Where can I buy M2 x 50mm screw?

Hello.

Like the subject line says, where can I find M2 screws which are 50mm long? I've searched internet but the closest one I could find is 40mm long.

I've picked up a couple of cheap cooling fans for my motors. They have 4 screw hole, one on each corner, and their locations happen to match perfectly to the screws on the back of the motor.

This is great since the only other ways to mount/attach the fan to the motor will be something not as elegant - like wrapping a thin wires around it or using tape/glue.

So I unscrewed one of the screws from the motor. It's 40mm long and I can feel that only the tip of the screw catches on something when it's screwed into the motor. The fan is 10mm thick and the screw holes on the fan don't have any countersink. In other words, for me to use the screw holes on the motor to attach the fan, I need screws which are 50mm long.

Does anyone know where I can find M2 x 50mm screws?

Thank you.

Edited 2 time(s). Last edit at 08/04/2013 01:03PM by Yamster.

I may have to put a fan on my motors, so I checked after reading your post. The screws on mine are 3 mm, or M3 x 40 mm.

Stupid question, but are you sure yours are really 2 mm?

BTW, I plan on using only two diametrically oposite screws to hold the fan in place, that will be strong enough for a small plastic fan.

---

Yvan

Singularity Machine

Yvan Wrote:
-------------------------------------------------------
>
> Stupid question, but are you sure yours are really
> 2 mm?
>

You mean the diameter of the screw?

I have measured the diameter of this M2 screw and its diameter came out to be 0.115 inch. I checked the internet on the specification of M2 screw, and they are saying it's radius should be 0.058 inch (= 0.116 inch diameter), so they are pretty much the same.

I just converted this number into metric, and it turns out to be 2.9464mm... I wonder if that means M2 screws and 3mm screws are vitually the same thing...

Hmm.. I just re-checked the web site I got the diameter info, and now I wonder if I misunderstood the chart...

[www.tribology-abc.com]

Seems like the number followed by M simply is the diameter in mm? So, I guess I should've been looking for M3 screw, not M2 screw, right!

Thank you Yvan for raising this question - I could've been in hunt for a wrong screw if it wasn't for you!



Yamster Wrote:
-------------------------------------------------------
> Yvan Wrote:
> --------------------------------------------------
> -----
> >
> > Stupid question, but are you sure yours are
> really
> > 2 mm?
> >
>
> You mean the diameter of the screw?
>
> I have measured the diameter of this M2 screw and
> its diameter came out to be 0.115 inch. I checked
> the internet on the specification of M2 screw, and
> they are saying it's radius should be 0.058 inch
> (= 0.116 inch diameter), so they are pretty much
> the same.
>
> I just converted this number into metric, and it
> turns out to be 2.9464mm... I wonder if that
> means M2 screws and 3mm screws are vitually the
> same thing...

I get them from my local but and bolt shop. They are a shop that specializes in nuts and bolts. Google name of closest large town gto you followed by but and bolt.

However, I would first ask your self why are your motors running so hot? I have 60 oz-in motors on my prusa i2 driven by pololus on a ramps 1.4 and my motors run just slightly above room temp. You have to hold your hand on them for fi e seconds to even really feel the temp difference.

If using pololus, have you checked your v-ref?

Yamster, glad I could help! M3 x 40 mm is not hard to find, some are on ebay, but the shipping might be silly.

---

Yvan

Singularity Machine

That's a very good point indeed. As a matter of fact, I've been tweaking the current setting of the Pololus during the calibration (sometimes I suspected the poor printing quality is due to lack of the current), and I've just re-adjusted the current setting again.

After the last adjustment, Y and Z motors stay cool throughout printing, and X and Extruder motors get warm/hot after a while (still a big improvement from the previous settings, where I got all motors got pretty hot right after the printing started).

I basically followed the instructions from [reprap.org] - start from pots on the Pololus all the way left, keep turning the pot 1/8 of turn until the motor starts running, and turn another 1/8 turn after that point. However, after hearing that all your motors do not get heat up much, I will try to reduce the current on my X and Exturter motors to see if I can keep them cool.


appdev007 Wrote:
-------------------------------------------------------
>
> However, I would first ask your self why are your
> motors running so hot? I have 60 oz-in motors on
> my prusa i2 driven by pololus on a ramps 1.4 and
> my motors run just slightly above room temp. You
> have to hold your hand on them for fi e seconds to
> even really feel the temp difference.
>
> If using pololus, have you checked your v-ref?

Well, actually what I need is M3 x 50mm, not M3 x 40mm.

