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View Full Version : FOR SALE: 2x 2005 C7 Ballscrew 1450mm Length with Ballnuts + FK/FF mounts and motor coupler



Shinobiwan
29-12-2012, 06:06 AM
2x RM2005 C7 Ballscrew 1450mm length and SFU2005 ballnut complete with FK (including the lock nut) and FF mounts. Also includes a flexible motor coupler with 8mm dia bore to fit standard nema 23 shaft.

You can consider these new as although they were fitted to my machine its never cut anything. Ideal for a 4ft axis.

Delivery is an option but will be expensive because of the weight and length. Would prefer collection if possible.

Bargain at 60 each or 110 for the pair. You'd normally pay 200+ for these from China not to mention the chance of VAT and import duty on top of that.

Here's a sketch showing the exact dimensions

7785

And a couple of images

7782

7783

7784

Mad Professor
29-12-2012, 11:11 AM
If they where 2010's I would of ripped your arm off.

I will have a think about your 2005's, and speak to the boss (wife) about it.

Pheet
29-12-2012, 01:52 PM
Hi
I'm interested in the ballscrews and would appreciate some advice. I'm building a small machine approx 800mm x travel and 600 y travel. Gantry mass approx 20kg (+/- 2kg) with spindle. Would 2005's be up to the job?. i haven't got around to the calcs yet but for my machine I can just machine them to the right length.

Thanks in advance for any help / advice you may be able top offer

Cheers
Leigh



2x RM2005 C7 Ballscrew 1450mm length and SFU2005 ballnut complete with FK (including the lock nut) and FF mounts. Also includes a flexible motor coupler with 8mm dia bore to fit standard nema 23 shaft.

You can consider these new as although they were fitted to my machine its never cut anything. Ideal for a 4ft axis.

Delivery is an option but will be expensive because of the weight and length. Would prefer collection if possible.

Bargain at 60 each or 110 for the pair. You'd normally pay 200+ for these from China not to mention the chance of VAT and import duty on top of that.

Here's a sketch showing the exact dimensions

7785

And a couple of images

7782

7783

7784

Shinobiwan
29-12-2012, 02:51 PM
Sold to the man with the hobnobs (John).

Shinobiwan
29-12-2012, 03:03 PM
Hi
I'm interested in the ballscrews and would appreciate some advice. I'm building a small machine approx 800mm x travel and 600 y travel. Gantry mass approx 20kg (+/- 2kg) with spindle. Would 2005's be up to the job?. i haven't got around to the calcs yet but for my machine I can just machine them to the right length.

Thanks in advance for any help / advice you may be able top offer

Cheers
Leigh

I know this is academic since they're sold - sorry but I'd be tempted to go for 2010.

I'll be honest and say that I've swapped these out on my machine for 2010 as they're just too slow for cutting wood on the end of a nema 23. These small motors only run up to about 1000rpm with reasonable torque. Spinning at that speed the most you can reliably expect is about 5m/min traverse but little torque left for cutting. This is fine if your doing a lot of metal routing where your usually around 1m/min or less but for MDF like I do its just not fast enough where you need to be cutting 4-5m/min usually.

Depends what your cutting the most really! Judging by your gantry weight its not a lot so doubt it will be for metal. If your mostly cutting wood go for 2010 or even 2020 if your using the latest digital drives and suitable motors as these have very fine resolution using realtime microstepping adjust and signal input interpolation. If its metals then 2005 or 2010 would be fine.

JAZZCNC
29-12-2012, 03:06 PM
Thanks for letting me know . . mate.:neglected:

Staff Edit: Comment removed as per the forum rule:

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Jonathan
29-12-2012, 03:26 PM
I considered buying them, for about 20 seconds.
The only thing this size ballscrew is good for is maybe a big milling machine or lathe. For other machines, like CNC routers, the forces on the ballscrews are so low that you don't need the slight increase in stiffness gained from using a RM2005 screw, hence you're much better off sticking with 16mm ballscrews and the appropriate pitch. The price was good, but to me that's not enough to counter the poor performance you'll get on a router with these, especially since it could increase the cost of the electrical parts. Presumably John S has a big machine to convert...


( That Old bastards not about any more and he's still beating me to it.!! )

Hmm really?

7793

JAZZCNC
29-12-2012, 03:51 PM
The only thing this size ballscrew is good for is maybe a big milling machine or lathe.

Or for replacing a worn ballscrew on a machine of a very similar size like mine.!!!

Jonathan
29-12-2012, 04:14 PM
Or for replacing a worn ballscrew on a machine of a very similar size like mine.!!!

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.

Shinobiwan
29-12-2012, 04:57 PM
The only thing this size ballscrew is good for is maybe a big milling machine or lathe. For other machines, like CNC routers, the forces on the ballscrews are so low that you don't need the slight increase in stiffness gained from using a RM2005 screw

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.


Presumably John S has a big machine to convert...

Or he's chopping them up into lots of little screws ;) More likely though is he'll put them in his cnc spares stash and leave them for a rainy day. The man has enough parts to set up a cnc factory.

