2x 2005 C7 Ballscrew 1450mm Length with Ballnuts + FK/FF mounts and motor coupler

[Shinobiwan]

Perhaps, but we both know you'd me much better off getting 1610 or 2010 for a router this size. 325 USD including postage (but not customs) gets you two RM2010-1500mm, so yes a bit more but well worth the extra money if you are swapping since you can keep the same end-machining, unlike with 1610. Wearing out the ballscrew would take some doing anyway, I gather it's generally the nuts that fail first.

Got two RM2010 at 1450mm with end machining and ballnuts from chai for $218 including shipping. So 325 is very expensive where ever your buying those from.

[Jonathan]

Its not slight when your spinning them at 1000rpm+ At 1.45m I've got a 1610 on the Y axis and it just starts to show whip at 10m/min, at 14m/min its like jelly! You won't run at these speeds of course but for cutting wood you want in the range of 4-7m/min depending on the cutter dia and flutes along with DOC. Unless of course your spinning the nut but I'd still go 2010 at those lengths anyway. The cost difference is minimal for the added peace of mind.

The cutting force on a CNC router is a few tens of newtons, even when taking 'heavy' cuts in wood or aluminium. There's an additional force when acceleration so lets say 100N. The RM1610 ballscrews are rated for something like 7800N for one million revolutions, so operating at 100N they will last for a very long time. Hence you don't need a bigger screw unless critical speed is an issue, which according to your experiment and the calculation it isn't for this length (1450mm) and RM1610.

Got two RM2010 at 1450mm with end machining and ballnuts from chai for $218 including shipping. So 325 is very expensive where ever your buying those from.

I did not say that I had bought any at that, or any, price. That was the first seller I found on ali-express who has RM2010. Last time I checked Chai doesn't sell RM2010 and Jazz posted only a few days ago saying the same. So where did you get your RM2010, or are they actually RM1610?
Either way my point is valid - RM1610 or RM2010 is a much better choice for this length for the vast majority of machines built on this forum. If John S has got a use for them then good for him, since he's just got a good deal.

[JAZZCNC]

Perhaps, but we both know you'd me much better off getting 1610 or 2010 for a router this size. 325 USD including postage (but not customs) gets you two RM2010-1500mm, so yes a bit more but well worth the extra money if you are swapping since you can keep the same end-machining, unlike with 1610. Wearing out the ballscrew would take some doing anyway, I gather it's generally the nuts that fail first.

Forgot who your talking to here Numb nuts.? . . . . What you think you know your wrong about.!!

This machine has been working fine for nearly 5 years with 2005 and the wear is very slight and possibly in the nut, could even be end bearings I haven't checked yet. Mostly it's down to the fact it's been abused and abused with no protection and run in some shity conditions.!!. . . . . 1610 or 2010 would give me nothing extra I have already that is of any use to me so why would I bother changing now.

It would just have been nice to have had the chance to buy some cheap replacement screws before being offered up to general public considering the involvement I've had with this machine.!! . . . ANT.

[John S]

It would just have been nice to have had the chance to buy some cheap replacement screws before being offered up to general public considering the involvement I've had with this machine.!! . . . ANT.

You need to take everything though, I'm not pissing about wasting diesel to pick 10 bobs worth of gear up.

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[D.C.]

If that was serious and you two are having a tiff and Jazz doesn't want the z-axis, my offer is still open just so long as nobody is going to be mortally offended by it.

[GEOFFREY]

It looks like there is honour amonst thieves!!!

[Web Goblin]

John maybe you could ransome them to Jazz to get back some of your gear, or was that the other way round?

[Shinobiwan]

I did not say that I had bought any at that, or any, price. That was the first seller I found on ali-express who has RM2010. Last time I checked Chai doesn't sell RM2010 and Jazz posted only a few days ago saying the same. So where did you get your RM2010, or are they actually RM1610?

These are RM2010 and from Chai (linearmotion2008). Don't know about previous stock but when I inquired and ordered yesterday he stocks and sells 2010.

Seems there's something handy there. 2010 are now available for a reasonable price!

[Shinobiwan]

The cutting force on a CNC router is a few tens of newtons, even when taking 'heavy' cuts in wood or aluminium. There's an additional force when acceleration so lets say 100N. The RM1610 ballscrews are rated for something like 7800N for one million revolutions, so operating at 100N they will last for a very long time. Hence you don't need a bigger screw unless critical speed is an issue, which according to your experiment and the calculation it isn't for this length (1450mm) and RM1610.

Jonathan, your good with this maths stuff.

I have a gantry that weighs approximately 80kg with spindle. With a decent rate of acceleration let's assume its set to 1000 and 160 steps per in mach with dual RM2010 and 4Nm motors. How much kinetic energy is transferred to the motors when doing a direction change at say 1000rpm or 10m/min? You got to decelerate that 80kg in a very short space of time and I'd hate to think how big this number is going to be or if the motors can even handle that.

[Shinobiwan]

It would just have been nice to have had the chance to buy some cheap replacement screws before being offered up to general public considering the involvement I've had with this machine.!! . . . ANT.

To be honest, when you mentioned this the other day, I thought you were going with 2010 if it came to replacing the screws and gearing down to 1:1. Didn't even enter my head that you might want them otherwise would have given you a shout of course.

Your in luck because John's a true gent and looks like he's willing to step aside so your welcome to them if your still interested by the time you read this. Let us both know ASAP and we can sort the details.