PRT ShopBot upgrades

[pro70z28]

I've been procrastinating for long enough, I'm finally getting around to the upgrades on the old ShopBot. Out of necessity I've already upgraded the computer to a new windows 10 touch screen, although the touch screen part doesn't get used because the 'puter is in a box to keep it clean. Also replaced the control board with the latest version, as the old original died along with the 3PH Woods spindle control replaced with a HUANYANG VFD.

The dust collector boot is coming along, still have to drill & tap some holes. I cut the parts on the laser, split the boot so I could change bits without having to raise it high enough to get the boot off, magnetic attachment. It rained today so I played hooky today, working on the boot. So, tomorrow will be a work day. Unless it rains again.....;)

[pro70z28]

I miss calculated the clearance for the front magnet holding the boot. I didn't think the spindle would go high enough to hit the gantry, but it did by about 1/2" from the top of the travel. I cut the magnet tab off and relocated one on each side back far enough to clear. Everything fits now, snug but everything clears. I wanted to keep everything inside the gantry to keep it all out of the way. I have a few more parts to build for the vac system & then I can tear the CNC apart to start installing all the update stuff.

[EricSchimel]

That's a very cool mod. I'm into making dust shoes myself:

That one is 3D printed, and has some embedded rare earth magnets in it.

https://photos.app.goo.gl/JW7CWMZ9XuD3Rpds7

What did you use to design the yours, and how did you bond the acrylic together?

[pro70z28]

Thanks Eric. I designed this one with Flexisign. It's the program I use everyday in the sign bus., so I'm most at home using that program. I used ''SCI Grip'' acrylic glue to bond the parts.

[Brady Watson]

A few things if you're freshening up your PRT. First, the Z axis...those t-rails wear hard on only 4 v-roller bearings. The holes for the axles are already drilled in the Z for 4 more. Get some knock-off bearings from VXB etc, and the cam adjusters. It makes the t-rail surface last WAY longer and makes the Z stiffer...and they're cheap. If your t-rail is getting worn out, lay a weld bead along the length and regrind it. I know you have metalworking skills & probably have enough hand control to pull off a steady result. Belt sander works best.

You can gain another 1.5" of Z if you put the Z axis 90 deg brackets on TOP of the 1.5" utility strut. Not sure if you want more Z height, but I thought I'd mention it. You would have to drill four 1/2" holes for the bolts, but it's not hard.

And finally....Kudos for actually making your own dust foot. It always irked me that people who own their own CNC preferred to buy a dust foot rather than make their own. It's sad....but that's just my perspective.

[Chuck Keysor]

Brady, that is a great idea for getting 1.5" of added Z height. I'll do that after I finish installing the steel tubes on my X-car. (I finished fitting both of them today. Now I have to drill/tap and paint before welding...) Thanks, Chuck

[pro70z28]

Looks like my post didn't post.

I've never had a "Z" height issue in the past but maybe with the addition of the 4th axis, that might be something to consider. I did order a set of V bearings though. Thanks for the tip Brady.

[Chuck Keysor]

Hello Gary, I was looking at the VXB site, and saw lots of options for the V-bearings. What part number did you order? Thanks, Chuck

[Brady Watson]

The originals are Bishop Wisecarver #2 size. They have a 3/8" bore and are for use with 3/16" rail (like SB).

These knock offs are too cheap to resist @ under $12 for 4 of them. VXB V Groove Bearings (https://www.vxb.com/Set-of-4-RM2-2RS-3-8-V-Groove-Guide-Track-Sealed-p/rm2-2rs-4pcs.htm) FYI - genuine BWC ones are somewhere around $50 each.

Now the pricey bit are the eccentric bushings that allow you to adjust the tension between the rollers & T-rail. They need to be 3/8" OD and 1/4" ID - you'll use 1/4" bolts and nylok nuts to secure them to your Z axis.

Here's a set of 6 here on Ebay (https://www.ebay.com/itm/Adjustable-bushing-6-pack-for-2-V-groove-bearing-Stanless-steel-3-8-OD-x-1-4-ID-/142241045604?_trksid=p2385738.m4383.l4275.c10) - look around...I am sure there are other sources. If you find a better deal - post it to the group so others can benefit from your findings. You may want to get the 12 pack (also on Ebay) and split it among others on the board to save some bucks. You only need 4 - one per bearing.

...and of course, you can source the eccentrics from ShopBot. I don't know the price, but they will be OEM genuine BWC.

Happy tinkering people...

[pro70z28]

Eric, these are the ones I ordered. I just clicked on the firsts ones I saw.

https://www.amazon.com/gp/product/B01NARN23I/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1


Brady, I am a miser at times. I planned to make some eccentrics on the lathe. Chuck the stock up off center a tad, drill a hole, then re-chuck and turn to size. I planned to make the washer part of them large enough to put a couple flat spots on them so I can adjust them & Hold them while tightening the nut. Might work might not, but I'm always up for an adventure.

[Brady Watson]

Nice find on the Vrollers...even cheaper than the ones I posted when you factor in shipping, if you have Prime.

You might want to consider starting with some hex stock. I believe they take a 7/16" wrench, so: 360 Brass $9/ft (https://www.mcmaster.com/#8952k26/=1ecvaqo) It's way cheaper/easier than trying to put flats on round stock.

[pro70z28]

I'll probably end up using what I can find laying around the shop.

[Chuck Keysor]

Thanks Brady for the bearing and eccentric supplier information! I just got done ordering the bearings and eccentrics from the sources you provided.

