We can get it in almost any state we like. Annealed, and pre hardened at various levels... I think.

I managed to find this sheet that compared loads of different types of tool steels. After sitting down for a while I realised that wear resistance isn't actually what you want on a single tooth weapon... it was hardness and impact strength. Drums might need wear resistance since they buzz against opponents a lot of the time but for a whisk or disc... you wanted to resist and absorb single, heavy hits.

i hope that logic is right too.

Motor show

I couldn't get motivated to set up the rotary table tonight and finish off Jolt's motor mount, so here is a review of the motors from my vertical spinners:



Front left is the original motor from Mr Mangle, a Neu 1910 in-runner: 680 KV, 1.2KW cont, 2.4KW Max. The custom front end has dual bearings. The power rating and lower KV just isn't enough to spin up the beater without getting over heated. Other than that, it is a very solid motor that will probably be used as a backup.

Front right is the new motor from Mr Mangle, a Hacker A50 Turnado out-runner: 850 KV, 1.5KW cont, 3KW max. The motor mount has a needle roller bearing to support the 8mm shaft, which is definitely needed after a ball bearing disintegrated at the last event. although the power rating is only a little higher than the Neu 1910, the extra cooling from the built-in fan helps this motor spin Mr Mangle's beater up to a dangerous speed without getting too hot. It still needs a custom rear end-bell.

At the back left is the motor for Shiny (also known as Mr Mangle V2). It is a Neu 2210/24: 860KV, 2KW cont, 4KW max. The custom front end has dual bearings and large air vents. With an extra 1,000 watts of peak power over Mr Mangle's motors, the only question is whether the beater will explode on the first impact!

At the back right is Jolt's Kontronik Pyro 800 out-runner: 400KV, 5KW cont, 10KW max. The motor will be upgraded with a 10mm shaft and a front needle roller bearing in the next couple of days. After that, it may get squeezed into Mr Mangle for a spin-up test.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Nice, its a bit of a choose your weapon situation
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Man cave:

The excavation company has been slow to level the new shed site - something that should have taken 1 day has stretched out to five and they haven't started grinding out the giant tree stump at the back of the site:



Worst of all, they took the keys to the diggers so I can't have any fun over the weekend!
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Jolt:

Jolt had some major design upgrades today:

* Rear offensive wedge with full width bracing bar to take on other spinners.

* Batteries now 5AH, 65C capable of over 300 amps continuous.

* Beater now 36mm thick, weighs almost 5Kg.

* Front forks increased in size.

Here is a side profile diagram:



I really hate rear wedges; they take up so much space and weight, with 'dead air' under them that can't easily be used to locate internal parts. In this case, Jolt had over 4Kg of spare weight so adding the wedge made sense and only added 2Kg. Having a passive backup weapon is a good option in a competition dominated by many other powerful spinners.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Theoretical weapon speed? Weapon dimensions? And how thick is the rear wedge? Don't tell me its like 1" thick titanium!

I strongly suspect it will be 20mm titanium
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

The side and rear armour is 12.7 mm (1/2") plate. At the front corners it is doubled up with the replaceable forks to 25.4mm and the rear wedge gives a horizontal cross-section of 16mm. Spinners hitting around the reinforcing bar height on the wedge will come up against a 37mm horizontal cross-section - better than many heavyweights. The wedge is at 37 degrees, the perfect offensive angle to launch other spinners according to the Riobotz manual.

The weapon motor's 400KV rating should produce a no-load speed of 17,600 RPM from 44 volts. I plan on a 2:1 reduction to start with, so anything over 6,000 RPM at the weapon would be satisfactory. If the motor isn't straining, then the ratio can always be reduced for more speed.

