Thread Tools
Apr 24, 2001, 09:41 AM
Registered User
Thread OP

Hacker for Hornet - pinions


Finally got my B20 for the Hornet, along with 3 very promising pinion gear contenders. Only problem is, the pinion holes are slightly too small for the motor shaft (just a hair). I'm trying to use some WES_tek reamers to enlarge things a bit but it is slow going. Anyone have any advice on how to do this quickly and accurately?

Thanks,

Loren
Sign up now
to remove ads between posts
Apr 24, 2001, 11:12 AM
Registered User
Steve McBride's Avatar
Loren,

I believe the difference in pinion hole and shaft diameter is about .3mm (280/300 shaft = 2.0mm). I recall somewhere on here about heating the pinion and getting a good fit. The heat will expand the pinion and allow the shaft to slide in. When it cools it shrinks and is retained by friction. Not sure if you can gain .3mm from this but perhaps worth a try? I would heat the pinion very slowly and be sure to support the back of the Hacker shaft when pressing it on.

Good luck!

Steve
Apr 24, 2001, 11:21 AM
Registered User
Thread OP
Ooops- forgot to mention these are metal pinions...
Apr 24, 2001, 11:31 AM
Registered User
Steve McBride's Avatar
Yes - metal pinions are what I was assuming. We used to fit large stainless steel berring races into housings by heating the housing in an oven at about 400 deg. F. and cooling the race with dry ice. The race would slide into the housing with just a tap and when it was all at room temperature, you could not seperate the two.

Use a propane torch to gently heat the pinion and slide the shaft into it. Have some way to support the shaft of the motor so when you press, you are only pressing on the motor shaft and not the motor housing.

If that does not work or you have your reservations, call a machine shop. Kirk at New Creations R/C may help.

Have a good one!

Steve
Apr 24, 2001, 03:04 PM
Registered User
Thread OP
Thanks for the advice Steve. I had no idea you could do that with metal pinions! This opens up many possibilities...

DO you think I could do it with a soldering iron? I am just a wee bit apprehensive about using a blowtorch, but if that's what it takes then I can definitely go out and buy one.
Apr 25, 2001, 12:04 AM
Registered User
G. Zod,

What tooth pinions are you trying? Where did you get metal ones? Let me know how your setup is working if you can. I'm still waiting for my B20 and shulze controller for my Hornet. Not having too much luck finding good pinions though.
Apr 25, 2001, 09:33 AM
Registered User
Thread OP
I ordered some 3/32 shaft size pinions from NPChobbies. they are meant for slot cars but are the perfect size (pitch, # of teeth) for the hornet. I also have a metal gear set for some Hitec servos, according to the hacker crew these are the way to go. I bought a blowtorch last night and will soon try to attach a pinion to the motor (the holes are slightly too small) so will let you know how that goes.
Apr 25, 2001, 10:06 AM
Registered User
Steve McBride's Avatar
Actually 3/32" equates to 2.38125 millimeters so if the pinions are designed for a press fit, the heating method should work (the hacker is 2.3mm shaft diameter).

Make sure you heat slowly - I would do it this way:

Collect the following:
- propane or butane torch
- fine needle nose pliers
- motor
- pinion
- thin masking tape, pinstriping tape, or similar
- Metal rod of 2.3mm diameter or smaller
- small machinists hammer

Mount the motor and use the pinion to decide how far onto the shaft it needs to be. Mark with the tape or a marker. Holding the pinion with pliers, heat it slowly in with the torch. You don't want it glowing red, just hot.
Quickly place the pinion onto a wooden table (metal will remove too much heat from the pinion) and place the motor shaft against the pinion. Using a wire the same diameter as the shaft as a punch. gently tap the rear of the motor shaft to press it into the pinion to the mark made in step 1.

Let us know how the Hacker works. I am very interested in your results!

Steve

Apr 25, 2001, 10:25 AM
Registered User
Thread OP
I'm confused as to what exactly gets punched and what the 2.3mm wire is used for (I'm thinking I probably won't be able to find something in these dimensions). I had envisioned heating the pinion, placing it on my workbench, and then jamming the motor, shaft first, right into the pinion.

My ham-fisted technique is widely renowned for generating immediate, irreversible, and often unintended results.
Apr 25, 2001, 10:39 AM
Registered User
Steve McBride's Avatar
I'm sorry - I confune a lot of people And it's my job to write procedures and work instructions....LOL

The wire is simply used as a punch. You don't want to put a lot of force on the motor so the wire is placed on the rearend of the motor shaft and the hammer used to tap the shaft into the pinion. Really any stiff wire, blunt nail, etc. can be used to accomplish this task. I would not put a lot of force on the motor case itself to press the shaft into the pinion.
Make any more sense?

Have a good one!

Steve
Apr 25, 2001, 10:49 AM
Registered User
Thread OP
Ah yes. Now it all makes sense...

Will let you know how I get on. Right now I'm trying to set my Hornet up for collective mechanics, but the brushless will be the next step in the equation.
Apr 25, 2001, 03:55 PM
Registered User
kasra's Avatar
Loren, You gave up on using the AF 010 in the Hornet? Brian had good results with his. I am putting one in the Hornet.
Latest blog entry: Car Show
Apr 25, 2001, 04:29 PM
Registered User
Thread OP
No, I just think the Hacker looks more promising, if you go by their claims of 15-16 minute flight times. It was also cheaper (they offered me a great Jeti06-Hacker B20 combo deal for $120) than the mighty micro, and I like the Hacker's snazzy purple motor can...
Apr 26, 2001, 09:35 AM
Registered User
Thread OP
The "take a blowtorch to the pinion" method didn't work. I tried this numerous times last night and the only thing I got out of it, I think, is a potentially damaged motor. Maybe the shaft hole was too small but I couldn't get that motor shaft more than 2mm into the pinion, after many cycles of heating, hammering, and re-heating. Maybe I will try to track down somw 2.6mm drillbits instead, but man these pinion gears are tough...
Apr 26, 2001, 09:51 AM
Registered User
Steve McBride's Avatar
I apologize if this method did not work. It is a tricky proposition at best.

Perhaps there is another source for pinions designed for 2.3mm shaft with a setscrew?

Let us know how it goes. If you dammaged your motor, let me know as I feel somewhat responsible. If you decide to give up on the Hacker let me know and I will purchase it from you.

Steve


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Metal Pinion for Hacker B22-20s for Hornet Arthur Knowles Electric Heli Talk 0 Jun 21, 2002 12:08 AM