chris -

jeff got them from some chinese company called shenzen nernst. but he only ordered samples. if you want to buy more you have to order in bulk,

and i tried to order more samples but i think theyve picked up on it

I find a lot of chineese places hard to deal with. I found a company with a website in english who sold bearings but didnt list the price so I sent them an e-mail asking for prices in AU dollars and I got back a 20 page thing of chinese with 2 lines at the bottom in english saying "we dont deal to the australian public"
c'ya from Chris
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Mr "squirt"
Team Blazing Star

I dont think many chinese companies believe that a country can exist with only ~20 million people in the whole place..

Soemone in the Charger Club (as in Valiant Charger) once enquired about getting some reproduction weber carburettors made by the factory in Italy, only to be told that Australia represents such a tiny part of Webers sales, that our entire national *yearly* usage quantity of weber carburettors was made by the factory on *1* morning of the year, before morning tea time.

We as a country are probably barely worth their time, much less dealing with individuals.. When you sell something like drills *retail* for $10-$20, if you spend more than 30 seconds on the paperwork for the sale, you've probably lost money.

Well i am currently living in china & beleive everything that is said & more. Very self centered & VERY hard to change their thinking. They work incredably hard, however they can not think outside the box. One of my empolyees was doing a repetitive task, & he was doing it wrong, when asked about it, his reply: "thats the way we always do it in china"

Can you give me the contact details about those batteries & I will see if I can get my company to get a few samples. It is always much easier for a chinese company to deal with another chinese company.

Is there any thing else i can source for you guys over here? batteries, motors, gearboxes?? I am returning home at the end of July after my contract expires, so I will be primed to start building a tracked bot.

That's VERY interesting! Will you be leaving any useful contact people behind? When I worked in a PC retail shop, it was super useful that the boss had family 'back home' to ship parts and negotiate with factories.

I would say that batteries would be the #1 thing to organise. there are the cheapo Nicads that go into drills, but also some really good NiMH ones like the GP3300 [url]http://www.gpbatteries.com.hk/html/products/rechargeable_hydride.html [/url]and probably many more.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Well I am actually going to contract back to the company I work for now, just work from home in Oz. So my translator/personal assistant & secretary will still be working for me. Therefore I can get them to organise anything we need.

Lving in china (shanghai) is unbearable for someone that likes his space, peace & quiet & enjoy the outdoors. This place is a concrete jungle.

However if there is someone who is a good/great project manager, likes living in apartments & would enjoy a challenge there is a opportunity opening up here at the end of July. the money is good, the tax rate makes is better & an apartment is included. Let me know if you are interested.

Hey Guys been trawling the Forum with the search term/s "Andrew-Mod Gearbox" ect. which lead me here looking for info on this famous mod can anyone point me to a thread or wiki? cheers in advance Tim

AndrewMOD replacements HERE
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https://www.halfdonethings.com/

Slightly different but the dewut will out-power an Andrew mod no trouble.

Glen I am sure will remember more, I can only think of replacing the pins and grease. I think something was done with the plate as well.
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Remember to trust me, I am an Engineer.

http://www.youtube.com/watch?v=rp8hvyjZWHs

That's what I've read about replacing the pins with larger cut rod and drilling out the gear centers to suit, silver soldering the pins in..... they all sound like great ideas would like to see what's involved as I have a few spare boxes and making them stronger wouldn't hurt.

These are mostly urban myths, here is what I have learned from modding dozens of gearboxes:

* You absolutely need to use hardened dowel pins or hardened drill rod; anything else just wears or pulls out again.

* Silver soldering a properly pressed in pin does nothing except remove the temper from the steel. No solder will wick into a joint that is a tight press fit and will just make a relatively weak joint on the surface of the carrier plate. There have been reports that TIG welding the pins was even worse.

* Adding an extra carrier plate to the top of the pins (AKA the Andrew mod) does work but its difficult and time consuming.

* Drilling out the hardened gears needs a specialised carbide bit that leaves a precise and glass-smooth bore. Regular steel drills just won't cut the gears and some carbide drills will leave a rough & high friction surface.

Here are some tips that worked really well for me:

Use 5/32" hardened dowel pins; they are cheap and relatively easy to get on-line. alternatively, get hardened drill rod and cut your own pins to length. If you make your own pins, the end that gets pressed in needs to be chamfered so that it doesn't scrape metal off the carrier plate and enlarge the hole, which loosens the fit.

Drill the gears with a 4mm carbide straight flute drill. It cuts thru the hardened gears like butter and leaves a mirror smooth finish. The drills are expensive but I can drill out gears for just for the postage cost.

The pins need to be pressed into an undersized hole for a permanent fit. Drill out the pin holes to 9/64" and then ream them to 0.1557", which is a pretty tight press fit for the 5/32" pins. Dowel pins are tapered at each end, so you want to press the pin 1 or 2 mm thru the plate and then grind off the excess so that the pin makes 100% contact with the plate. I never had a pin pull out after this. The reamer costs around $15 to $30 on-line.

Its easy to make a jig to press the pin in with a drill press or a mill; they need to go in at exactly 90 degrees or either the gears will bind or the press fit will not be strong enough.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

we Tig welded ours,
instead of pulling out it just sheared off the pins.
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Mechanical engineers build weapons, civil engineers build targets

TIG welding is a no go. Even with a very good carbon catching rod to avoid a brittle weld, the pins just broke off.

Brazing-silver soldering had exactly the same result.

Loctite 638 had good results for repairs.

That Loctite 638 is amazing stuff - I remember your good advice every time I use it
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Thanks for all the info Nick that's what I'm looking for, surely if it has been done in the past, I could atleast have a crack at it. Drill motors have been good to me and they are relatively cheap (no post purchase shipping cost or wait time) and accessible.

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* Adding an extra carrier plate to the top of the pins (AKA the Andrew mod) does work but its difficult and time consuming.

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quote:

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The drills are expensive but I can drill out gears for just for the postage cost.

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