AR15.Com Archives
 Dremel hot-rodding / where to get better-quality bearings?
Floppy_833  [Team Member]
10/4/2010 1:24:20 PM
I have a Dremel 400 xpr that gets quite hot around the bearings when run at high speed. The 400 is officially discontinued, though there are still a few NIB out there to be had. The new model is the 4000, but I have an accessory that will not fit on the newer model-4000. Otherwise mine is fine, so I am wondering about putting better bearings on the one I got. I haven't opened mine to check the bearing size, but other accounts online say that Dremel uses non-flanged 626Z's, which are 6 x 19 x 6mm.

The bearings are press-fit onto the armature assembly of the motor, so you need the right equipment to get the old ones off and the new ones on. I have them, and can do that. The problem is I cannot find anywhere to get higher-quality bearings.

I know of places like Bocabearing, VXB and eBay. If they give any ABEC rating, it is usually ABEC-1. I recently bought some skate bearings for a project, and they were available in ABEC-5, 7 and 9, and the 9's did cost more than the 5's did, but even so the 9's were still only ~$1.25 each (for 6 x 22 x 6mm's). So I know there must be better grades out there, and they don't cost much.

Skateboard and skating websites say there's not much benefit to getting the higher ABEC ratings. A skateboard wheel rolling at 30 mph is only turning about 4500 RPMs though, and a Dremel will spin at 25,000 to 35,000 RPMs at full-tilt. I would think that there would be a benefit to using tighter-tolerance bearings, given the propensity of the Dremel bits to chatter. Bocabearing and VXB even sell full-ceramic bearings, but they are still only ABEC-1's.

Does anybody know anywhere to buy higher-quality bearings?
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Fat_McNasty  [Team Member]
10/4/2010 1:29:42 PM
how about here?
Fat_McNasty  [Team Member]
10/4/2010 1:30:15 PM
Originally Posted By Fat_McNasty:
how about here?


the ceramic ones..
Floppy_833  [Team Member]
10/4/2010 1:52:24 PM
Update: the model number is really just "626", the Z is apparently a fit suffix itself.

Originally Posted By Fat_McNasty:
Originally Posted By Fat_McNasty:
how about here?


the ceramic ones..


I did look there before. Boca, VXB and eBay is where I look for bearings first.

Surprisingly enough, the full-ceramics Boca sells are either only ABEC-1 or ABEC-3. ???

All the skateboard websites like to tell you that "the ABEC rating doesn't matter" and insist it's just a useless rating unscrupulous retailers use to overcharge you for crappy products, but those same websites fail to explain how a bearing could be made very well, and still garner a lousy ABEC rating.... (ummm,,,,,, who is selling crappy products again?... ;) )

Searching for the real model number, Bocabearing does have a ABEC-7 hybrid for $16 each, out of stock at the moment. That would be better than all-steel I suppose.
http://www.bocabearings.com/bearing-inventory/Radial-Bearings/18200/SMR626C2OS7NB2-6x19x6
I also found a couple places with hybrid ABEC-5's, for similar ~$15 prices.

I'd still like to find some full-ceramic ABEC-9's though. :|
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edb66  [Member]
10/4/2010 1:57:02 PM
Whats the attachment that wont fit? If it's the planer for instance, I took the Dremel and ground off the two flanges and it works fine on my 4000.
DzlBenz  [Team Member]
10/4/2010 2:07:10 PM

Originally Posted By Floppy_833:


All the skateboard websites like to tell you that "the ABEC rating doesn't matter"

<snip>
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For a skateboard, that's probably true. For a 30-50K RPM motor shaft ... not so much.

Fat_McNasty  [Team Member]
10/4/2010 2:11:23 PM
Originally Posted By DzlBenz:

Originally Posted By Floppy_833:


All the skateboard websites like to tell you that "the ABEC rating doesn't matter"

<snip>
~
For a skateboard, that's probably true. For a 30-50K RPM motor shaft ... not so much.



yup and Boca comes back as one of the must have's for RC heli's.. Call them and ask, I know of a few guys that needed specal use items and they made it for them.. and it wasnt too much more then the stock unit..
DriftPunch  [Team Member]
10/4/2010 2:17:17 PM
You are just flat out hard core if you are looking to swap bearings on a Dremmel...
MajorStumpDemon  [Member]
10/4/2010 2:18:40 PM
Originally Posted By DriftPunch:
You are just flat out hard core if you are looking to swap bearings on a Dremmel...


its a race dremel obviosly
DzlBenz  [Team Member]
10/4/2010 2:19:53 PM

Originally Posted By DriftPunch:
You are just flat out hard core if you are looking to swap bearings on a Dremmel...

