Pictures of new PRTAlpha Construction

[sagreen83]

Ok, if you are interested, I am putting together a new PRTAlpha 48x96. I just received it tonight, and I am totally excited! As I am a stickler for recording the progress of projects, I am taking pictures as I go. If you are interested in seeing how each of the phases of Alpha construction visit my site at

http://www.stevie-ray.com/coppermine/thumbnails.php?album=24

As I go through the construction I will be putting new pictures up until it is complete. So far everything is going as planned... Knock on wood!

Scott...

[olecrafty]

Scott,
Thanks for the pics. The table looks great. I have a question about your leveling system. Are the bolts standard rounded head carrage bolts? Standard carrage bolts are soft. You might consider a grade 5 bolt instead. Please keep the pics comming. I would really like to see the progress. I am foaming at the mouth to upgrade my PRT, but I have to pay off the new spindles first.

Thanks
Kaiwa
olecrafty@charter.net (mailto:olecrafty@charter.net)

[fleinbach]

Scott,
Great pictures, It looks like you'll be up and running in a couple of days. I just finished some final tune up of my PrtAlpha 120 and I can tell you, you will be realy excited when you see it up and running. By the way a little off topic but what program did you use on your web site to display the photos?

Thanks

[sagreen83]

The software that I am using on the site is called coppermine. www.chezgreg.net/coppermine (http://www.chezgreg.net/coppermine)

[fleinbach]

Thanks

[sagreen83]

Just put a few more pictures up on the site of the work we got done yesterday. Actually I thought we would have a lot more done by this point. Getting that 2nd rail parallel is a nightmare!

http://www.stevie-ray.com/coppermine/thumbnails.php?album=24

[kerrazy]

Scott, Just one thing I noticed that has me gravley concerned......
Your SHop is WAY TOO CLEAN!!!!!!!

Dale

[bryan]

That because he been spend all his time putting together his new bot, Give him a week or two. and the dust will be there. ;-) Bryan

[paco]

I had the issue that 3 wheels where running good but a fourth was always off centered, this along the rails lenght... This meant, to me, that this wheels needed to be shimmed to get it centered... This shortened A LOT getting rails parallel... Where your C-channel flat at side along lenght? Installed flat to each other from table builder? My table legs are'nt as square as yours; to get my C-channel sides flat to each other...

Interesting color!

And it's sooo clean all around! 8-)

[dvanr]

Scott,

Looking through your pics , I noticed you have wooden shoes spec'd (You have dutch blood in you by any chance?)


The picture reminded me of this fellows design for a machine foot (http://www.industrialhobbies.com/howto/tips/hockeypuck.htm).

Lookin good Scott.

DvanR

[sagreen83]

Well... Finally got the rails all set up. And Paco you were right, I had to shim a wheel to get one of the tires to set down correctly. But... to make the process faster, I made a spacer to go across the rails, and bolted a dial indicator onto the end of the spacer. So to straiten the rails I did this...

1) Made spacer with dial indicator on the end.
2) Lay the spacer between the rails so that one end touched the 1st straitened X-rail, and the dial indicator touches the un-straitened rail. The spacer should be over the top of the center bolt on each rail.
3) Make sure the 2nd x-rail is loose, and run the car over the top of the spacer / dial indicator. Record the value on the dial indicator.
4) Move the car out of the way and push or pull the rail out until the dial indicator reads the recorded reading. You will probably have to compensate up to 20 1000ths due to flex after the bolt is tightened.
5) Repeat on both sides of the center bolt.

This process nailed parallel very quickly after I figured it out. If I would have known this, the straitening of the 2nd x-rail could have been done in an hour!

[paco]

One other "problem" you might encounter is that you can't test Alpha motors (Xs) having one unpluged; the control box will be ignoring any command... All motors should be connect to control box to... connect properly! I just disengage one X COMPLETLY to test.

