Rockcliff Router Build

[rockcliff]

Hi
our plans do not include a design for a screw thrust, bearing,and yes some stepper motors, like low cost ones in dot matrix printers will have some end play, the router you plan to build, and your need to cut aluminum, end play will be an issue, using a thrust bearing on the screw is always helpful, to remove any load from the motor and stop it at the screw, our router design is very simple and would allow for thrust bearings to be added if needed, when I design stuff I will always try to remove or modify before adding more things = more complex and work, if you take your motor apart you will more than likely find a wavy spring washer, inside one of the end plates, it's usually in the back plate and, it usually pushes on the outside of the ball bearing, this is why your motor shafts have end play, the manufactuer will use this spring washer instead of machining the motor end plates accurately, by replacing this washer with the correct thickness shim or washer will eliminate this end play from the motors
Nick
http://www.rockcliffmachine.com

[boblon]

Originally Posted by lgroulx200 A solid rod is stronger then a tube of the same diameter. But increasing the diameter of a tube or rod greatly increases the strengh.

Does 'stronger' include stiffer? It kind of made sense to me that a pipe would be more rigid when I read it on this forum, but hey, what the heck do I know.

I make no bones about being a noobie to this game.

Thanks,
BobL.

[lgroulx200]

Originally Posted by boblon Does 'stronger' include stiffer? It kind of made sense to me that a pipe would be more rigid when I read it on this forum, but hey, what the heck do I know. I make no bones about being a noobie to this game. Thanks, BobL.

Hi BobL,

Yes, I should of said stiffer.

eg.

Take a 20" steel 1/2" steel rod, pin the ends and hang a 100 lb weight from the center. The rod should bend about .25".


Now take a steel 1" X .065 tube and pin the ends, add a 100 lbs from the center. The tube should bend about .036".

They both have a area about .19 but the tube is much stronger and stiffer.

Larry

[kiwichris]

Hurro,

Thanks for the replies.

I might think about the dimensions a bit more, as I'm going to be on a tight budget with this, and I already have the 20mm rods. Ideally I'd like to put a full sheet of balsa wood down on it, but thinking logically about that I'd need a 72" + long machine. Hmmmmm, I really didn't think that through all that well, did I?

I hadn't thought that the larger steppers would have the spring washer setup in them, I'll take one appart and have a look, thanks for that hint.

Cheers, Chris H.

[rockcliff]

Originally Posted by kiwichris Hurro, Thanks for the replies. I might think about the dimensions a bit more, as I'm going to be on a tight budget with this, and I already have the 20mm rods. Ideally I'd like to put a full sheet of balsa wood down on it, but thinking logically about that I'd need a 72" + long machine. Hmmmmm, I really didn't think that through all that well, did I? I hadn't thought that the larger steppers would have the spring washer setup in them, I'll take one appart and have a look, thanks for that hint. Cheers, Chris H.

Hi Chris
I am planning to add my version of a Flying Gantry style router, to the plan set in about 2 weeks, a flying gantry will save space, but will usually not be as strong and a little more complex to build compared to a moving table design, a FG style router will shares one common set of rails/slide for all 3 axis's but they do save space with larger machine payloads like yours you should see the additional model added to the plan set soon. with the additional two commercial models added this week, it will now bring the total to 8 models to select from, something for everyone.
Nick
http://www.rockcliffmachine.com

[gmfoster]

Originally Posted by rlrhett Was there ever a follow up to the post asking for more information on the Seamless Mechanical Tubing? Is there a McMaster part for them? Have the guys at Rockcliff incorporated the tubing as a potential alternative in the plans? Will anything called "seamless tubing" work, or what should we be looking for? Thanks!

One mail order source of Seamless tubing is "Aircraft Spruce &Speciality COmpany..

www.aircraft-spruce.com

They have round and square in 4130 as well as a heap of other stuff that could be useful in home built routrers. They cater to the homebuilt aircraft srowd and have a great paper catalog..