Shinobiwan
29-12-2012, 04:59 PM
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
29-12-2012, 06:11 PM
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
29-12-2012, 07:13 PM
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.:thumbdown:

John S
29-12-2012, 07:25 PM
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.:thumbdown:

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.
29-12-2012, 07:54 PM
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
29-12-2012, 07:55 PM
It looks like there is honour amonst thieves!!!

Web Goblin
29-12-2012, 09:05 PM
John maybe you could ransome them to Jazz to get back some of your gear, or was that the other way round?

Shinobiwan
29-12-2012, 09:40 PM
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
29-12-2012, 10:36 PM
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
29-12-2012, 10:49 PM
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.:thumbdown:

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.

Shinobiwan
29-12-2012, 10:53 PM
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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Cheer's John. I understand its not worth the trip just for the Z axis so no problem. I'll wait to hear from Jazz and see if he want these screws. If not you can still have them mate.

John S
29-12-2012, 11:09 PM
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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Come on Lee, been back two minutes and you are already wielding the red pen.
It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??

wilfy
29-12-2012, 11:14 PM
Come on Lee, been back two minutes and you are already wielding the red pen.
It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??

to be fair john he did also edit jazz's earlier comment about you as well where he called u an old bastard... between friends you know it's a joke but from an outsiders point of view you do question sometimes if things are jokes or not

John S
29-12-2012, 11:23 PM
I don't need Lee to fight my non existent battles, all big boys here. I get on well with Jazz, it's all taking the piss in good fun.

Just some don't have a sense of humour..................................

I'd feel happier with this red pen application if he reigned his so called moderators in a bit better.

Jonathan
29-12-2012, 11:46 PM
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.

Right, so you have said let:
acceleration =1000mm/s^2=1m/s^2
velocity = 10m/min = 10/60= 0.167 m/s (not actually required for the initial calculation)
mass = 80kg

It's just newtons 2nd law, so F=ma=80*1=80 Newtons (equivalent to lifting about 8.2kg), so not far off my earlier estimate.

From the motor's point of view it's not 80N, since we have to consider the ballscrew in between. The ballscrew gives the motors a huge mechanical advantage. The relevant formula, which can be derived from considering the ballscrew as a ramp, is:

T=F*p/(2*pi*e)
Where T is the torque, F is the force applied to the nut, p is the ballscrew pitch (so 10mm=0.01m) and e is the efficiency (about 0.9). So chuck the numers in:
T=80*0.01/(2*pi*0.9)=0.14 Nm

So changing direction at 10m/min and 1m/s, as you describe, only translates to an extra 0.14Nm torque on the ballscrew, compared to going at a constant speed and 80N force on the ballnut.

Shinobiwan
30-12-2012, 12:04 AM
Thanks for that.

Does that calculation include counteracting the inertia from the screw turning too? I forgot to mention that. I'm interested to see what the total load would be.

Lee Roberts
30-12-2012, 12:24 AM
Come on Lee, been back two minutes and you are already wielding the red pen.
It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??

John I haven’t seen that post of Jazz’s, but if it’s a comment about himself then I don’t think it would/could be perceived in the same way and would lead to anything else.


to be fair john he did also edit jazz's earlier comment about you as well where he called u an old bastard... between friends you know it's a joke but from an outsiders point of view you do question sometimes if things are jokes or not

I did yes, i also then sent this PM to D.C after:


I think those comments were ment in jest D.C as they both know each other off the forum, i know how it reads some times though and wish they would stop talking/posting in this way because not everyone knows them both that well and it dose look bad at times.

We've got it in hand though, thanks.

.Me


I don't need Lee to fight my non existent battles, all big boys here. I get on well with Jazz, it's all taking the piss in good fun.

Just some don't have a sense of humour.........

I know that, some do know that, allot of people dont know that and that's where i come in. A joke is only funny when everyone in the "room" is in on it.

There's no Red Pen, No one has done anything wrong (as such), im not tapping the badge or picking on anyone. My kids are having a sleep over with their cousins the age range is 3 - 10 so you can imagine what i'm up against, as such im up and down from my laptop like a yoyo, if i'd of had more opportunity i was getting ready to type up a PM to you and Jazz just to let you know why i had removed the comments and there was no "hard feelings" to keep it simple.

I've kept this short and sweet so i can get it in before it all gets blown out of context and people start chipping in, Merry Christmas John its good to see you active again.

.Me

JAZZCNC
30-12-2012, 04:02 PM
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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Discuss or link to objectionable and/or offensive topics. This is not permitted and includes but is not limited to: things of a violent nature, pornography, sexism, racism and/or other discriminatory subjects, this includes things considered to be as a “joke”. Religious and/or political discussions or anything considered to be of the same nature are not appropriate for these forums and will be removed from public viewing.



Well Mr Stevenson I saw your Post before the SS jumped in and I must say I've never been so insulted in my life good Sir.

So on this matter request you meet me Sir in the Central reservation of the M1 for a dual at dawn. (Or when ya eventual fire the zimmer up.!!)

