74041 Tamiya electric handy drill

[GregM]

A friend of mine has a Tamiya electric handy drill. Since her machine seems to be worn after years of use, I suggested her to see if there is anything repairable inside. It once came as a kit, so it should be easy to open up for repairs. If the motor's brushes are worn down, does anybody know a suitable replacement? Or is there a manual with the machine's specs or assembly guide available for download? Unfortunately TamiyaUSA.com doesn't provide a manual on their servers, and for contacting them you need to be a US resident.

I would be very thankful for help.

[Nobbi1977]

Try this

http://www.model-making.eu/products/Electric-Handy-Router.html

Looks like the same motor they put in the 1:32 4x4 kits

[Yonez]

So, can you put a tuned mini4wd motor in it then?

The mind boggles...

[GregM]

Thank you very much. The 74042 Electric handy router uses a different gearing (high RPM versus the high torque gearing of the 74041 handy drill), but I guess their motors could be indeed the same.

"1:32 4x4" sounds like Tamiya Mini4WD, if I recall right.

EDIT: From looking at the 74042 manual, I can see a plastic 1150 bearing. Time for hop up ball bearings!

[Mokei Kagaku]

Both the 74041 Electric Handy Drill and 74042 Electric Handy Router use the regular FA-130 motor in the 3V version, so if a motor can't easily be sourced separately, practically any Mini 4WD with a "single shaft" motor or many of the Tamiya Educational kits with 3V motors can serve as parts sources.

74041 and 74042 are very similar, with the main difference being the different gear ratios. For improved durability, the front plastic bearing can be replaced with an 1150 ball bearing. I've done that on my router and drill and have used them a lot, and I'm surprised to hear that your friend has managed to wear it out!

They may both look a bit toyish, but the quality is of the expected Tamiya standard and due to their light weight and compact design, they are great for delicate tasks where normal mini drills like for instance Dremel are simply too big and clumsy to use. Highly recommended!

I reckon the manual Nobbi has linked to for the Router is enough as the Drill is pretty similar, but in case you should need the manuals, I have them and will gladly scan them for you.

[GregM]

Thank you so much! I managed to find scans of the 74041 manual on a greek website:

http://www.e-kalfakis.gr/στατικα-μοντελα-εργαλεια-ειδικα-εργαλεια-tamiya-74041,-electric-handy-drill-p-3328.html?language=en

For the sake of convenience, I've reuploaded it for embedding here:

EDIT: So if you say FA-130 in 3V version, could this e.g. mean the Mabuchi FA-130RA-18100?

http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=fa_130ra

[GregM]

Mokei, the more I read about the Handy electric drill from your post and reviews on the web, the clearer it becomes that one of these machines could be very handy for some of my modelling tasks. Thus, I've told my better half about my thoughts, let's see if there might be any surprise for Christmas. I find it quite charming that the drill comes as kit.

By the way, I just found a domestic supplier for the F130-RA-18100:

http://robotik-teile.de/Tamiya-980112M-Mabuchi-FA-130-Motor

[GregM]

I eventually got the Tamiya drill as a Christmas gift.

Of course I couldn't hesitate replacing the plastic bushing with a ball bearing of the same size. But one thing puzzles me:

The drill doesn't run true. It feels like there's quite a bit of slop where the bearing holds the drill shaft. I compared this to my Dremel 300, which runs perfectly true without any slop,

It doesn't make a difference if I use the supplied plastic bushing or the ball bearing. The shaft itself seems to be fine and straight, but as soon as there's a drill bit attached to it, it begins to jiggle when in use.

I wonder if this applies to all these Tamiya battery operated drills. Is there any way I can reduce the slop?

[bromvw]

I eventually got the Tamiya drill as a Christmas gift.

Of course I couldn't hesitate replacing the plastic bushing with a ball bearing of the same size. But one thing puzzles me:

The drill doesn't run true. It feels like there's quite a bit of slop where the bearing holds the drill shaft. I compared this to my Dremel 300, which runs perfectly true without any slop,

It doesn't make a difference if I use the supplied plastic bushing or the ball bearing. The shaft itself seems to be fine and straight, but as soon as there's a drill bit attached to it, it begins to jiggle when in use.