Garry

[boblon]

Originally Posted by gmfoster One mail order source of Seamless tubing is "Aircraft Spruce &Speciality COmpany.. www.aircraft-spruce.com They have round and square in 4130 as well as a heap of other stuff that could be useful in home built routrers. They cater to the homebuilt aircraft srowd and have a great paper catalog.. Garry

Thanks

BobL.

[kiwichris]

Originally Posted by rockcliff Hi Chris I am planning to add my version of a Flying Gantry style router, to the plan set in about 2 weeks, a flying gantry will save space, ........ http://www.rockcliffmachine.com

Hi-ho,

Thanks for that, but from a complexity and rigidity point of view I decided a fixed gantry style of machine was probably more realistic for me last time round I got keen.

Although, given how simple your fixed one looks, I might be converted. :-)

What type of X (long) guides are you looking at? I have quite a bit of this 20mm rod, which will be good for the Y and Z, but a 36" X on a FG type machine would require quite a bit of rigidity/strength as it's got most of the machine weight on it...

Cheers, Chris H.

[kiwichris]

Originally Posted by lgroulx200 Take a 20" steel 1/2" steel rod, pin the ends and hang a 100 lb weight from the center. The rod should bend about .25". Now take a steel 1" X .065 tube and pin the ends, add a 100 lbs from the center. The tube should bend about .036". They both have a area about .19 but the tube is much stronger and stiffer. Larry

You don't have a link or refernece for those calcs do you? Looking at Nicks comments on making a flying gantry version of his design it'd be interesting to be able to do some maths on different sized pipe/rod...

Cheers, Me.

[Jay C]

Originally Posted by kiwichris I hadn't thought that the larger steppers would have the spring washer setup in them, I'll take one apart and have a look, thanks for that hint. Cheers, Chris H.

Careful, if you take a stepper apart, it ruins them. At the very least you'll lose some of the magnetization. I read this on a manufacturer's website, but can recall which one. All the steppers I've seen aren't meant to be taken apart either.

FWIW,
Jay

Update: found this: http://www.sdp-si.com/D785/PDF/D785MTR094.pdf
Do not disassemble motors. A significant reduction in motor performance will result.

[hllrsr]

Hey guys,

Seamless mechanical tubing (or SMT) is used for all sorts of things like bike frames, hydraulics, and my personal favorite (sp?) race car chassis....anywhere weight, stiffness, and strength are required. Mechanical tubing (please note, NOT PIPE!) is also available with a welded seam in one side, from when the material was rolled to make a tube, this is also usable but it usually doesn't have the same dimensional tolerances that SMT does. SMT is mandrel drawn, and the tolerances are usually in the TENTH'S of thousands (.0001 to .0009"), where piping can be in the area of +/- .060" and seamed is usually +/- .020" and not completely round.

If you have a metal supplier or industrial hydraulic shop in your area, either they will have it or they can send you to where you can get it.
I'm using 1" o.d. .120" wall SMT for my long axis rails, as I am going longer on my bed than I can get ground rod at a reasonable price for. $7+ /ft for rod -vs- less than a buck/ft for tubing. BTW, regardless of who you get it from, ask them for NON certified tubing, the price difference will absolutely scare you!!

Also, at a rail length of 51", I have (visibly) much more sag in the rails using 1" ground, pre-chrome shafting than I have in the tubing, almost 3/16" with no load. Checked this one out at work using a pair of Vee blocks on the granite table.

If you stick to the plans for your first machine, it should go together nicely as is. I'm moding the design to suit my own preferences, as I have quite a few successful lower cost DIY builds done already, to give me some idea of what will work -vs- what is likely to give me ulcers.

BTW, maintaining and rebuilding CNC's is also a good part of my day job.

HTH,

Iain
Maintenance Supervisor
Weldco Beales (Ontario) Mfg

[boblon]

Now that's some information I can use. I've got a list of metal suppliers in my area and I'm hoping one of them will have some usable material. Now at least I will have a much better idea of what I'm going to ask them for.

Thank you Iain !

BobL.