Alpha upgrade issues?

[stargategfx]

I've just packed it in for the day, a day spent mostly on upgrading my year old PRT to Alpha.
The mechanical part of the job is done, tomorrow I will attack the electrical end.
I am curious as to how others got through the upgrade process.
Things I noted:
The dimensions for the Z mount drawing are whack;
no hole sizes are indicated on the provided drawing and the placement of the hole (size determined after calling SB) is out by at least a quarter of an inch.
That doesn't sound like much but it sure feels like it when you have to mount and remove the Z motor a dozen times to test fit; and just try doing it with a Colombo spindle attatched.
The "stiffener" brackets were missing a part shown in the assembly manual, a square spacer plate, I hope it works without it.
They suggest that the Y gantry can be drilled to accept the stiffeners by moving the gantry to the very end of the x rail and the drilling from underneath thereby not having to disassemble the Bot....THROUGH TWO LAYERS OF WELDED 3/16" STEEL ON FOUR CORNERS???
They also suggest that these holes be drilled in the rails (if you follow the manual) after you run the new cables indide the rails WTF???
I am probably being overly critical, as most of us here are mechanically inclined enough to work around little problems like these, and I must admit that the crew at SB generally does an outstanding job but at this point I'm not looking forward to tomorrow.
If you've been down this road I'd love to hear your thoughts.

[ted]

Hi Boyd,

Sorry for the confusion on the Z holes. We'll take a look and see if we can straighten out the drawing. We had 3 different Z layouts that we were trying to adapt it to ... and may have just left a little too much to ShopBotter's inventiveness.

Now on drilling those holes in the X cars for the stiffeners ... We should probably have suggested starting with a smaller pilot hole and some sharp bits. This makes the thing pretty easy at least to the extent that I have managed it myself on 2 cars, and with battery powered drills.

Hope you enjoy the new PRTalpha speeds and performance. Start slow ... and work up to the higer speeds for cutting and jogging after you get used to movement ...

Ted

[bjenkins]

I'm in the process of upgrading a one year old PRT96 to an alpha as well. Boyd's observations are good ones. The Z axis hole was definitely a major hassle. Everything else went pretty smoothly. I was very precise in placing the hole in the z-slide assembly only to find that the motor could not be mounted. I ended up having to dremel an elongation to get close. The shaft of the motor actually was hitting the large hole it should be passing through.

I have another question about the mechanical stiffness of my upgrade. Are the brackets really enough to get the stiffness in the Xcar? It seems like the ramps possible would require much better structure. I was actually surprised at the limited hardware that came with the upgrade-- especially because I've seen the alpha and the extrusions that were added.

[ted]

Hi Bud,

You'll be surprised. The stiffeners add quite a bit. But, the really important thing is to add diagonal stiffness to the table. The gussets that we created for the new tools will not fit the old table, but this is a pretty straightforward improvement to make. Use some steel strut as diagonals, or just bolting on a 1/4 sheet of plywood will actually work well too. There is much more lateral flex potential in the table than the car. And because the flex will cause the table (in end view) to move like a parallelogram, this motion can actually displace the cutter.

You will also be surprised/impressed with how smooth the acceleration and deceleration is with the new motors.

-Ted

[williamim]

Hi Boyd & Bud

I had the same problem with my Z when I upgraded my PRT last month. I now also have an elongated hole in my Z. It seams to be working fine at this time. I notified ShopBot of the problem and I was told they will make the corrections.

[stargategfx]

I just put the "pedal to the metal" on the Alpha for the first time today....
HOLY SMOKES, what an improvement!
Faster, much faster, quieter, smoother, more accurate, did I mention faster?
After a couple of frustrating days with assembly and electrical issues we are finally back up and running again.
The wait was well worth the result, I am very impressed.

[wayneo]

Hi Everyone......
I also have been upgrading my PRT-96 to an Alpha. Everything seemed to go just fine to the point of working on the Z motor. Bad scoop in the instructions, drawing dimensions and so on. Of course I very carefully measured, re-measured (measure twice, cut once...) then drilled the stated holes. Then tried to fit the motor into said holes. Wrong! Hole placement was way off! Plus instructions state to place washers under the motor (between motor and Z-frame). And thus using only 2 bolts to secure the motor.

Well, this "hole" thing seemed too rube-goldberg to me. You remember Rube....Eh? So I very carefully measured the dimensions on the motor. Found the sholder thingy on the motor to be problematic and would not let the motor seat flush against the Z-Frame (as the oblong hole in the Z-Frame was too small). So, made a trip to Alaska Industrial and got a new carbide die grinder bit for my air grinder. Marked out exactly where the large hole should be enlarged to and started grinding. It took a full evening of grinding to get the job done.

Now I positioned the motor firmly against the rack gear (and pinion gear) and used centering punches to locate the holes needed for all 4 holes on the motor flange. Drilled out these holes, and found that 2 of the holes is where a square tube member was welded exactly in line with the holes.