Anyway, I found an online supplier which sells a pack of 10 M3 x 50mm for $5.09... and you were right, the charge on the cheapest shipping option was $2.66.. LOL

I didn't even bother to find a cheaper deal and placed an order with them, since it will only be a matter of a buck or two, if I can find a better deal that is.



Yvan Wrote:
-------------------------------------------------------
> Yamster, glad I could help! M3 x 40 mm is not hard
> to find, some are on ebay, but the shipping might
> be silly.

That's the one I followed first too. They should put a link to the pololu page from the calibration page. Try setting them to 0.4v by doing just like the pic shows. If they won't move well after that then turn them up in 0.01 volt increments. BTW, that 0.01 is hard to achieve, you just basically put slight pressure on the screw driver without actually turning it. If you get up toward 0.5v before they start working correctly, shut the printer off and make sure that axis can be moved smoothly by hand. Mine were OK with the printer off. It turned out the printer was drawing too much current from the cheap PC PSU is was using. I now have one PC PSU hooked the the 5A terminal and a second hooked to my 11A terminals. Printer runs great now.

Yamster Wrote:
-------------------------------------------------------
> That's a very good point indeed. As a matter of
> fact, I've been tweaking the current setting of
> the Pololus during the calibration (sometimes I
> suspected the poor printing quality is due to lack
> of the current), and I've just re-adjusted the
> current setting again.
>
> After the last adjustment, Y and Z motors stay
> cool throughout printing, and X and Extruder
> motors get warm/hot after a while (still a big
> improvement from the previous settings, where I
> got all motors got pretty hot right after the
> printing started).
>
> I basically followed the instructions from
> [reprap.org] - start from
> pots on the Pololus all the way left, keep turning
> the pot 1/8 of turn until the motor starts
> running, and turn another 1/8 turn after that
> point. However, after hearing that all your
> motors do not get heat up much, I will try to
> reduce the current on my X and Exturter motors to
> see if I can keep them cool.
>

Edited 2 time(s). Last edit at 08/05/2013 01:29AM by appdev007.

Please note I have posted twice in a row. Be sure to read the one above this.

I pay pennies a piece for my M3 bolts a my local nut and bolt place. Shipping should be more than the bolts.

Yamster Wrote:
-------------------------------------------------------
> Well, actually what I need is M3 x 50mm, not M3 x
> 40mm.
>
> Anyway, I found an online supplier which sells a
> pack of 10 M3 x 50mm for $5.09... and you were
> right, the charge on the cheapest shipping option
> was $2.66.. LOL
>
> I didn't even bother to find a cheaper deal and
> placed an order with them, since it will only be a
> matter of a buck or two, if I can find a better
> deal that is.
>

If you screw a fan to the back of a motor, with no gap, it will not do anything as there will be nowhere for the air to go. You need to leave a gap with a similar cross sectional area to the bore of the fan.

With the correct motors and current setting fans are unnecessary.

---

[www.hydraraptor.blogspot.com]

Nophead, LOL, yes that is correct! Somehow I forgot to mention that a spacer is needed. If you look up "nema 17 fan mount" on Thingiverse you get several. Many seem determined to block air flow as much as anything though. My intention is to install simple spacers or standoffs under the two screws holding the fan.

BTW, I'm operating under the assumption that this would be needed in an enclosed printer with air tempuratures well above room temp, such as #4 that I have started building.

---

Yvan

Singularity Machine

Hmm.. I am getting great info here - as always!

I can't locate my multimeter, so until I can find it I will rely on the old method of turning-the-pot-a-little-bit-and-see-how-it-works method. :p

But still, I would not have known how little of turning on the pots can make a big difference if I didn't read these replies... I guess adjusting the pots by 1/8 turn could actually be too much.


So, now I know if have had all the motors properly tuned, then I would not need cooling fan. Will the extruder motor (I think it's the busiest motor of all) stay cool enough (below 50C?) to be mounted on extruder which is made with PLA?

I heard PLA is stronger and easier to work with, but it does not withstand high temperature as well as ABS. Being a novice RepRapper, I've been exclusively working with PLA so far.

I really want to try out different variation of the extruder design (mine vibrates too much), but I wonder if I need to learn how to print using ABS first.

I have to say I went straight to ABS, I felt PLA was a bit too marginal for some applications. On a number of occasions I've seen people stuck with a critical part such as a PLA X carriage warping. I had a PLA extruder body (part of a Techzone kit) which was starting to warp, gradually throwing the gears out of alignment. I have not seen the same with ABS replacements I've made.

I think making a few parts with ABS might be a good trick to learn

---

Yvan

Singularity Machine

You really want your x carriage and extruder to be ABS otherwise it's probably sure to warp at some point. I think you will find PLA is fine for most of the other printer parts and in some cases might be better.