[widgitmaster]

After the welder dropped of the Gantry ends & legs, I decided to play in the shop for an hour or two!

The two short-frame sections need to be cut to length (60") and have two 3/8" dowel pins and one 1/2-13 threaded hole per end. The spacing of all the holes & pins is critical, less the frame end up as a parallelogram :nono:

So I measured the tubes and found they were 1" too long, and decided the best way to accomplish this is to start in the middle and work outward!
Using a tape measure, I marked the middle of the tube, and drilled & reamed a 1/8" diam. hole at the center point. Next I moved over 24" which is about the max travel on my mill, and drilled & reamed another hole on either side of center.

Next, I placed a gauge pin in the hole and used an edge finder to pick up center of the pin while it was sticking out the side of the tube. Then I moved over 4 1/2" and set the DRO to zero. Now I drilled & tapped a 1/2-13 thread thru one wall. Then I moved over .875 and drilled & reamed the 3/8" dowel pin hole. When finished I pressed the dowel pins in, leaving them protrude about 5/16" Then I repeated the process on both ends of both tubes!

Lastly, I measured and scribed a line at the 30" mark (half the tube length) and band sawed the remaining bulk off!

[bill south]

Welcome Back Widgit!
Glad to see you back with all of your exceptional magic! Can't wait to see this monster in action!
Bill

[widgitmaster]

Got a late start today, only had enough time to setup the mill to mill the ends of the legs! Then I Drilled, tapped & reamed 4 of 6 legs!

[widgitmaster]

Welcome Back Widgit!
Glad to see you back with all of your exceptional magic! Can't wait to see this monster in action!
Bill

It's good to see your still lurking around the Zone Bill!

[widgitmaster]

I took a break yesterday, and this morning I started early and finished one of the longest tubes!
It was difficult to get it in the vises, and i had to open the garage door which let out all the cool air

With the tube in the vises, I used a tape measure to locate the approximate center. Then I inked up the tube and scribed a line. Using a point in the spindle, I set the DRO to x-zero on the line. Then I used an edge finder to center the y-axis in the middle of the tube.

According to plans, I can drill & ream five 1/8" diam holes a distance of 24" apart. This allows me to slide the tube over and dial the hole in and work on the next section. Its the most accurate method I can think of, for drilling & tapping so many holes in a 109" long tube!

After all the small M6x1 holes were drilled & tapped, I proceeded to drill the five 1" diam thru holes and give them a heavy countersink for welding!

That went well, and only took 5-hours!

The next tube is in the mill and ready for drilling, but not today!

[Jason Marsha]

Looking good widgitmaster.

In pic 9 did you start with that large drill bit or did you use smaller bits first working up to the large one?

Jason

[widgitmaster]

Looking good widgitmaster.

In pic 9 did you start with that large drill bit or did you use smaller bits first working up to the large one?

Jason

Hi Jason,
YES, I used a 3/8" drill as a pilot hole!
The location of the hole is not critical, as the 1" diam plug gets welded from both ends. Then they get drilled & c-bored for a 1/2" SHCS
Widgit

[harryn]

I am impressed that you were able to get a piece of square tube that looks that good. Most of the stuff around here only slightly resembles a square.

[widgitmaster]

I am impressed that you were able to get a piece of square tube that looks that good. Most of the stuff around here only slightly resembles a square.

Hi Harry!
Actually I bought two 24-foot tubes from the local steel supplier! All total, the steel was over $700 bucks



Today I finished up the 2nd long tube, then I placed one of the 25mm rails on it to see if all the holes line up! And I lucked out

Next I cleaned & organized the garage, as I have to wait till Sunday for the welder to pick up the next batch!

[lancut]

Hi Widgit, As retired tool & die guy I appreciate nice work when I see one. I like it! I also like the powerfeed on your mill knee. I wish I could do the same on my series I Bridgeport but it just not enough room for both the knee and the saddle (Y).. Will check on your progress periodically. Be safe.

[widgitmaster]

Hi Widgit, As retired tool & die guy I appreciate nice work when I see one. I like it! I also like the powerfeed on your mill knee. I wish I could do the same on my series I Bridgeport but it just not enough room for both the knee and the saddle (Y).. Will check on your progress periodically. Be safe.

Thanks!

