FW Spinner Advice please :-)

Hi guy. Just want a bit of advice pls.
Iv been on with building FW crusher for a while and iv been having allot of trouble with a few things and have put the idea of a crusher on hold for a while.
I wanted to make one because I find them really fun to watch, however another bot I find really fun to watch is Yetti from BB so going to base it on that I think.
I already have a prototype 4wd rambot made that whizzes around no problem. So it's the weapon system I need help with.


I want to use the V belt and pulley approach so it acts like a clutch system. But not really sure where to get the pulleys and belts from and what type because there seems to be loads. So thought I'd ask the experts here.
Also iv seen various people using different approach to bearings, bushes, fixed shaft etc etc.., any advice there or is it each to there own.?


Weapon drum/blades:
Currently I'm thinking about 100mm diameter.. maybe 150.
Because it's my first one I don't think I want to shell out for a full drum so may get 4 x 10mm thick hardox 500 discs cut and slam them together instead.


Weapon motor:
18v Makita circular saw motor. Anyone else got experience using one of these... it seems ruthless when I am using to cut through mild steel strut and stuff at work, so imagined it would make a good weapon motor.. and the brushless version is even more hardcore at 5000rpm. The standard brushed version I use is 3100. Think they are between 600 and 750w


Anyway a bit of advice would be appreciated.
Cheers
Matt

Kinda want someone to answer this because I'm having the same problem as Matt when it comes to sourcing V-belts and pulleys.

Please help us :)

I don't know a whole load about spinners so others will have to chime in here, but I know a lot of roboteers use beltingonline.com for pulleys, belts, gears and sprockets. As for bearings and bushings, I'm not very inexperienced in that area, but PP3D uses bearings and Aftershock uses phosphor bronze bushings, so it might be a matter of preference or simply a case-by-case thing.
Your circular saw motor, does it come out of the casing OK? That's the first thing you really need to consider when taking apart tools as sometimes the casing of the tool can form the casing of the motor, and then it becomes a bit difficult to rebuild the thing.

I'm assuming all the builders are busy with RW at the moment. I kinda steamboated ahead and bought some Bearings and a 25mm titanium shaft lol.

I haven't tried taking the saw appart yet no. May have a tinker over the next few days and see what happens lol.

What you've got sounds plenty substantial for a featherweight to me.

Attachment 6674
Well........ it's arrived :-)
Seems to work well on the bushings but Imagine it will need polishing to a shine to work best.
now to search for a pully and belts.

Before I buy 2 of these and a belt to go with..... are they suitable or not? Or is there better choices?
Attachment 6675

Also.... what methods of fixing the pully to the disk to people use? I'll be using a dead shaft and imagine just welding the pulley to the disk.

I used to get all my gears and pulleys and clutches from http://www.hpcgears.com/

belting online are a regular customer mentioned on here, also try

bearingboys - often have 20% discounts for email newsletter subscribers

simplybearings

Check ebay. There are dozens of pulleys etc available.

Adam I tend to find HPC are pricey compared to others and their quality recently can leave a lot to be desired.

If you are welding the pulley onto the disc then make sure it's bang on centered.

Thanks lads... that brings me to the next question.
How many grooves and how deep should I be looking for in my pulley system. I imagined 1 groove about 10mm deep but I really don't know. Maybe a thinner, wider belt with more grooves is the way.
And if I don't weld the pully to the disk, what other methods are there ?

Wouldn't bother with more than 1 as it will be more than enough for a featherweight. The other issue you might have with V belts is the size of the small pulley as they typically don't like to go around very small radii. I'd consider small timing belts as another option.

Bolts, keyways, clamping mechanisms are all potential methods to attach the pulley. The disadvantage with welding is that it's a nightmare to remove the pulley from the weapon if you have to.

Gone with a live shaft now because seems easyer for my first build.
Did a eBay search as you suggested Gary and found pretty much what I wanted, so cheers.
https://www.ebay.co.uk/itm/272371124524
just got to find a belt to suit.

Going to draw up a weapon assembley design later to post here to see if there is any issues with my idea.

Rite then. Had some time and have come up with this weapon assembley design.
please excuse the rather amateur drawing. I did try it on solid works but I don't know it well enough yet, so was taking far to long.
drawing is to exact scale.


Attachment 6679.

Live shaft Weapon key


Shaft is 25mm grade 2 titanium (which I already have)
Rest is as followed


A- 6mm bolts to keep retaining disc in place
B- 2mm thick 40mm diameter stainless steel retaining disc to make sure steel bushes don't come out of bulkhead
C- Bulkhead made from 25mm aluminium (I think)
D- HDPE washer/spacer
E- 25mm shaft collar (bottom half of it welded to disc)
F- Removable tooth (optional / not sure yet)
G- Disc 30mm thick, 200mm tooth to tooth diameter
H- 68mm v-pulley with hub. Mounted to shaft with 4 grub screws that also sink into shaft 2 or 3mm
I-25mm wrapped steel bushing / plain

Attachment 6680 Attachment 6681



So what's the verdict?? Completely rubbish or ok? lol

Can you extend the shaft through the supporting "forks" and then have it secured with something like a nut or something? As then any sideways forces will be taken by both sides of the forks rather than just one.

Possibly putting a bolt into the shaft at each end and having a washer stop the shaft from sliding into the fork.

Good idea spreading the side load between the bulkheads, I didnt think of that. But not sure how well a bolt in each end would work as the shaft would be spinning.

Say I put a 10mm thread in each end and put a 10mm bolt through the retaining plates I already have there. That would do it maybe??
Hinm i would need a bearing in between the bolt head and plate though otherwise there's a chance the bolt would undo due to the spinning shaft.

What do you have between the shaft and the forks at present?

If you have a retaining washer bolted onto the end of the shaft it will only rub against the face of the fork when it is pushed against it. If it's oiled then for the duration of it's life wear should not be that big an issue. Let's face it, it will be lucky to work for half an hour in total.

I think your assembly will be too heavy. 30mm thick hardox disc at that diameter will take most of your weight even with huge holes in it. 25mm bulkheads I'll be surprised if you can fit in there too.

This is good... this is the kind of pointers I need :-) thanks lads. Seems I'm thinking a little too big for FW haha.
i was going to do weight calculations and adjust bulkhead thickness and disk thickness to suit.
So, If I put some retaining bolts in each side so spread side load is this then a viable weapon assembly then?

Just for a sense of perspective, my featherweight drisc (180 diameter) has 6mm hardox bulkheads and equivalent of about 16mm disc, and my larger spinner (also featherweight but 300mm diameter) has 20mm HDPE bulkheads and an 8mm thick disc - the latter setup being based on Inertia XL which did a good number of events without breaking too heavily

So in a nutshell I'd agree you're thinking too big haha, 15mm aluminium and a 15mm or so disc should see you sorted I think depending on your disc design. Would also heavily recommend a dead shaft over a live one - it increases the strength of the bulkheads massively for if you take a hit from a horizontal spinner

Ohhhhh yes... more strength because the fixed shaft is acting as a brace between the 2 bulkheads. I get your thinking :-)
thanks everyone for all the tips. :-)