[sagreen83]

Ok,

Finally got everything up and running. I've cut out a few text signs... Mostly I have been tweeking everything to get it all right. There are new pictures up on the web site at
http://www.stevie-ray.com/coppermine/thumbnails.php?album=24
There are 2 pages, so make sure you check out the 2nd page for the rest of the pictures.

A couple of things I have noticed / encountered.
1) The X racks on the X rails were bent / warped down their length to the outside of the rail. I didnt report this issue until I had the x-rails mounted on the table and straightened. I called Shopbot, and their recomendation was to replace the entire set of X-Rails, or if I felt I could do it, re-position the X-racks on the rails. But they said this would be pretty tough cause the tape holding them on is pretty strong. Well, they overnighted me some of the tape and we set out repositioning the x-racks. It was tough till I came up with the idea to heat the rack with a heat gun and pry it off with a putty knife. Worked like a champ. If you have to do this, definately do it after you have the rails mounted. This turned out to be a really easy thing to do with the heat gun.

2) The "Dial Indicator" idea above is the only way to go on aligning the 2nd rail!

3) As paco mentions above, I had to shim one of the X-wheels to get everything rolling correctly. This was after the rails were aligned to within 5 1000ths! I would have thought this would have been better, and that the X-wheels would have been aligned correctly when it left the dock.

4) I am having a problem where the router wont run using the SO command as mentioned on the extra sheet of paper that is shipped with the manual. However it will run if you flip the output 1 switch on the keyboard. Shopbot is aware of this issue.

5) I'm having a wierd issue with one of my contactors. When I power up the shopbot control box I get a 12E flashing on the main board. If I hit reset it doesnt go away. If I manually depress the center of the Top large contactor, it goes in, and after this I hit reset and the error message goes away. Shopbot is aware of this issue as well.

All in all, even though I was super frustrated in the beginning, this has been a pretty easy install. It took longer than I expected, but if I were to do it again, I could get the whole thing running in a day with what I know now.

Scott...

[slendon]

Hi Scott,

Thanks for all those photos, I'm one of the sixty or so who has been following your progress. I am anxiously awaiting the shipment of my alpha machine, and your photos are helpful. Have spent the last three weeks changing my workshop around to fit the bot in. My next job is to build the table, however the only C section steel that I can get for the X rails is 60mm wide,can anyone who has an alpha machine indicate if 60mm will cause interference problems?

Thanks
Steve

[sagreen83]

Steve,

If you have any problems during the install, send me an e-mail and I will give you my telephone #. Since it's pretty fresh in my mind, I could be able to help with the build.

Sorry cant help you with the alternate choice in steel.

[paco]

If you mean something around a 6" X 2 3/8", the only "problem" (not really) is that you will lose a big 3/4" in between your table sides... Table can be made from various material (maybe not plastic... or ice!!!)... You do need to keep distance respective to suggest plan...

[jlawren6]

Scott,

Thanks for posting the pics. I'm contemplating buying an alpha and your comments/suggestions are appreciated.

I wonder, however, if you might be willing to post some more photos? Specifically, I'm interested in seeing some closeups of the bearing arrangements on all 3 axes the pinion to rack interfaces. Just trying to get a better feel for how the machine is designed/built. With only a couple of pictures avaialable on the Shopbot site and no alpha user manual ready for download (at least that I can find), it's hard to really see what it's made of and how rigid it might be. Or maybe someone can point me to where I might find pictures along these lines. Thanks again.

Jon

[fleinbach]

Your C channel is 3/8" wider then the 2X6 in the instructions. As long as you maintain the interior clearance you will have no problem at all. The X car stops are fixed and can not be changed. (well at least not without a lot of modification)If you do not want the X car to run into the legs be sure to maintain the suggested interior width. I welded my table before recieving my machine and had no trouble aligning the X rails. But I did not drill the holes for the X rails until they where clamped down and roughly aligned. Then I marked the center using the X rail as a guide.

[paco]

I think that distance between table sides X rails holes are more critical than anything... Legs can be weld under table sides... (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=7&post=15724#POST15724) You'll also need to keep distance of thoses holes to exterior of table sides as suggest from SB plan to clear space for rack on X rails...