Tomorrow I'm going to visit all the local Pawn shops to see if i can locate one willing to trade a 24" vernier height gauge (china) for a nice Milwaukee 14" abrasive chop saw! They are of equal value, and the height gauge is new!
I'll need it to cut the case hardened 25mm linear rails! I plan on facing the ends square, then drilling and reaming the ends of the rails so I can put a hard dowel between them! We don't want any bumps when the linear bearings roll over the seams!

[widgitmaster]

I was a little irritated this morning, the 2.2KW water cooled VFD spindle & controller arrived via Fed-EX around 8:30AM
The knuckle heads in California sent me a 2.2kw controller, and a 1.5kw spindle with ER11 collet!

So now I have a claim open in eBay against the seller!

[fuper]

Next I made the base plates for the gantry ends, this assembly will go to the welder!
After Drilling & c-boring all the holes, I added one more 3/8-16 hole so a long threaded rod could clamp the pieces together!
It's easier for me to maintain location and squareness!

Hello Widgitmaster,

May I ask what type of Mill you have? Also I don't see any layout lines [at least they don't show up in the picture] are you using a DRO to keep track of everything or are you doing it by counting off wheel turns?

Shane

[widgitmaster]

Hello Widgitmaster,

May I ask what type of Mill you have? Also I don't see any layout lines [at least they don't show up in the picture] are you using a DRO to keep track of everything or are you doing it by counting off wheel turns?

Shane

I bought the Bridgeport type knee mill new from KBC Tools, then I added the Mitutoyo KA Counter with 4-place decimal accuracy.

[widgitmaster]

Question,
Can anyone help me understand the Rack & Pinion & Servo motor configuration, so I can order all the right stuff !
I have been looking at the NEMA34 Servo at HomeShopCNC.com

It's the 850 oz/in servo.

Do I run it direct or with reduction pulleys & belts?
I have been looking at 1/2" x 1/2" 20-pitch rack gears & pinions, and do not know what pinion to get!
My expectations would be a rapid feed rate of 1000-1500 inches per minute!

There will be Rack & Pinion & Servo's on both the X,Y & A axis. The Z-Axis is linear slides and a 25mm Ball Screw with 10mm lead per revolution.

[CarveOne]

I can't help with the servo questions but I can certainly recommend getting your gear racks from Moore Gear. A lot of us here have their racks and others have gotten theirs through McMaster Carr. If you call Moore Gear ask for Dianne. She has been a good interface for us on CNC Zone. They are in Missouri. Their site has very good technical documentation about how to butt join the gear racks for long machines and other things of interest.

[Dylwad]

Definitely need reduction on all axes with those servos.

Have you looked into DMM tech A/C servos yet? Or the hybrid servos at keling? Might be options that would be easier to get going.

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[widgitmaster]

So far I have located the Racks at McMaster-Carr, and the reduction pinion & belt & pulley assembly at CNCRouterPartss.com

How do I know what ratios this will give me, and what the rapid feed rate will be? It would be nice to have a formula!

[widgitmaster]

As for the AC Servos, I don't see any advantage!
Geckodrive.com sells the most practical controller for servos I have seen so far, they hook up as easily as steppers to a breakout board and use a the same 80VDC Power supply!

[Dylwad]

As for the AC Servos, I don't see any advantage!
Geckodrive.com sells the most practical controller for servos I have seen so far, they hook up as easily as steppers to a breakout board and use a the same 80VDC Power supply!

A/C servos don't need as large of a reduction as brushed DC, which makes them easier to design for in the case of replacing steppers, in a way.. Depends on the setup.

Im all about geckos, never used anything else, but there are many other options now.

From cncrouterparts site

MACH Settings for R&P:The R&P system is based on a pinion with a 1" pitch circle. The total linear distance traveled per revolution of the pinion is thus 3.14159". With the Nema 34 R&P 2:1 reduction, this means that the distance traveled per motor revolution is 3.14159 / 2, or 1.5708". If you have a stepper with 200 steps per revolution, this means you have 200 / 1.5708" = 127.324 steps per inch, or 0.007854" per step. With 10x microstepping (like in the G201x or G203V), you would have 1273.2 steps per inch, or 0.0007854" per step.

Going by that, I would think brushed servos would need at least twice the gear ratio to the pinion vs steppers. Are you planning on running from a parallel port or using something inbetween to take the load off of the computer?

Remember the continuous torque is only 170 Oz in. On the homeshop nema 34 servos, but the max rpm is over 4000

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