[Ed_R]

I'm sure hoping that 116 ounces is enough to push a trim router through maple and mahogany in 1/8th inch depth passes and using 1/4 and 1/.8 inch bits. Anyone tried it?

[ger21]

There are a lot more factors involved than you mention. What kind of screws you're using? How efficient are they? How much friction does the machine have? Does it bind anywhere? And how fast do you want to go. Sure, they'll more than likely work, but will they do it at the speeds you want?

Plenty of people here have built routers with 100 oz motors, so you should be fine.

[Ed_R]

gerry, you always tell me what I need to know.
As far as I can tell, I've got ACME 12/10. They work ok, fairly smooth and I can get some fairly decent speeds with no loads. I have had a tough time getting any GCode I can trust to cut wood with but the machine seems to move failry well without cutting anything.
My question was sparked because I know that 116-ounce-inches of torque works out to about 7 foot-pounds of torque and that just doesn't seem like much push at all. I'm trying to decide if I want to buy the NEMA 269 ounce motgors even before I see what these 116 ouncers will do. I suppose I should hold off and see eh?
Your statement that lots of people have built routers with 100-ounce motors gives me a generally positie answer though. MAybe I'l just buy lunch instead

[ger21]

116 oz -in is actually 0.6 lbs-ft of torque. You have to divide by 12 because you're converting inches to feet.

[Ed_R]

I hate you.


That low of a torque number is scary.

[Fifty_ohm]

If it makes you feel any better I have the Laserjet II steppers (115 oz/in) driving 1/4 20 all-thread leadscrews. I accidentally ran a 3/8" round nose bit 1/4" deep into a piece of 2x4 at 20ipm (and through a knot in the wood to boot). This flexed the whole system but those steppers kept pushing without losing steps. You'd be amazed at what a little torque multiplies into when you take into account the screw it's turning.

[Ed_R]

I guess I'll be OK then. Thanks!

[buscht]

I agree that you can do what you want with 116 oz-in stepper motors. I have cut .34 deep passes with a .020" stepover using a 1/8" ball nose end mill at 20" per min.

Going to the 270+- oz-in steppers allows you to cut at 60" per min, which is actually better for the rpm's of a small router. You get less burning on the tool for better tool life.

[Ed_R]

I'll cut something with the less powerful motors, and if it byrns the tool or the wood too much then I'll ..um, step up to the bigger ones. THanks a lot for the discussion!

[sdantonio]

Hi Ed,

You can always trade up later too. Build the router, if it doesn't suit your needs then replace the motors and sell the old ones on ebay or out here. The old ones would be great for someone who wants to build a plotter or foam cutter.

But once you build it you may be pleasantly supised to find they work fine.

Steven

[Ed_R]

Router's been built since mid-February, Steve
I'm about to dig into cycloid and some other fun stuff. Have you found a way to change a curve in Rhino after you've defined it?

[sdantonio]

Hi Ed,

Change a curve in whay way. mathematically as script like application... no, I haven't looked into this yet. In a lot of ways setting up the rosswise archings as a script would be a lot easier and more exact.

Otherwise you can just cut (CTRL-T) and remove the old one and then preplace it with the new curve.

If you need the mathematical equation for the cycloid I have it at home. It's pretty easy (remember, the word "easy" in this sentence is being used by a physicist... not a normal person )

Steven

[Ed_R]

I never knew physicists weren't normal people, but now that you mention it, they are kinda wierd aren't they?
John Nash wasn't a physicist was he?

I have several surfaces, and I'd lilke to change the edge curves on them- sort of bend the sheet, as it were.

[Ed_R]

GOt it cutting wood, it seems top be strong enough but I'm getting tremendous amounts of step-skipping. GOing through all the motions to isolate now.

[Fifty_ohm]

Make sure you setup the motor accel/decel and top speed correctly. I was trying to drive mine too fast and it caused it to miss steps. I think the rule of thumb around here is find the speeds that you can move at full speed without losing any steps under no load condition and then back off 20%. Worked for me.

[Ed_R]

I was at 10K top speed in Turbocnc, dropped it to 5K, 2K acceleration. Still skipping. I'm at 2750 with a 2000 accel now. About a third of the way through a run - so far no skips, but no load yet either, it's just going back over what it already did.