Chronicles of a home-made plate system

[SunSurfer]

1/ This is the rear hinge unit.

2/ The screws attaching the hinge to the UHMWPE go into a barrel nut that has a smooth 9mm outer diam shaft, and a 2mm deep x 14mm diam cap. The nuts are inset into the base of the plastic and only the smooth shaft of the nut is in contact with the plastic to avoid the thread of the screw wearing away the plastic under loads.

3/ bjvircks post 18 has the guts of the design correct apart from the lack of barrel nuts through the plastic. (not shown in the original photos) and similarly T-nuts will be used in the attachment points for the bindings / toe & heel units on the plate.

4/ So far all the plates I've seen seem to be rigid.

I have a cambered flexible slalom skateboard I built 20 odd years ago, the camber helping to soak up vibration and momentary losses of traction in tight turns. I haven't seen a flexible plate yet but thought that the flex might add yet another vertical shock absorbing capability into the system, a bit like Fin was trying to build into his HFP.

Half the fun of all this will be experimenting and seeing what the result is, comparing to a rigid plate. The flex will add to the amount of slide motion that needs to be accommodated.

5/ The strength of the 3mm plate in the hinge is a concern. I looked far and wide for various hinge options including marine stainless steel hinges (too heavy). This was the only extrusion I could find that was anywhere near suitable and had a hinge pin of the kind of diameter I would even begin to entertain using. Very few hinges are available locally that are wider than about 100mm.

However, the hinge is also directly abutting both the top and rear/front of the plastic plate and so supported by it. The plate will also abutt the hinge along the hinge's length so that the forces the rider applies will be also transmitted along the whole length of the hinge. All the attachment screws for the hinge have been placed reasonably close to the hinge axis to minimise the leverage forces on the 3mm aluminium. If it's strong enough when set up this way then it allows me to custom make hinges that are suitable for my wider boards.As well, having the front floating reduces the decelleration shocks the hinge will have to cope with from impacts with bumps etc. Whether it will cope with a full nose burying cartwheel is a different matter!

6/ My academic background is medicine, not engineering. NZ is pretty isolated in carving snowboard terms. I'm aware that there are some very knowledgeable people on the board so I'm very much interested in everyone's constructive thoughts and opinions. If the dialogue helps me and helps others better understand what plates do, so much the better.

Thanks to all who have contributed so far.

Pictures of the front unit will be few days away yet. I've got a fair amount of other work that has to be done so the workshop will have to wait.

SunSurfer

[NateW]

I like where this is going. :)

Consider moving the hinge axis forward, as close to the 4x4 screws as possible. That should put less stress on the plastic in between them, and it would put a smaller footprint on the board, for less disruption of the board's flex.

[leeho730]

Do you recon there could be a problem with the sliding mechanism, especially in terms of vibration?

[SunSurfer]

......Consider moving the hinge axis forward, as close to the 4x4 screws as possible. That should put less stress on the plastic in between them, and it would put a smaller footprint on the board, for less disruption of the board's flex.

The board (Riot Supercarve 180cm) I'm prototyping this for has a max distance of 50cm between it's outermost binding inserts. With my preferred stance width of 50cm, the plate needs to be substantially longer, and to support the plate, and prevent plate overhang and board flex leading to plate tip hitting the board I've had to move the hinge away from the binding inserts in the board.

I would prefer to have them as close as possible as NateW suggests, ideally the hinge attachment screws would go directly into inserts in the board, but that would mean modifying the board, something I'm trying to avoid.

Different boards have different insert distances, so a versatile system would have some ability to cope with those differences while still using the standard inserts.

The board setup is forcing some compromises, but at the same time the difficulties it throws up are making me think very hard about ways around them.

SunSurfer

[SunSurfer]

Back in 1902 in USA there was a race to develop heavier than air flight. Samuel Langley was a world renowned scientist, inventor and engineer. He had at his disposal the best talent in the US for machinists, craftsman, researchers, etc that big money could buy. He and his large team repeatedly failed to create a working aircraft. At the same time a couple of poor uneducated bicycle mechanics who knew almost nothing of 'traditional science' just did things their own way. Wilber and Orville Wright and succeeded where the best experts did not.

http://en.wikipedia.org/wiki/Richard_Pearse

I couldn't let this one go by! New Zealanders have been mucking around in their sheds for a long time! New Zealander Richard Pearse is thought to have successfully flown and landed a powered, heavier than air machine 9 months before the Wrights flew at Kitty Hawk.