So, using my handy air grinder, I was able to remove enough material from the square tube so that i could tap threads in the Z-Frame. The other 2 holes were hard to get nuts on the back side, but using real long needle nose pliers I was able to get them started, then used a long wrench to securely tighten. I used nylock nuts so that vibration would not cause them to loosen.

I now have a very secure and ridged Alpha Z-Motor fastened to my Z-Frame. Perhaps I did a little overkill, but I doubt that it will ever come loose or rack out of position.

I guess I was a little disapointed that this part did not go a little more smoothly. In my humble opinion, only securing the Z-Motor with 2 bolts (with washer spacers between the motor flange and the Z-Frame) is a little short of what I expected from ShopBot considering the price I paid for the Upgrade.

Also, I was surprized that the new vacuum foot assembly was not included as was the angle bracing for the table. The reason that I say this is that I enquired specifically asking "So, when I purchase and install this upgrade.... it will be exactly like an Alpha machine?" I was told, "Yes, it will be exactly like an Alpha machine."

I hope I am not being too picky, but I really did not expect to have this much hassle completing the upgrade, and expected the results would be as I was told before the purchase.........


But, moving on, I am sure this will be a nice machine once it is completed..... Just thought you might like to know my experiences......


Wayneo

[bjenkins]

I have a couple suggestion for others who upgrade. BTW, Ted and gang, these would be easy additons to the package.

I made a template from a small piece of cold roll steel to drill the new holes for the motors on X and Y. A paper template could be sent with the instructions. The template made it easy to position the holes and drill them accurately. The Z axis is where it would really pay off. It would also help to make it more clear how to orient the motor on the slide.

The biggest thing you don't get that is critical is the gussets for the table. If you have an old style steel table, you can make a very functional version by laminating two pieces of 19mm plywood (I did that for our international pals-- 3/4" for most). The two lapped piece form a single gusset that has a coplanar surface to bolt to the leg and the horizontal.


3267 I've never done an image on the forum... This is a quick and dirty example of the idea, but one of the short lines is actually a hidden line.

[fleinbach]

Wayne

Sorry to here about all your problems with your Alpha upgrade but I would like to comment on the statement you made about the 2 bolts on the Z-motor. I believe this was a good idea and reduce's strain on the rack and pinion gear. If you notice you can slightly flex the motor left to right. It works like the spring on the X and Y car motors. If you where to add bolts in the 2 other holes you might put too much strain on the rack and pinion gear thereby risking more wear or possible damage.

[grant]

To the gentlemen that have had trouble with their Z axes -

I was working with someone today that called to report the same issue. I collected what information I could and then set out to resolve the situation. Armed with the drawing provided with upgrades, I went and talked to Zac, who builds the majority of our Z axes. I told him about the problem we were having in the field. In response, he took a used PRT Z axis frame off the shelf, marked it using the measurements in the drawing provided, drilled a hole and mounted the motor. It was perfect. At that point he told me that he did 60-70 conversions like this when we were going through the changeover to alpha machines. The only thing I can conclude is that we have moved the holes in the Z enough times over the years that the documents are not going to be spot on for everybody. Here's our best advice:

1) Take the router off of the T-frame. This will let you manipulate the Z axis assembly without it being in the way.

2) Look before you drill! If you mark your hole location and have the T-frame in place, you can check the alignment and mesh of the gear and rack before you decide to make your hole.

3) Reverse engineer. If it looks like the dimensions provided for hole placement are inaccurate, put a bolt through the motor and one of the mount slots that is near to the rack. Put the bolt through the approximate center of the slot, then rotate the motor until the gear meshes into the rack. Hold it in position and mark through the opposite corner of the motor. Swing the motor out of the way, drill your hole slightly oversize, and then put a bolt through it. If you had the first bolt in the middle of the slot then you should have some adjustment if you find there is backlash.

4) For those of you that prefer to secure the motor with three or four bolts, feel free to drill or mark through the holes once the motor is in position. You can avoid a difficult situation like Wayne had by drilling these holes true to size and tapping them out for the bolt.

Wayne - you should have gotten a dust collection skirt with your upgrade. I will see to it that one is shipped to you.

Best regards,

Grant Bailey

[wayneo]

SHOPBOT SUPPORT PULLS THROUGH!

On Monday I received a call from Grant looking for my address where he could get a Dust Collector sent to me.

Needless to say, I am impressed not only by the fact that SB Support cares about their customers, but that the read through the forum as well. Great concept! Problem caught and corrected before it got out-of-line..... More companies should take note!

Shop Bot and Grant get an A+ in my book! Keep up the GREAT work! Your extra efforts are being noticed!

Wayneo

[kilian55@comcast.net]

HI all I need help with my upgrade. I am working on my Zaxes and the motor will not fit flat on the plate that it mounts to. Did any one have to cut out the plate so the motor will fit on ?The new motor has a lip ,thats why it woundn't fit? Thanks for any help.

[larryk (Unregistered Guest)]

looks like super bot coming called on liner guides
will so pics>

[larryk (Unregistered Guest)]

hope it works. any help?
I am sick my neck out!

[larryk (Unregistered Guest)]

Thanks, for all the email. U are alot of help.