He's got a lot of barrels to flute.
DontShootMyDog  [Member]
10/4/2010 2:20:45 PM
Originally Posted By DriftPunch:
You are just flat out hard core if you are looking to swap bearings on a Dremmel...


And have special tools to do it!

44-40pro  [Member]
10/4/2010 3:33:55 PM
Check into Foredom Brand hand drills. I have one that is 40 yrs old from my jeweler days that still runs like new. Might be worth it to you if you use them alot/day. Brownells ahs them iirc. Not cheap, but all metal, and worth every penny. 44
Floppy_833  [Team Member]
10/4/2010 6:32:43 PM
Originally Posted By edb66:
Whats the attachment that wont fit? If it's the planer for instance, I took the Dremel and ground off the two flanges and it works fine on my 4000.

The attachment is the plunge router. One I had broke some time ago, but I will need to buy another as I need it again.

Originally Posted By 44-40pro:
Check into Foredom Brand hand drills. I have one that is 40 yrs old from my jeweler days that still runs like new. Might be worth it to you if you use them alot/day. Brownells ahs them iirc. Not cheap, but all metal, and worth every penny. 44

I know about Foredoms, though I don't have one.
They are built great––but even so, they are all corded tools, and the cord means they require a special work-area setup (with an elevated hook to hold the motor, so the flex-cable doesn't interfere with using the hand-piece). I don't have a permanent work area I can use like that....
Also they are expensive; a fair setup is going to be $400-$450 or so. I will try using a Dremel for things I'd probably never risk a Foredom on.
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edb66  [Member]
10/5/2010 1:12:12 AM
Sent an IM Floppy.
Floppy_833  [Team Member]
10/5/2010 6:01:43 AM
I got the IM.
That the plunge router does fit on the newer model 4000 is good news, but my 400 still isn't dead yet––even with stock bearings.

This may take a day or two...... I emailed Dremel asking what grade the factory parts are. I'm gonna laugh if they're ABEC-1's.
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LowBeta  [Team Member]
10/5/2010 6:27:16 AM
Originally Posted By MajorStumpDemon:
Originally Posted By DriftPunch:
You are just flat out hard core if you are looking to swap bearings on a Dremmel...


its a race dremel obviosly



High speed shaft! low drag bearings!
pv74  [Team Member]
10/5/2010 6:28:24 AM
Motion Industries? They are a good bearing suply house.

http://www.motionindustries.com/motion3/jsp/mii/index.html
Floppy_833  [Team Member]
10/6/2010 11:59:48 AM
Originally Posted By pv74:
Motion Industries? They are a good bearing suply house.

http://www.motionindustries.com/motion3/jsp/mii/index.html

I searched there for "bearing 626" and all I got relevant was a few cro-mo's for ~$15. So far the hybrid ABEC-5's are looking like the best choice.

Dremel responded, but they weren't a lot of help.
They said the bearings weren't available from them separately (I already knew that), that they sold new armatures complete (knew that too) and that the bearing specs they used was proprietary info and they wouldn't give that out.



So I opened up the tool and looked myself; the bearings are marked "NMB", "626DSD28" and "SINGAPORE".... That part number doesn't match any of the manufacturer's current listed products, so I emailed them to see if they'll spill the beans.

The bearings in the tool appear to be solid and turn smoothly––but are still rather stiff to turn, even with the armature removed from the field assembly and both shields of one bearing removed.

––––––

By the by, I will need to cut acetal, and the Dremel router bits have no twist so I don't think they're gonna do well.
I know about PMT already but is there anywhere else that sells tiny mill bits with 1/8" shanks?
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Floppy_833  [Team Member]
10/16/2010 2:22:41 PM
I did get the bearings changed, by the by.
I am now offering expert fluting service––not only firearm barrels, but car brake lines and home water pipes as well.

Summary:
It requires a lathe, a milling machine and an arbor press, among other smaller bits of stuff.
The results are mixed; a slightly-faster low-end RPM and a slightly-slower high-end RPM.
I made a couple errors and fudged it up a bit. It is still fully functional, but didn't turn out perfect. I could do the second one perfect.

I started a thread in the DIY & Hobbies forum on Something Awful about it, if you care: http://forums.somethingawful.com/showthread.php?threadid=3357364
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