I wonder if this applies to all these Tamiya battery operated drills. Is there any way I can reduce the slop?

does the chuck tighten up true without a bit in it Greg ? Any remote chance its cross threaded ?

[Mokei Kagaku]

I wonder if this applies to all these Tamiya battery operated drills. Is there any way I can reduce the slop?

Strange!

I've had both the 74041 Electric Handy Drill and the 74042 Electric Handy Router for around 8-9 years by now and have used them a lot and haven't experienced this problem at all. (I too replaced the plastic bushings with a ball bearing from the very start.)

[GregM]

When I just screw the clamping nut on, everything seems to be fine. But as soon as the collet chuck comes into play (both the fine as well as the large bore chuck), it runs untrue.

Edit: I have a guess. Either the nut could guide the chuck off-center. Or the mainshaft could misalign the chuck where the chuck touches the flat bottom area of the mainshaft bore.

I'll have another look at the drill tonight.

[GregM]

Nope. As long as the clamping nut is only screwed in halfway (without a collet chuck inside), it is still centered well. But once it is tightened down on the shaft, I can see the clamping nut running untrue.

[bromvw]

Nope. As long as the collet is only screwed in halfway (without a chuck inside), it is still centered well. But once it is tightened down on the shaft, I can see the collet running untrue.

i think i would complain in that case and ask for a replacement

[GregM]

I certainly would, but I think it's too late for that, and AFAIK my better half ordered the drill from Japan for me last year. I'll meet up with some other modelkit hobbyists this weekend, some of them use the same drill. So I could see how theirs are working and compare them to mine.

I'll let you guys know if I will be in the need for a spare shaft or collet chuck.

[GregM]

So, I tested another drill, and it had near zero slop at the mainshaft. Changing out the clamping nut didn't made a difference for my drill.

Tonight I'll see if I can get the ball bearing to sit tighter in the plastic case, as well as using heat shrink to make the shaft fit better into the ball bearing.

[bromvw]

Got any calipers Greg - i wonder if the shaft is worn / or the bearing is knackered . ?

[GregM]

So I tried several things like bearings from different suppliers as well as narrowing the tolerances along the mainshafts mounting points. None of them helped.

I then mounted the Tamiya shaft on my power drill along with a drill bit. It looks like either the shaft might be bent from the start, or the external thread on the shaft has been cut wrong.

If anybody has a spare shaft left, I would be interested.

[GregM]

So just to satisfy my curiosity, I tried hardened steel 3-slot collet chucks along with the corresponding steel clamping nut out of a Proxxon Micromot 50/E yesterday on the Tamiya drill.

Proxxon spare part no. 28940

Looks like the wobble problem is solved now. Seems like the Tamiya clamping nut and collet chucks on my Tamiya drill were just badly manufactured, but I don't trust the weak aluminium (?) 4-slot chucks no more anyway. I'll post pics of the fit to the drill tonight.

[Nobbi1977]

I love my little drill

 

[GregM]

Tamiya electric handy drill with stock clamping nut, stock 2.0 mm collet and the supplied 2.0 mm HSS drill bit. The 2.0 mm collet runs slightly untrue, but OK.

Drill with Proxxon clamping nut, 3.2 mm Proxxon collet and a 3.2 mm Proxxon HSS drill bit. Runs true. I tried all available sizes. 2.0 mm was still very good. 1.5 was bearable, 1.0 was bad.

This is strange, since all the collets will work very good when in use with the Proxxon Micromot 50/E drilling/milling machine.

Drill with 2.4 mm collet and a 0.6 mm TiN coated drill bit. Shaft diameter is uniformly 2.35 mm for the TiN bits of this bit set (RoNa #812154). Runs perfectly true for all sizes in the 2.4 mm collet.

So I'd recommend going for a drill bit set with uniform diameters, which also makes changing drill bits a breeze.

[Crash Cramer]

Mmmm, I might have to investigate buying one of these little "toy" drills as I have called them before I read all this.