SunSurfer

[Jack M]

http://en.wikipedia.org/wiki/Richard_Pearse

I couldn't let this one go by! New Zealanders have been mucking around in their sheds for a long time! New Zealander Richard Pearse is thought to have successfully flown and landed a powered, heavier than air machine 9 months before the Wrights flew at Kitty Hawk.

SunSurfer

"The documentary evidence to support such a claim remains open to interpretation, however, and he does not appear to have developed his aircraft to the same degree as the Wright brothers did, in respect of sustained, controlled flight"

No wonder he doesn't get the credit. Wright Bros. FTW! :D

[lonbordin]

All these different people all over the world working on building the first flying machine [commercially viable snowboard plate system] at the same time.

Brought it back on-topic for ya' OP!

[Bruce Varsava]

So I finally got to ride the Apex plate last weekend. One of the early protos for the cdn team. Definitely has potential for race and freecarve but as expected, weight and cost need to come down. Chatting with some of the developers, it did actually make bad boards good, to a certain degree. Most unique feel was the clean line the board will cut while not affected by what your feet are doing. I haven't ridden hangls in a while but I recall they really isolated the feel whereas the Apex let me feel what the edge was doing a bit more. This is a unique situation as opposed to the Hangl ( complex extrusions) as it won't take too much work for all the home brew versions to start popping up. At the race, I saw numerous versions already in use so lots of fun yet to come! Most common are guys using broken boards as the plate and making up the hardware underneath.

The games are over but let the games begin:biggthump

Here is a message I just got from Apex Composites on Monday 8th

Hi Bruce,

Yes we will be releasing some plates soon. We will be selling them in the next couple of weeks. The insert pattern is exactly the same as the latest hangl pattern. If you don’t have it, I’m sure I can send you a DXF with the lay-out. Also, we are working on an adaptor plate that will allow it to be attached to any board through the standard bindings holes. We anticipate a slight degradation in performance, but something only the elite world cup athlete would probably feel.

We’re working out some details this week and I should be able to get back to you soon.

Gerry Kavanaugh

Apex Composites Inc.

3375 North Service Road A1-2

Burlington, Ontario L7N 3G2

[Jack M]

So I finally got to ride the Apex plate last weekend. One of the early protos for the cdn team. Definitely has potential for race and freecarve but as expected, weight and cost need to come down. Chatting with some of the developers, it did actually make bad boards good, to a certain degree. Most unique feel was the clean line the board will cut while not affected by what your feet are doing. I haven't ridden hangls in a while but I recall they really isolated the feel whereas the Apex let me feel what the edge was doing a bit more.

Sounds great. Vist eliminates some snow-feel as well, and for me it would take some getting used to. It was a problem at first. But for my needs the weight is a dealbreaker.

[lowrider]

I think i recall making a statement similar to that a few weeks ago. I think it went "a plate will make any board better " provided it's the right kind of plate. anybody got any old or broken boards?

[zoltan]

So I finally got to ride the Apex plate last weekend...

Any pictures of the Apex plate?

[Bruce Varsava]

It pretty much looks the same as the video you can see here

http://www.thestar.com/videozone/747896

[SunSurfer]

It pretty much looks the same as the video you can see here

http://www.thestar.com/videozone/747896

Many of us have seen the video, and I've pored over screenshots from it to try to work out a number of things. Are you able to answer any of these questions?

1/ Is the carbon fibre plate essentially hinged to the snowboard at both attachment points and the hinge point able to slide at one end, or, is it something different?

2/ If Q1 = Yes, is the slide at the front?

3/ Can you describe the mechanism at the two attachment points in more detail?

SunSurfer

[Jack M]

1/ Is the carbon fibre plate essentially hinged to the snowboard at both attachment points and the hinge point able to slide at one end, or, is it something different?

2/ If Q1 = Yes, is the slide at the front?