Bring the Axle grease because the loser gets Rm2005 inserted side ways and Z axis up his Pi$$~.!! . . . . Now F@~% O%% You Old B%@~% and happy Xmas mate. .:surprise: X X X
X X X X X X X X X X X X X X X X X X

Now I've got a important and just has relevant Calculation for Jonathan.?

Was in workshop Tuther day and waiting for Job to finish when I felt another Jobbie coming on and while there Nipping the Old vice Cheeks started to wonder just how many Nm of force could be applied thru Cheek power alone.? . . . . Obviously realise this will be a rising rate has desperation sets in so some parameters will be needed..?

So lets say when at the Turtle point of 15st Fat B@~&$ erds thrust curve when powered by a full Vidaloo madras.?

Oh and what will be the stall point time curve so know how many liner meters of paper for Clean up.? :joker:

John S
30-12-2012, 04:38 PM
Well Mr Stevenson I saw your Post before the SS jumped in and I must say I've never been so insulted in my life good Sir.



You have obviously not been round much then.

If we are talking about the central reservation on the M1 than lets use the bit just below J27, the Mansfield turn.

Rather partial to that bit after having removed about 30 metres of it in a wrecker one day doing a slow spiral from slow lane to central reservation.

So after all the "Pi$$~.!! . . . . Now F@~% O%% You Old B%@~% and happy Xmas mate. .:surprise: X X X
X X X X X X X X X X X X X X X X X X"

Are you having them ?

JAZZCNC
30-12-2012, 04:46 PM
Are you having them ?

Yes I would have liked them or at least the chance first but you have them Mate has a Xmas and welcome back present.
Tried ringing Ant to tell him but not around so if ya speak before I do let him know.

Oh It's nice having you back around Buddy.!

Shinobiwan
30-12-2012, 06:20 PM
Rather partial to that bit after having removed about 30 metres of it in a wrecker one day doing a slow spiral from slow lane to central reservation.


Wasn't a passat estate was it? Saw a nasty one between 26 and 27 a couple of months ago.
So what's happening with these screws? You definitely don't want them Dean? Don't want you coming back to me saying I'm a useless inconsiderate twat at a later date haha :beer:

WandrinAndy
30-12-2012, 06:24 PM
.... started to wonder just how many Nm of force could be applied thru Cheek power alone.? . . . . Obviously realise this will be a rising rate has desperation sets in so some parameters will be needed..?

Afraid I don't have a formula at hand but would like to suggest that it include a parameter that caters for dwindling power over age, as I'm convinced I canna hold them in as well as I used to do!

Shinobiwan
30-12-2012, 06:28 PM
Afraid I don't have a formula at hand but would like to suggest that it include a parameter that caters for dwindling power over age, as I'm convinced I canna hold them in as well as I used to do!

Really glad I choose to have sunday dinner on my lap sat in front of the pc reading this lol

Web Goblin
30-12-2012, 06:48 PM
Yes nice to have you back John.
Pmsl at the comments.

JAZZCNC
30-12-2012, 08:08 PM
So what's happening with these screws? You definitely don't want them Dean? Don't want you coming back to me saying I'm a useless inconsiderate twat at a later date haha :beer:

No I'll call say that now mate to avoid any confusion.!! . . . . . Let the Old and kindly gentleman have them.:livid: ( LEE is that better for the Papy sensitive b@~%&rds out there.!!)

John S
30-12-2012, 08:20 PM
. Let the Old and kindly gentleman have them.:livid:

Sht............ just put the red coat and white beard away for another year, have to drag it out again now................... Sigh.

Ant, I'll get in touch tomorrow, got to shoot up to N Derby tomorrow, Gert's niece is in hospital having her Barclaycard surgically removed.

Not a wimpy Passat estate it was a eight wheeled recovery truck towing a broken down Sternol oil truck, some twat in an artic fell asleep and ploughed into the back of both of use. The oil truck went down the bank into that lake on the left and i di a very very slow [ or so it seemed ] two and a half pirouettes and smacked into the barrier, with the 8 wheeler on it's side.

Only saving grace was I'd got brown trousers on that day............

Shinobiwan
31-12-2012, 04:58 AM
No I'll call say that now mate to avoid any confusion.!! . . . . . Let the Old and kindly gentleman have them.:livid: ( LEE is that better for the Papy sensitive b@~%&rds out there.!!)

All that f%$king moaning and you don't want them now! lol You don't want these anyway, get some 2010 now that Chai is doing them. Next bunch of cast offs I'll give you a call first.

Right John, your back on then. I'm off down to Bulwell in Notts for new years tomorrow around 2ish and back Wednesday morning. I can take the parts down there if you want to collect since its closer. If you turn up on Tuesday be warned that I'll probably be wrecked still but I'm sure you'll have seen far worse! If not, it'll have to be Wednesday onwards. I'll PM you my mobile number any way mate.

JAZZCNC
31-12-2012, 10:31 AM
Next bunch of cast offs I'll give you a call first.

Don't F@~& bother.!

Shinobiwan
31-12-2012, 02:42 PM
Don't F@~& bother.!

Keep ya pants on. That was meant as a joke mate!