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New builder from Gladstone Qld
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chunkulator



Joined: 27 Jul 2016
Posts: 211


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You can usually find bearings pretty easily on from local suppliers if you want to look for bearings with same ID but more convenient OD.

Post Thu Dec 22, 2016 11:50 am 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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Actually, Nick might be onto something. I am making my motor mounts out of nylon, and I do have some spare. I could melt the bearing into an undersized hole. The bearing holes as standard are into metal, the chassis of the mower, and this was what I was going to replicate. It would also make removal of the entire weapon, if needed, much easier.

Post Thu Dec 22, 2016 12:27 pm 
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DumHed
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Joined: 29 Jun 2004
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Location: Sydney


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I've had surprising success using a step drill to make bearing holes Smile


http://www.ebay.com.au/itm/322132126148

http://www.ebay.com.au/itm/322132238113
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Post Thu Dec 22, 2016 1:35 pm 
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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Another type of drill that is great for large holes in plastic is a Forstner bit. With low speed, it will cut deep holes with a surprisingly smooth side.



The unique feature of these bits is that they drill an almost flat bottomed holes so you can make bearing pockets if the material is thick enough
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Post Thu Dec 22, 2016 2:49 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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Ohhhhh, I might be able to break out the welder tomorrow.

A bit of luck today. Lying down the back shed was a couple of derelict chinese pit bikes. Pulled one out today, to have a bit of a squiz to see if anything might be useful for the build. Specifically, the weapon drive. Still wanting to go with a chain drive of some sort, I discovered that both the final drive chain and the intermediate drive chain, and sprockets, are the same pitch.

I also found that the shaft in one of the sprockets is the exact same diameter as my weapon shaft. All I had to do is make an adaptor for the other sprocket to the electric motor for the drive. That job was easy, bit of grinding, drilling, and tapping of threads sees an adaptor made with twin grub screws to suit the motor shaft Just have to weld the sprocket to the adaptor tomorrow.

Post Thu Dec 22, 2016 6:58 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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Drive motor mounts. They still have to be cut horizontally and have about 5mm taken from the middle to give sufficient clamping force. They will also be glued to the mounts.

Post Fri Dec 23, 2016 8:07 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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One possible mounting method for the weapon drive motor. I do have a couple of other ideas as alternatives. They have only been roughly cut, and will have to be shaped to suit the motors profile.

Post Fri Dec 23, 2016 8:10 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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A rough layout. Approx 350mm from front to rear.

Post Fri Dec 23, 2016 8:14 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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The bearing mount for the weapon also acts as a chain guide.

Post Fri Dec 23, 2016 8:17 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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As suggested previously, I used a stepped drill, then a hole saw to make a hole just undersize for the bearing, then pressed the bearings into the holes. These are the weapon mounts.

Post Fri Dec 23, 2016 8:19 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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The weapon drive. Sprockets welded to home made adaptors to suit both the drive motor and weapon shaft.

It turns out that this length chain, that I was working with, left about 5mm space between weapon blades and drive motor body, so I have had to scrounge longer chain, which allows me to mount it any distance from the weapon. Ideally, I am looking for about 15mm, to keep the chain as short as possible, but allow enough room for some plating between weapon and motor.

Post Fri Dec 23, 2016 8:23 pm 
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Nick
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Joined: 16 Jun 2004
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That's some quick progress! With the drill motor mounts, you need to support them at the front; the join between the motor and the gearbox is weak due to the thin metal of the motor case and while its good to have a mount where yours is, its not strong enough by itself.
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Post Fri Dec 23, 2016 8:28 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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Yeah, the motors are only sitting in there for the photos. Its already mentioned on Facebook about supporting the gearbox area as well. Still a work in progress. But its got to be on hold for now. Work beckons over the next couple of days. Not to impressed about a 1400 shift on Christmas day.

Post Fri Dec 23, 2016 8:34 pm 
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Bundyrumandcoke



Joined: 01 Dec 2016
Posts: 31
Location: Gladstone Qld


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Motor mounts gearbox end. It will also give me an alternative way to mount the motors.



And the weapon motor mount a bit more refined.

Post Mon Dec 26, 2016 8:53 pm 
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miles&Jules
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Joined: 19 May 2010
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Location: ipswich QLD


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Good to see progress- whats the blue stuff your using for your mounts?
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Post Mon Dec 26, 2016 10:20 pm 
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