I've never seen the plate in person, but I'm pretty confident the answers to these two questions are yes.

However as they've said, even if you did see it in person you wouldn't be able to see everything that's going on. The video hints at another dimension of suspension, in the vertical direction. Not sure how they're doing that.

[Bruce Varsava]

Many of us have seen the video, and I've pored over screenshots from it to try to work out a number of things. Are you able to answer any of these questions?

1/ Is the carbon fibre plate essentially hinged to the snowboard at both attachment points and the hinge point able to slide at one end, or, is it something different?

2/ If Q1 = Yes, is the slide at the front?

3/ Can you describe the mechanism at the two attachment points in more detail?

SunSurfer

I just rode it and it was covered in snow so I didn't take too long of a look at it. Both sides are hinged and the one I saw had the slide mechanism at the rear. Without taking it apart, you can't see all the details

[bjvircks]

some apex details Top view of front attach & side view of front attach

[bjvircks]

looking closely here you can see some float front, some float rear.

[Seb]

looking closely here you can see some float front, some float rear.

when it float on the rear it's better on flat course but I always find it to big of a change and race on floating front evan if it was flat cause it make your nose feel way stiffer

[zoltan]

Does anyone know why the Apex system has so much overhang on the front?

[www.oldsnowboards.com]

Stiff is of course relative. The question or statement has come up several times of if they are ridgid. As in, not flexible. Most of the plates do in fact flex, the amount and degree is of course a part of the total formula. Simply put, most DO flex quite a bit, they are NOT completely rigid.

Home builders. Perhaps now is a good time to ask the original external flex dampening innovator himself? Most if not all of these designs stem from work Mike Tinkler has been doing for many years. Respecting the history and those who are pioneer's in it goes a long way to earning their knowledge and support. Just a thought. :) Have at it.

[www.oldsnowboards.com]

Does anyone know why the Apex system has so much overhang on the front?

Several of the systems do. Think "Snow Stix" or overload leaf springs.

[lowrider]

Helps protect the nose if you stuff it.Looks cool too especially if it has a big COILER sticker on it .

[SunSurfer]

Have got the slide mechanism made to my satisfaction.

The photo has the UHMWPE centre box raised about 2mm to help show the way in which the slide works. In use the box has just a 1mm raise under it to allow the hinge unit to slide.

The other photo shows the aluminium plate that holds the centre box down, and restricts the movement of the hinge unit.

The front hinge is identical to the rear and placed identically to the rear in relation to the binding inserts on the snowboard when the board is in the unridden position. When the board is decambered the UHMWPE box moves towards the rear relative to the front hinge. The sliding surfaces are

a) underneath - UHMWPE hinge unit / snowboard deck

b) sides - UHMWPE box /UHMWPE hinge unit

c) top - 1mm thick cutting mat plastic layer under aluminium plate / UHMWPE hinge unit

To quote from Wikipedia UHMWPE "has extremely low moisture absorption, has a very low coefficient of friction, is self-lubricating, and is highly resistant to abrasion (15 times more resistant to abrasion than carbon steel). Its coefficient of friction is significantly lower than that of nylon and acetal, and is comparable to that of Teflon, but UHMWPE has better abrasion resistance than Teflon"

I haven't yet resolved the final shape of the aluminium plate that holds the centre box in place, nor have I finished shaping the excess UHMWPE from the hinge unit.

Next to build the top plate. Rigid first, then a lightly cambered flexing version.

SunSurfer

[Corey]

Thanks for posting this! I'm considering something similar but I'm in the 'analysis paralysis' stage where I can't decide exactly what to do.

One thought: The sharp inside corners on the hinge unit have me concerned. They create stress risers that may lead to cracks. It's a little late now but a rounded corner will greatly reduce the stress in the plastic. Then again, it's a test part so maybe it won't be ridden long enough to develop cracks.

Throw a radius on any other inside corners you'll be cutting into future parts to reduce the chances of failure. The bigger the better.

[Jack M]

For the sliding part, I think you'll need to make the stationary center square either out of metal or slightly thicker than the part that slides. As you have it now I think the part that slides will get clamped down when you tighten the board screws and the center square compresses.....?