After 3 years, my first project is up and going.

[HereinCS]

I've been browsing and trying to learn from everyone here for about 3 years. Finally, I'm getting started. My goal is a 3 axis, very precise machine that will cut mainly wood, but occasional aluminum as well. I'm borrowing lots of ideas from everyone else's builds, but I won't pretend to know what I'm doing. It's going to be slow progress as I get the parts in. I do have a machinist friend who hopefully can help me with some parts. I'd truly appreciate some, any, advice. Please also let me know if I'm about to make a big mistake.

My design goal is to have a machine that has a work area of 4 feet by 2 feet. Precision is important so I went with the nicest sets of slides that I can afford.

Items in hand:
1. THK ball screw with a thread length of 44", travels around 42" with a .2 pitch. I bought this several years back, it's go a bit of tarnish, but looks close to new. Not quite 4 feet, but close enough.
2. I have 2 sets of THK SR25 rails that I'll cut to length. They are used, but are in good shape once I polish of the tarnish.
3. I have these two slides coming from ebay:
http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_6875wt_911 for the y axis
http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_6875wt_911 for the x axis.
Anyone have any thoughts on these?
4. I have a Bosch motor mount from K2.

Once I have the Parker Daedals in, I'll be working on the frame.

Thanks ahead for the comments and advices.

[CarveOne]

On a moving gantry design the space that the gantry occupies in the X axis (long axis) will limit your 42" travel to something less than that. Similarly, the space that the Z axis assembly occupies in the Y axis (shorter axis) will reduce the actual travel in that direction.

Your 42" travel can become closer to 36" in in actual practice.

CarveOne

[awerby]

instead of X axis? We made a router out of similar actuators; it works pretty well. We made a frame out of heavy steel tube to support ours; what's your plan?

One thing you might have to deal with is the weight of your router causing the Z axis to drop when power is cut. We tried using constant-force springs to counteract that, but they don't last long; gas struts are probably a better bet. The actuators are good at keeping dust out of the ballscrews and slides; are you going to make a bellows for the X axis?

If those are stepper motors on the ebay actuators, then it won't be hard to drive them; if they are servos then you need to figure out what sort they are. Some are easy to deal with, others are nearly impossible...

Andrew Werby
www.computersculpture.com

[Phife]

Carve one is right, I have a 4ft x 2 ft machine, my X screws are 62" long due to the size of the gantry and motor mounts/coupling. My Y screw is around 32"

Also what are you going to use the parker daedal for?

[CarveOne]

Originally Posted by awerby instead of X axis? We made a router out of similar actuators; it works pretty well. We made a frame out of heavy steel tube to support ours; what's your plan? One thing you might have to deal with is the weight of your router causing the Z axis to drop when power is cut. We tried using constant-force springs to counteract that, but they don't last long; gas struts are probably a better bet. The actuators are good at keeping dust out of the ballscrews and slides; are you going to make a bellows for the X axis? If those are stepper motors on the ebay actuators, then it won't be hard to drive them; if they are servos then you need to figure out what sort they are. Some are easy to deal with, others are nearly impossible... Andrew Werby www.computersculpture.com

The width of the Z axis assembly must be deducted from the total Y axis lead screw travel. At some point the Z axis body will bump against something or it will hit a limit switch.

Limit switch actuating points will need to be considered in calculating the total travels also.

You can start with the actual travel that you must have and add to it to arrive at the lead screw length that is needed, or you can start with the lead screw length that you have on hand and calculate the travel that you will end up with. These are the two main concepts.

You can design a narrow Z axis assembly, and a narrow carriage for the gantry to minimize the loss of travel with the lead screws that you already have. Try not to add anything else that will restrict the total travel in any way.

CarveOne

[HereinCS]

Originally Posted by CarveOne On a moving gantry design the space that the gantry occupies in the X axis (long axis) will limit your 42" travel to something less than that. Similarly, the space that the Z axis assembly occupies in the Y axis (shorter axis) will reduce the actual travel in that direction. Your 42" travel can become closer to 36" in in actual practice. CarveOne

I'm still looking for a longer screw. I actually have two very long screws, around 5 feet in travel, but they are simply too big for my practical purposes. I think they are around 1.75" in width. I invested a bundle, but now I'm thinking about giving them away. If anyone in Colorado Springs wants them, I have the screw, nut, mounting block. I'm not going to ship them.

The Daedals are meant to work together. The shorter one obviously mounts onto the longer one and the width is less than that of the trucks. I should be able to get 20" of cut, don't you think? I have not paid for them yet, so please advise.

[Phife]

Originally Posted by HereinCS I'm still looking for a longer screw. I actually have two very long screws, around 5 feet in travel, but they are simply too big for my practical purposes. I think they are around 1.75" in width. I invested a bundle, but now I'm thinking about giving them away. If anyone in Colorado Springs wants them, I have the screw, nut, mounting block. I'm not going to ship them. The Daedals are meant to work together. The shorter one obviously mounts onto the longer one and the width is less than that of the trucks. I should be able to get 20" of cut, don't you think? I have not paid for them yet, so please advise.

