(231,’2006-07-21 12:00:00′,’figNoggle’,’2006-12-20 08:05:09′,’david’,’Project CNC 8×12 Lathe – The Master Plan’,”,’Well, this actually had been brewing in our minds since we first had the lathe…

With some free time on our hands, we spec’d out how this will work:

1. “DRO quills” (aka “DRO scales”) installed for the X and Z axes. (We thought of also adding a swappable DRO for the compound slide and tailstock, but in reality, our drilling needs rarely need a high degree accuracy since they’re mostly through holes and as for the compound… we rarely have any need for tapers. So, we’ll start simple.)

2. DRO display. Time’s a premium at this “little machine shop” and boy do we mean “little”. While the Shumatech DRO was also top in our list of things to do, taking the time to build one right now is something we can’t quite do. So, off we go to Shars (Remember, their eBay specials are always cheaper than their catalog pricing so it pays to check them out within eBay first. Their name is “discount_machine”.) The first unit was a “Positron-3A” that places such as Lathemaster and LittleMachineShop sell. This one has LEDs which makes reading easy. Shars unfortunately only has the LCD version with those tacky yellow buttons.

3. The motors. Being price-conscious, we’re opting to go with step motors again. The difference being that it’ll be of the NEMA 34 variety with loads more of POWER! We’re currently looking at KelingInc which is a Chinese manufacturer of motors (and drives too!) as well as other things.

Here are the choices. They all have a spec’d 637 oz-in rating for $89 (not bad). They go up to 1812 oz.in. but that’s definitely overkill. The X2 NEMA 23 motors are rated at 269 oz.in. and work well in direct drive (1:1) on the X axis, so to be on the safe side, an increase of over 100% should do it.

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in, ?” shaft with a flat, 80 mm KL34H80-45-4A (Single Shaft)

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in, 1/2″ shaft with a flat, 80 mm KL34H80-45-8A (Single Shaft)

KL34H80-45-8B (Dual Shaft)

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in,1/2? shaft with a flat, 80 mm KL34H80-55-4A

4. The drives. We really like the Xylotex kit, but wanted to try something different for kicks. Everyone talks about Gecko drives. OK, we’ll give them a whirl. BTW, the step motor line of their drives has only two differences between models; some have half and full stepping and some have short-circuit protection. Here’s a chart we whipped up while trying to decipher their product lines’ specs (wish they’d had a product matrix):

[MODEL #] – [MOTOR TYPE] – [7A, 80VDC] – [10-MICROSTEP] – [5-MICROSTEP] – [HALF-STEP] – [FULL-STEP] – [OPTO-ISOLATED STEP/DIR] – [SHORT-CIRCUIT PROTECTION] – [SILENT 20KHZ PWM SWITCHING] – [MID-BAND RESONANCE DAMPENING] – [NO LOW-SPEED VIBRATION] – [SINGLE UNIT PRICING]

[201] – [STEP] – [X] – [X] – [N/A] – [N/A] – [N/A] – [X] – [N/A] – [X] – [X] – [X] – [$114]

[202] – [STEP] – [X] – [X] – [N/A] – [N/A] – [N/A] – [X] – [X] – [X] – [X] – [X] – [$134]

[210] – [STEP] – [X] – [X] – [X] – [X] – [X] – [X] – [N/A] – [X] – [X] – [X] – [$148]

[212] – [STEP] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [$168]

Basically, their 212 has everything.

5. Break-out board. In our CNC X2 mini-mill conversion, we didn’t use home or limit switches. We just paid attention to our G-Code (and yes, it still went beyond our machine travel at times!) and used software limits. This time around, with a huge mass spinning in excess of 600 RPM it might be a good idea to watch where we’re moving the carriage! We haven’t isolated a vendor yet, but it may be Campbell Designs’ breakout board made by Sound Logic or back to Gecko with their “G-Rex” G-100 or G101. Difference between the two Gecko models? The G100 has an enclosure and lights and other widgets. The G101 is “just” a board.

6. Accuracy. There’s backlash! We’ll need to address this especially in the cross slide. The carriage will be driven by ballscrew directly mounted to the carriage itself, so this accuracy will be dependent on the screw/nut combo. The cross slide has its own anti-backlash nut (really, a split nut), but we may throw this all out in favor of a better ACME leadscrew and adjustable brass nut.

That’s the plan!

Lathe operations are quite repetitive. To us it makes great sense to automate much of the mass material removal and in cases where precision is critical, we’ll let CNC take us just shy of required dimensions and then take it from there by hand.

First, let’s buy some parts and install a DRO for those manual operations.

Of course the motors and drivers are important too!

