FW Spinner Advice please :-)

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?