Hi,
I know this post was made almost a year ago but could you please tell me something.

I had an extra cd-rom reader in my the house (a broken ps2 drive) but the shaft seem about one mm less (or less) than the one in my motor (the seller states that it has a 3 mm shaft).

Can this still work? Or its better to look for another cd-rom drive?

Is this the stuff that will work for sure?

http://www.ebay.co.uk/itm/3mm-dia-st...9#ht_630wt_905

Regarding the circlip, what are the correct measures, 3mm or less?


Thanks,

L. Pinho

Originally Posted by lpinho

Hi,
I know this post was made almost a year ago but could you please tell me something.

I had an extra cd-rom reader in my the house (a broken ps2 drive) but the shaft seem about one mm less (or less) than the one in my motor (the seller states that it has a 3 mm shaft).

If it is 1mm less it will not work. The 3mm shafts in the drives are hardened and ground to size, very high precision.

Can this still work? Or its better to look for another cd-rom drive?

Is this the stuff that will work for sure?

http://www.ebay.co.uk/itm/3mm-dia-st...9#ht_630wt_905

The shaft on eBay is not hardened and ground, it is too soft and will not work. The right stuff cannot be cut with a hacksaw, that is why we use abrasive disc in a Dremel tool.

Look at the shafts here:

http://www.headsuprc.com/servlet/the...fts/Categories

See if you can find one there that will fit or that can be made to fit. And they have the clips too. You may have to grind a flat for a grub screw, cut a shaft to length, or make a groove for a circlip. That is the stuff you have to do when they don't sell the right replacement shaft.

I'm going out of town for a couple of days, if you don't get any replies I'll be back Tuesday or so...

Jack

For motors requiring a 5mm shaft, you can get a really good hardened shaft from anyone selling Align 450 helicopters! They come in two grades, the stock shafts are reasonably hard, and the deluxe are really super tempered hardened shafts ( my choice). Still easy to cut with a Dremel, long enough to leave enough for proper flats and collars. FWIW Doug B

Thank for the quick replies Jack,

I'll try to find the proper replacement.

Thanks,

L. Pinho

lpinho

Technobots are where I get my shaft stock from. They ship to the EU as well.

Originally Posted by RobC(UK)

lpinho

Technobots are where I get my shaft stock from. They ship to the EU as well.

Thanks for the information.

How do you identify if the "bar" material is any good for building shaft?

Regards,

L. Pinho

Originally Posted by lpinho

How do you identify if the "bar" material is any good for building shaft?

See the data sheet at the top of the linked page.

http://www.technobotsonline.com/Datasheets/4426-002.pdf

Great piece of information, thanks RobC

Can this thread be turned into a sticky. This is one the most common problems electric flyer pilots run into. Had I known about it I could have saved a bunch of money.

Originally Posted by lpinho

Thanks for the information.

How do you identify if the "bar" material is any good for building shaft?

Regards,

L. Pinho

You have to have a basic familiarity with the different types of material, their condition as far as heat treatment (hardening the metal) and tempering (reducing the hardness to the needed working strength). The final consideration on the shaft is it's size and the precision of the size as how much it will vary in size and how straight the shaft is.

It is just a coincidence that items like precision shafting and some things made for other purposes (high speed steel drill blanks for example) just might happen to have all the desired qualities that will make work for brushless motor shafts. If you read the description of steel drill rod here:

http://en.wikipedia.org/wiki/Bar_stock#Drill_rod

That just happens to describe all the qualities that a motor shaft should have to be a controlled fit in a pair of inner bearing races and also be hard enough and strong enough. To get it to that state and size it was hardened, tempered, and ground to size.

Inner and outer bearing races are also hardened and ground to size with a high degree of precision. The races are basically hardened and ground to a size to be no smaller than their called size and only a small amount larger than the called size.

The final consideration on the shaft is that it's size and the precision match the inner race well. You need a shaft that is precisely sized so as not to be too loose in the bearing race. But it cannot be too much larger either or it will not fit the race or can even damage the race and/or the shaft if they are forced together.

So, in a theoretical case, the 5mm bearing races might have tolerances that will let them range in size from 5.000 mm to 5.003 mm. And the hardened and ground high speed steel drill bland shaft might range in size from 4.999 mm to 5.005 mm. So in the loosest case there will be 0.004 mm of loose play around the shaft and 0.005 mm of interference when the shaft is pressed into the race. You can slide that shaft into place or maybe press it in as a light to medium press fit.

If you buy a lower precision material such as ordinary cold rolled steel 5mm rod (called bright steel in some cases) the rod may be as much as 0.076 mm undersized and as much as 0.076 mm to 0.127 mm oversized. And it can be way too loose or way to tight in the races. So much so that you may hve to risk damaged the race or shaft forcing it into the race.

So the bottom line is that you want to buy shafting that is very close to the desired size and that has very little variation under that size and only a tiny amount of variation over that size.

Jack

Originally Posted by zeroback

Can this thread be turned into a sticky. This is one the most common problems electric flyer pilots run into. Had I known about it I could have saved a bunch of money.

Thanks for your kind words, zero!

The process for that is that people use the report this post button (by the post #) to ask or recommend the moderators to make a thread a sticky. We have done that for a couple of threads there, the KFm discussion threads on the Foamies (Scratchbuilt) for example.

I have mixed emotions about stickies, there can be too many in some cases and they can become seldom used and just tie up space at the top of a forum.

And sometimes a search engine will do a better job of finding threads than a stick willy because the search engine can find the more recent info. The search engine here is just OK and only them if you know how to use it best.

I have hundreds of bookmarks on my browser (firefox) and have those all grouped topically for various interests. But I find that I often use google to find a thread that I know is here somewhere. For example, if you google "rcgroups brushless shaft" it will find this thread. And that works for other threads when know some of the words in the thread title and look for them from computers where I might not have book marks.

So I defer to the members here if they think this is worthy of a sticky or not.

@zeroback,

I noticed today that I had become a RCG Plus Member and it took me a while to figure what that was and what it meant. And in the course I found you had asked that to happen. So thanks for that too!

I think the +Plus thing is still being invented or something. My hat still fits so I guess I'm OK with it.

Jack

Thanks for all that great info. That is exactly why I was thinking about a sticky. I search for stuff by name on RCG that I know is here and it doesn't show up. Now that you mention it I do see allot of Google results showing RCG threads.
As far as RCG Plus goes when I first found this site I thought I had to pay to post pictures, so I subscribed ( not the brightest bulb sometimes) and so by default I landed in the plus world. The mods were asking for suggestions and you immediately came to mind. Your information has been of enormous help to me ( and so many other enthusiasts ) in getting so far so quickly with successfully creating good motors. Thanks again.

Great thread Jack! Any suggestions about what type of drill rod -- air, water, or oil hardened?.

Originally Posted by vtdiy

Great thread Jack! Any suggestions about what type of drill rod -- air, water, or oil hardened?.

Drill rod is often a little over-sized and often intended for making various lower precision shafts and parts. So if you try to use drill rod for shafts, it may be too large for the inner bearing races.

But if you buy drill blanks they will be hardened and ground to a precise size and finish. Typically drill blanks are sized to -0 and +0.0005" tolerances and will be a perfect fit on the bearing races. So the latter is the better choice for motor shafts:

https://tinyurl.com/yda2kelj

The place there, Essentra, used to be called Reid Tool Supply...

If you phone them the ladies that run the phone order desk will usually handle a small order promptly and also set you up with a cheaper and faster shipment by mail instead of UPS.

Those can be had in in and metric, for the most part the 1/8" or 3.175mm is the only Imperial shaft sized needed. Otherwise the metric sizes are what is needed.

If you find a drill blank slighty tight in a race, chuck it in a drill motor and polish it with 600 grit emery cloth and a light oil to remove any preservative coatings and make a tiny adjustment to size.

I have done business with Reid Supply for years and like them and their merchandise and service very much. And as you can see, while the shaft are very affordable in price, ordering them through the online system has them being shipped UPS ground and that really runs the cost up on a small order. But if you phone the order in to their toll free number the ladies that take you order will set you up for a mail shipment for a small order like a few shafts.

The lengths of the drill blanks has been such for me so far that they are are little longer than needed for the longest needs, in some cases you can get two shafts out of one blank.

But it is wonderful to have the bits and pieces of cutoff on hand as they are good use in pushing larger shafts through when are flush with the end of the magnet housings.

The 3mm shafts found in old CD and DVD drives are still perfectly sized and usually free for use in motors with 3mm shafts.

Jack

Hey thanks for the write-up! Took apart an old CD drive and by golly, there's the 3mm shaft . Ought to get this broken motor back in action now.