If I may, since this isn't my thread,,,, when I get my 2 1/2" x 1 1/2" steel tubing welded on my X-car, would it help to weld some gussets or struts into the corners between the new tubing and the existing 3"x3" tubing?

Thanks again, Chuck

[Brady Watson]

Chuck,
The tubing you add will be butted up to the 3x3 ends of the gantry. It should be welded on all 4 edges. It is important to understand that welding is not gluing and it's not brazing or soldering either. Welding means that the both pieces to be joined together are melted to a semi liquid state under controlled conditions and filler material is dipped into the molten puddle whereas both pieces are fused together into one continuous piece or, welded together. So no, I don't think you need any gussets on the gantry itself. Put them on the frame if you don't already have them.

[Chuck Keysor]

Thanks Brady. My adjustable eccentric bushings and V rollers have shipped...……. Chuck

[pro70z28]

V Bearings came today. I went out to the shop, just to see what the job would entail. I obviously haven't paid enough attention to this part of the CNC for awhile. I noticed just how worn the t-rail is. I think I'll leave it as is until I get the other upgrades done, then tear it down and address the t-rail issue last. By then I'll have installed the 4th axis, so I'll have a better idea about Z clearance. Then I can tear it down once for both issues and be done. As bad as the t-rail surfaces look I'm surprised there isn't more play, hasn't been much noticable chatter. I haven't cut metal for a long time, I'm guessing it'd be noticable then. Since the V-bearings I bought come as an 8 pack, I'll probably just replace them all when the time comes. BTW, they look pretty well made for the price. Thanks for the heads up on the t-rail issue Brady.

[pro70z28]

Another thought I had. I have an old Multi Cam 4'x4' CNC that I retired, when an out of production Chip on the control board was fried by lightning. Fried the socket in the board too. It has an extruded T-slot table top, belt driven X stepper motors and a ball screw drive Y motor and screw Z motor. Could those stepper motors be used, they worked fine at retirement? Just wondering if a ShopBot control board would drive those motors? Is it just a matter of matching up a driver to the motor plate information on the stepper or is it more complicated than that? If I could drive those steppers with new electronics, I think I'd be inclined to leave the ShopBot alone and modify the Multi Cam as a dedicated 4th axis. Before the gears in my head get spinning too fast, I thought I better find out if it's even feasible. I didn't go the upgrade route with the Multi Cam at the time for a couple reasons. One, I really wanted a 4'x8' table and second, the people I talked to 15 or so years ago, made it sound like the bare chassis was about the only salvageable parts. Any thoughts?

[Gary Campbell]

In the "step & direction" world, and as long as the drives match up with the motors, you can put any motor drive combo on any control system and any control system on virtually any machine. Of course, there are a few caveats, like many of the controls using legacy parallel and USB connections are speed limited, so you cannot use many of the high resolution combos and expect speed from them.

[pro70z28]

Thanks Gary. I may have to pull the old CNC out and see what I have to work with before I get too far into working on the ShopBot. I bought 2 - 4'x8'x.75" sheets of plywood yesterday. I set them up with parts to make the base for the Jet vac & dust collector. What was left I set up brackets for the south wall of the shop to hold the coropast inventory. Leaning against the wall doesn't do much for keeping the sheets flat. These racks will take care of that and keep me a little more organized. I'll probably get the racks built first, then go back to the CNC upgrades.

[pro70z28]

I got the parts cut out for the CNC Vac platform and brackets for material racks for the shop, on the ShopBot today. I spent the day building the racks to get the shop a little more organized. Easier now to get at what I need, when I need it. By the time I finished the racks the ambition level had dropped below a functional level, so the CNC upgrade will have to wait 'til I get another gap in the schedule.

[Chuck Keysor]

Hello Brady and Gary. I have loosely attached my new V-roller bearings as shown in the attached picture. I used grade 5 bolts for the new V-roller bearings. The bolts in the original V-roller bearings are grade 8. (They didn't have grade 8 where I shopped, and I assumed grade 5 would be OK...…) Was that a correct guess????

I had small cold formed burs on my Z rails as shown. I did cover up my rack with duct tape to keep from getting filings stuck in my grease before I commenced filing....


Thanks, Chuck

http://www.talkshopbot.com/forum/attachment.php?attachmentid=32022&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=32023&stc=1

[Brady Watson]

Grade 5 is fine. Start adjusting using the original 4. Put the new 4 on loosest position, then carefully cam them in against the rail. Keep in mind cam clock positions should be about the same for all rollers in the same line. Also keep in mind that you can affect pinion lash adjusting the rollers on either side. Just take your time and be deliberate.

[Chuck Keysor]

Thanks Brady! My welder friend just got done welding my 2.5" x 1.5" steel tubing onto my X-car. He hurt his knee not long ago, so in order to weld the bottom joints, we had to take the car off and flip it on its side. So everything is really torn apart now. I'll post that on my earlier thread when I have pictures back from the developer (:confused:). Sorry Gary for butting into your thread,,,,, Chuck

[pro70z28]

Not a problem Chuck. Thanks for the Photos and explanation. That will be one of the projects I'll be dealing with, later on. Good information to have.
I ended up having to work the regular job most of today, so all I accomplished was assembling the platform for the vac & dust collector. I've gone about as far as I can building parts. I have a pending CNC job, but they're taking their time, so it may be time to tear into the ShopBot. Just watch, as soon as the CNC is down, they'll say they've made a decision.;)