‘,’

Well, this actually had been brewing in our minds since we first had the lathe…

With some free time on our hands, we spec’d out how this will work:

1. “DRO quills” (aka “DRO scales”) installed for the X and Z axes. (We thought of also adding a swappable DRO for the compound slide and tailstock, but in reality, our drilling needs rarely need a high degree accuracy since they’re mostly through holes and as for the compound… we rarely have any need for tapers. So, we’ll start simple.)

2. DRO display. Time’s a premium at this “little machine shop” and boy do we mean “little”. While the Shumatech DRO was also top in our list of things to do, taking the time to build one right now is something we can’t quite do. So, off we go to Shars (Remember, their eBay specials are always cheaper than their catalog pricing so it pays to check them out within eBay first. Their name is “discount_machine”.) The first unit was a “Positron-3A” that places such as Lathemaster and LittleMachineShop sell. This one has LEDs which makes reading easy. Shars unfortunately only has the LCD version with those tacky yellow buttons.

3. The motors. Being price-conscious, we’re opting to go with step motors again. The difference being that it’ll be of the NEMA 34 variety with loads more of POWER! We’re currently looking at KelingInc which is a Chinese manufacturer of motors (and drives too!) as well as other things.

Here are the choices. They all have a spec’d 637 oz-in rating for $89 (not bad). They go up to 1812 oz.in. but that’s definitely overkill. The X2 NEMA 23 motors are rated at 269 oz.in. and work well in direct drive (1:1) on the X axis, so to be on the safe side, an increase of over 100% should do it.

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in, ?” shaft with a flat, 80 mm KL34H80-45-4A (Single Shaft)

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in, 1/2” shaft with a flat, 80 mm KL34H80-45-8A (Single Shaft)

KL34H80-45-8B (Dual Shaft)

-NEMA 34 HIGH TORQUE STEPPER MOTOR 637 oz-in,1/2? shaft with a flat, 80 mm KL34H80-55-4A

4. The drives. We really like the Xylotex kit, but wanted to try something different for kicks. Everyone talks about Gecko drives. OK, we’ll give them a whirl. BTW, the step motor line of their drives has only two differences between models; some have half and full stepping and some have short-circuit protection. Here’s a chart we whipped up while trying to decipher their product lines’ specs (wish they’d had a product matrix):

[MODEL #] – [MOTOR TYPE] – [7A, 80VDC] – [10-MICROSTEP] – [5-MICROSTEP] – [HALF-STEP] – [FULL-STEP] – [OPTO-ISOLATED STEP/DIR] – [SHORT-CIRCUIT PROTECTION] – [SILENT 20KHZ PWM SWITCHING] – [MID-BAND RESONANCE DAMPENING] – [NO LOW-SPEED VIBRATION] – [SINGLE UNIT PRICING]

[201] – [STEP] – [X] – [X] – [N/A] – [N/A] – [N/A] – [X] – [N/A] – [X] – [X] – [X] – [$114]

[202] – [STEP] – [X] – [X] – [N/A] – [N/A] – [N/A] – [X] – [X] – [X] – [X] – [X] – [$134]

[210] – [STEP] – [X] – [X] – [X] – [X] – [X] – [X] – [N/A] – [X] – [X] – [X] – [$148]

[212] – [STEP] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [X] – [$168]

Basically, their 212 has everything.

5. Break-out board. In our CNC X2 mini-mill conversion, we didn’t use home or limit switches. We just paid attention to our G-Code (and yes, it still went beyond our machine travel at times!) and used software limits. This time around, with a huge mass spinning in excess of 600 RPM it might be a good idea to watch where we’re moving the carriage! We haven’t isolated a vendor yet, but it may be Campbell Designs’ breakout board made by Sound Logic or back to Gecko with their “G-Rex” G-100 or G101. Difference between the two Gecko models? The G100 has an enclosure and lights and other widgets. The G101 is “just” a board.

6. Accuracy. There’s backlash! We’ll need to address this especially in the cross slide. The carriage will be driven by ballscrew directly mounted to the carriage itself, so this accuracy will be dependent on the screw/nut combo. The cross slide has its own anti-backlash nut (really, a split nut), but we may throw this all out in favor of a better ACME leadscrew and adjustable brass nut.

That’s the plan!

Lathe operations are quite repetitive. To us it makes great sense to automate much of the mass material removal and in cases where precision is critical, we’ll let CNC take us just shy of required dimensions and then take it from there by hand.

First, let’s buy some parts and install a DRO for those manual operations.

Of course the motors and drivers are important too!

‘,”,”,”,’8x128x14-Small-Lathe’,”,0,”,0,4,1,1,’article’,”,”,’project-cnc-8×12-lathe-the-master-plan’,”,”,”,”,”,”,”,”,”,”,’869ac92e74f0b4db035b8afcad2c8609′,’2006-07-21′);