[sagreen83]

Jon,

Just posted a few more pictures of all of the bearings. In the 2nd X rail / Bearings picture you can see the rack and how its mounted. The rack is mounted by 2 allen head screws, and double sided tape. I wouldnt have thought the double sided tape would be a very strong arrangement until I tried to get one off! I mentioned a problem in an earlier post in this thread where I had to take off my X-racks. These things were held on very well.

The Y rails / Bearing combination work well. Basically you have a "V" shaped roller / bearing that rides down the top of a machined piece of Angle iron. It has 2 bearings / rollers at each position (Both sides of the angle iron). No way for this to jump the track.

The X rails are another story, and the jury is still out for me on these. The weight of the Z axis / carriage holds the V rollers in place on the rails. But, for some odd reason, my carriage jumped the track the other night for no reason that I can figure. When I put the rails on the table, one of the rails had a slight (and I mean slight) 3 inch long section where one of the rollers would ride maybe 1/64" to 1/32" of an inch up on the rail. This was between the bolts, so there was no way that I could figure to fix this. The shopbot installer informed me that this wasnt an issue at all, and that the weight of the table would hold everything in place. And if you watch the carriage roll down the table with everything hooked up, there are no gaps anywhere. But mine still jumped off of the X-rails.

These machined areas of the rails can very quickly gather rust. Mine had a thin layer of rust down the entire length of the X rails after just a couple of days after install. I took steel wool and removed it. After which I applied a layer of "Slipit" (A rust preventative that I use on the tops of my table saw) and its alot smother now. I wonder if rust can play a factor in the carriages jumping the rails?

Also, another note on installing the Support / Spoil boards... I centered the Support board on my steel table as advised. This was a 49" x 97" piece of MDF. The problem is when you do center within the X-axis of the table you loose some travel at the far end of the X axis. Your X zero position is about 6 inches from the stop. At the X 96" position, you are about 1 inch from the mechanical stop. This is because the router bit is not centered between the Y rails. I would recommend offsetting from center, in the X axis at the X zero end, at least 2 - 3 inches. So basically you hang the support board off the X zero end 2 - 3 more inches than the X 96" end. Due to this, I will probably have to rebuild the support / spoil boards. This may have been in the manual, but I didnt see it if it was.


Hope this all helps!
Scott...

[jlawren6]

Scott,

Thanks for posting those and for the additional comments. They were exactly what I was looking for and they help quite a bit.

I had wondered about the possibility of the carriage jumping the X rails with only the carriage weight and the pinion load holding it down. I did not know if the X rail bearing arrangment had been changed with the Alpha to be more similiar in design to what is now used on the Y rails. That does not appear to be the case. Maybe it's not that big of deal, but your's is the second post I've seen recently about the carriage jumping the rails (first one was related to the dust skirt being too low I think). I thought Shopbot might have added some additional bearings in that area to either stiffen it in the Z direction or just act as a safety to prevent the carriage from leaving the rails. I hope it doesn't happen to you again. I can't see light rust playing a role, but at least you've eliminated the possiblity now. Also, thanks for the tip on the spoilboard.

I appreciate the help.

Jon

[fleinbach]

I'm not sure where along the X axis you derailed but here is one possibility if it was near the ends.

There was an issue with my X rails that may be your problem. Both of my X rails where bowed out on both ends between the first and second bolt hole. This can be verified if you have a good eye by siteing down the rail and confirmed with at least a 3 foot stright edge. I fixed this by drilling a 5/16 hole directly between and very close to the inside edge of the existing bolt holes. While tightening down on this bolt you can site down the rail and watch it straighten out or just use your straight edge.

As for the spoil board issue I have the same problem. It's realy not a problem but the reasult of making the Y car capable of carrying either one or two Z motors and having both capable of reaching both ends of the table.

[slendon]

Thanks for info folks,

Shopbot have also mailed me the July2004 version of plans for an Alpha table, which includes options for working round the x rail size query.

Off to the steel yard now.....

Steve