The beater has a 160mm diameter and a theoretical weight of 4.85 Kg at the moment. The dimensions and weight can be increased a bit to use up any spare weight.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Jolt:

The motor mount is all finished and ready to spin up:



I decided to leave the marks from the roughing cutter on the top of the mount as they match the grooves on the motor can and make a nice contrast to the smooth surfaces on the rest of the mount. Also, it was one less tool change

The final weight including the mount is 645 grams - compared to the Mag motor in Scissorhands, that's 63% less weight and is has 4.5 time the power (assuming we are comparing hobby watts with hobby watts). That's going to give Jolt a major advantage over some old-school US bots with brushed motors.

This has gotten me thinking about using the same motor in Scissorhands. A 2:1 belt reduction from the motor to the gearbox and then a further 2:1 reduction in the gearbox will give a 4,400 RPM no-load speed, which is much higher than what the Mag motor achieves.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Machinist's assistant and swarf brush

There was a surprise when I started setting up to make a new pulley for Mr Mangle:





I can't imaging why a possum would want to sleep behind an oily lathe, perhaps its cooler back there. I tried luring him out with slices of banana but he wasn't having any of it. After devouring my bribe, he just went back to sleep in the same spot! I guess the pulley is on hold until later tonight.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Nick, have you got any advice on buying a good rouging cutter. I am getting a tad suspicious at some of the price differences and heavy discounts I keep seeing.

Like here they lop off over 70%: http://www.engineeringsupplies.co.uk/10mm-fine-pitch-sabre-coated-ripperroughing-mill-p-2032.html

And the same here: http://www.engineeringsupplies.co.uk/10mm-long-flute-roughing-tialn-coated-carbide-cutter-p-1986.html

(Both of those are 10mm, 4 flute roughing cutters, on has a basic coating, the other a carbide coating)

Ebay isn't much better, you either pay a bomb or a fraction of the cost.

EDIT: It will mainly be used on HDPE, Aluminium and Steel.. so I will probably need 2 types of cutter. One for the softer HDPE and Alu and one for the Steel.

Nick that possum knows the lathe is to heavy to move so he won't be disturbed …and maybe he is deaf so doesn't mind the noise. ..ps those motor mounts look sick.
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Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Ahhh his ears are all floppy *cute overload*

Those prices seem reasonable to me for a carbide end mill. I've been buying them surplus from $10 aud a piece typically. His Ebay is ToolingStation if you want to have a look. Perhaps you have something similar there?

May be better off just using a standard HSS slot drill (2 flute) for plastic work. They seem to leave much less of a burr on the part. Even in a dodgy little hobby mill it will plow into a chunk of plastic to full depth without much worry so the need for a roughing cutter seems a bit excessive!

Have been keen to give a router bit a try though I hear they work quite well on plastics in the mill
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

We have a Sieg SX3 Mill, so we will be able to do steel if we wanted but until now we haven't needed to.
And you do mean the prices are reasonable before or after the 70% discount?

I will check out that ebay store to! Thanks!

Its hard to compare end mill prices; there are so many variations of coating, metal type, tolerances, etc that two similar looking cutters could have wildly different performances and cost.

Both of those cutters look 'high-end', with powered steel or carbide construction. Although they are small, I'd say the discount price is reasonable but they are probably wasted on a smaller manual mill. They look to be aimed at commercial CNC applications where bleeding edge performance equals more profit.

I only use carbide cutters when I need to mill titanium, otherwise I go for cobalt steel of just HSS at much lower cost and they last a long time in aluminium. One issue with carbide is that while its very hard and the cutting surfaces stay sharp, its also brittle and doesn't like shock - they can snap unexpectedly.

Both those cutters you linked to are aimed at steel; for soft & stringy materials, you want a coarse pitch, a higher helix angle (36 deg. is common) and fewer, larger flutes to clear the swarf quicker. Like Glen mentioned, a two flute slot cutter will do a pretty good job in plastic, where the large flutes help the chips to exit the cut. Roughing cutters tend to make little chips like snowflakes, which can be handy on deep cuts where the chips can build up and cause problems.

If you want to cut a variety of materials, with just one rougher, I would go for the fine pitched ones like you linked to; they will work in softer materials as long as you let the chips clear out, while a coarse pitched cutter will wear out in steel faster.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion