in the manual "Congradulate yourself when you finish this step because it is the hardest" I kinda of thought why would it be so hard. Man, it truely was a PITA. I spent almost the entire day on it. I was able to get the Z assembly installed as well as the motors. The mosquitos drove me inside, so Im done for the night. Hopefully, i wont have the same headaches from here on out. I did notice the the x-car and z-car where both kind of stiff and took a moderate amount of force to move with the motors installed. Not a lot of force. But certainly a big diffence from when no motors were installed. What is normal? Can the pinion gears be too tight against the rails? Is the bearing adjustment for the z-car critical? I adjuested the bearings to be tight against the rail groves, requiring a bit of fource to move the car even without the motor isntalled. Is this correctly done?

[andre]

Hey Jeff
You want to make sure your motors are firm against the rack gears with no play whatsoever. you wheel guides should slip through your fingers with out stopping when moving. The stepper motors when turned off are supposed to be stiff and you dont want to move the car by hand with the power on or off. they produce static electricity that can short out the control box. You can move it slightly to align to square but do it slowly and only an inch if need be. I would double check all of your assembly make sure everything is tightend down and connected and start to practice

Good luck!

[jhicks]

Jeff, one simple trick to verify what you believe is true on level rails from corner to corner is...
Take a flexible wire cable or even some heavy fishing line. Loop one end over opposite corners to create an X. One string from 0/0 to 96/48 and another from 0/48 to 96/0 corners. Best with 2 people.
loop over one corner and hold taught over the opposite corner. Person #2 does the same thing on opposite corners.
NOW IF your rails / table is level, those strings/lines will intersect in the middle at the same height and just barely touch one another. If that looks good, reverse top and bottom strings so you can verify they are still JUST Barely touching at the intersecting cross over point.
IF yes, your corner to corner rails are flat. IF not, you can gently nudge up the threaded bolt feet to bring those strings in line until level.
This will assure you the table isnt "tweaked" with corners at slightly different heights. From there you can shim along the lengths and know all corners are true and level with each other.
We find this much more accurate than lazer but use both as sanity check and verification.

[weslambe]

Jeez Jerry, how am I going to be able to justify buying a transit now? My wife will never let me when she finds out a string will do the job.

Dang.

The KISS principle at work.

[walnutman]

LOL, I was hoping this would be the excuse for me to buy one. I have been wanting one for some other projects around the house, but could never justify the expense. Look like this will take some serious rationalising

[jhicks]

Well guys sorry to disappoint but keep in mind some of the Egyptians and Romans built some pretty sophisticated pyramids and aquaducts before we had lasers.It's not really my fault but if your wives dont get it, maybe they can be blocked from the forum??
:-)

[weslambe]

Hey Jeff, just ignore Jerry. Act like it never happened.

In all seriouslness, a good transit would really ensure that your machine was truely level. Like I said above, I was amazed at how far from level I was after being checked by a transit.

It still may be worth the extra cash. I have a 2 acre pond in my front yard and am looking to expand it and define the banks some. I guess I may have to justify it using the pond as my primary reason.

[jhicks]

Wes, don't tell her about the water/Tube level!
Jeff, do what works for you but don't look into that laser!
:-)
Above all don't blame me!!