They seem pretty pricey, after shipping and all, you would probably make something custom. I dont see how they bolt together, you will probably have to make a plate to mate them together, and you will want to attach the longer one to some sort of solid metal backing. It wont be strong enough on its own to resist the flex.

[HereinCS]

Originally Posted by awerby instead of X axis? We made a router out of similar actuators; it works pretty well. We made a frame out of heavy steel tube to support ours; what's your plan? One thing you might have to deal with is the weight of your router causing the Z axis to drop when power is cut. We tried using constant-force springs to counteract that, but they don't last long; gas struts are probably a better bet. The actuators are good at keeping dust out of the ballscrews and slides; are you going to make a bellows for the X axis? If those are stepper motors on the ebay actuators, then it won't be hard to drive them; if they are servos then you need to figure out what sort they are. Some are easy to deal with, others are nearly impossible... Andrew Werby www.computersculpture.com

I did mean the z axis. So the z axis will slide down when there is no power? I have a set of Thompson rails, very similar, with brakes on them, but they are too heavy. I like the Daedals b/c they are pretty much self contained, and are very light for what they are. My Thompson set up must weigh 25 lbs without the router, the Daedal about 1/2 of that. That will allow me to build a narrower support for the gantry, perhaps to save another 2.5" by only using one truck on each x axis rail. I really like the screw that I have now for the x axis. Zero slop, nicely made.

An alternative, is to buy a set of x screws from LM2008 and do two screws on the x axis. But I want this machine real tight, and I'm not sure if Chai's screws are of that quality.

[HereinCS]

Originally Posted by Phife They seem pretty pricey, after shipping and all, you would probably make something custom. I dont see how they bolt together, you will probably have to make a plate to mate them together, and you will want to attach the longer one to some sort of solid metal backing. It wont be strong enough on its own to resist the flex.

I looked at the Daedal catalog, seems like the holes are meant to line up. Probably not a big deal to fab a mounting plate if they don't. I'll like mount them to an aluminum plate. I'm most concern about the y axis travel. I hope that it is indeed close to 20", since I can't use it if it's much less than that. One of the reason I like the Daedal is that I'm saving on the motor, motor mount, coupling, limit switch. Custom fabrication here in Colorado Springs can be difficult to attain, and expensive. Even with the help of a machinist friend (I'm still paying him). In the end, I think I'll come out ahead vs custom fab, and don't have to worry about alignments, etc.

[HereinCS]

Got my 203v. I hope they are as tough as their claim, I'm surely going to be the first to blow them up .

I plan to use them with this board

http://www.cnc4pc.com/Store/osc/prod...products_id=46

this jogger

http://www.cnc4pc.com/Store/osc/prod...roducts_id=162

this power supply

http://kelinginc.net/KL_6515.pdf

If I'm sounding like an idiot with the mechanical parts, I'm retarded when it comes to the electronic parts. I have another friend who is handier (and hopefully be bribed with the tons of excess rails that I've collected) who'll hopefully keep me from burning down our house.

Are my choices reasonable? Do I need anything else? I saw on candcnc.com that they connect the driver to some sort of serial plug so that I can just plug the motor in without having to wire it to the geckos. How did they do this. And is their break out board any better?

[CarveOne]

The choices look good to me. I'm using four G203V (dual X axis motors), C11G, Keling 72vdc 20A PS, and four Keling 495 oz steppers. Works really nice together.

The 72vdc PS is the max safe voltage option for the G203V. 65v is used by a lot of folks and the only tradeoff is a little less motor speed and torque.

CarveOne

[Phife]

Originally Posted by HereinCS Got my 203v. I hope they are as tough as their claim, I'm surely going to be the first to blow them up . I plan to use them with this board http://www.cnc4pc.com/Store/osc/prod...products_id=46 this jogger http://www.cnc4pc.com/Store/osc/prod...roducts_id=162 this power supply http://kelinginc.net/KL_6515.pdf If I'm sounding like an idiot with the mechanical parts, I'm retarded when it comes to the electronic parts. I have another friend who is handier (and hopefully be bribed with the tons of excess rails that I've collected) who'll hopefully keep me from burning down our house. Are my choices reasonable? Do I need anything else? I saw on candcnc.com that they connect the driver to some sort of serial plug so that I can just plug the motor in without having to wire it to the geckos. How did they do this. And is their break out board any better?

I use the same BOB and Power supply on my machine. Both work great, I have servos though so I use the G320s.

I'd skip the expensive MPG, not needed. I would go for a wireless xbox controller or shuttle pro controller, or something alot less expensive, that has more features than just jogging. Also you need to use another Parallel port for it. so more cost again.