Rubber, or any material similar to rubber. It will be pushed onto
a standard 608 bearing, like a tire onto a wheel. Thickness must
be at least 1/8 inch. A material like Delrin might be too hard but
it's a possibility. I guess plastics like HDPE might work. Maybe a
pipe of some such material with 22 mm ID could be sliced. My
ability to shape/machine material is very limited. I need need 10
or more pieces.
It needs to absorb some shock and be durable. But at the moment
I'm mostly interested in finding possibilities with 22 mm ID.
Thanks.
In reply to the question about my application...
The shock and durability requirement would be much less than an
inline skate wheel. That still might seem like a lot, but the
force is always glancing since the wheel is on a bearing. And in
this case, the bearings might be in two rows, staggered (like in
the link below, but much smaller). Also, these small wheels will
not be used for pushing, so there will be no typical wear like on
a skate wheel. Also, they will not be in contact with the ground
during ordinary use, only when the front wheel dips into a pit or
pothole. There is a radical example of applied force, like when
jumping up onto a curb and landing in the middle of the frame, but
I'm interested only a reasonably functional version.
http://bontskates.yuku.com/topic/893/Bont-7-wheel-concept-frame#.T1pZynklquJ
I'm sure Alexander Bont came up with the concept of staggered
skate wheels before I did, but (with all due respect) the best
application of staggered wheels is rough terrain skating, not
downhill.
There are lots of off-road inline skates that are supposed to
resemble skis, but with only two wheels (one in front and one in
back), they are nothing like skis. They are like an all-or-nothing
seesaw. In order to resemble skis (on dry land), skates must have
center wheels like an ordinary inline skate. Only the front wheel
size matters for traversing obstacles on rough terrain. Trailing
wheels can be small if they are closely spaced. And if the center
wheels are not used normally, a medium or large rear wheel is
useful. If the center wheels are very small and homemade like what
I'm talking about, they won't be useful for turning, so they
should probably not normally contact the ground. So that while
turning the center wheels do not contact the ground, having two
staggered rows of bearing wheels might be too wide. The wider they
are, the higher off the ground they must be. Also possible is a
tank tread setup using something like a fan belt and only one row
of bearings.
The objective is to keep terrain from getting in between the
wheels so that the ride over rough terrain is smoother. With As
little device resistance as possible.
--
Thanks to the replies.
This is more detail.
http://www.bont.com/concept.htm
At least two of the concepts on that page are good for rough
terrain skating. The staggered wheels and the large front with
small trailing wheels (the large rear wheel makes no difference).
But they are promoted for speed skating. Those two designs might
be good for speed skating, but they are obviously better suited
for street or off-road skating. That's kind of weird IMO that they
don't say that since they make off-road skates.
I know the large front wheel design is good for street and rough
terrain skating, because I've been using big front wheel skates
for years. The staggered wheel concept is obviously good for rough
terrain. With experience skating on rough terrain, you can tell by
just looking at the lack of space between the wheels.
In article <[email protected]>, Dean Hoffman says...
>
> On 3/9/12 6:56 AM, John Doe wrote:
> > Rubber, or any material similar to rubber. It will be pushed onto
> > a standard 608 bearing, like a tire onto a wheel. Thickness must
> > be at least 1/8 inch. A material like Delrin might be too hard but
> > it's a possibility. I guess plastics like HDPE might work. Maybe a
> > pipe of some such material with 22 mm ID could be sliced. My
> > ability to shape/machine material is very limited. I need need 10
> > or more pieces.
> >
> > It needs to absorb some shock and be durable. But at the moment
> > I'm mostly interested in finding possibilities with 22 mm ID.
> >
> > Thanks.
>
> A propane torch to heat the material so it can expand might help.
Heating rubber with a propane torch generally produces more stink than
expansion.
On 3/9/2012 14:56, John Doe wrote:
> Rubber, or any material similar to rubber. It will be pushed onto
> a standard 608 bearing, like a tire onto a wheel. Thickness must
> be at least 1/8 inch. A material like Delrin might be too hard but
> it's a possibility. I guess plastics like HDPE might work. Maybe a
> pipe of some such material with 22 mm ID could be sliced. My
> ability to shape/machine material is very limited. I need need 10
> or more pieces.
>
> It needs to absorb some shock and be durable. But at the moment
> I'm mostly interested in finding possibilities with 22 mm ID.
Fiber enforced rubber hose, like radiator hose, works fine
and is durable. It is possible to push it around an object
sligtly bigger than the ID of the rubber hose, like 19mm ID
hose to 21mm OD rod.. Easy to cut with knife.
On 3/9/12 6:56 AM, John Doe wrote:
> Rubber, or any material similar to rubber. It will be pushed onto
> a standard 608 bearing, like a tire onto a wheel. Thickness must
> be at least 1/8 inch. A material like Delrin might be too hard but
> it's a possibility. I guess plastics like HDPE might work. Maybe a
> pipe of some such material with 22 mm ID could be sliced. My
> ability to shape/machine material is very limited. I need need 10
> or more pieces.
>
> It needs to absorb some shock and be durable. But at the moment
> I'm mostly interested in finding possibilities with 22 mm ID.
>
> Thanks.
A propane torch to heat the material so it can expand might help.
John,
Hose with an ID of 7/8" is 22.23 mm. Wrap a piece of tape around the
circumference of the bearing and you should be able to stretch rubber hose
on. Or use an appropriate glue on the circumference of the bearing. Rubber
cement comes to mind. Hydraulic hose should have the appropriate wall
thickness.
There are a great variety of hoses with an ID of 7/8"
Dave M.
.
"John Doe" <[email protected]> wrote in message
news:[email protected]...
> Rubber, or any material similar to rubber. It will be pushed onto
> a standard 608 bearing, like a tire onto a wheel. Thickness must
> be at least 1/8 inch. A material like Delrin might be too hard but
> it's a possibility. I guess plastics like HDPE might work. Maybe a
> pipe of some such material with 22 mm ID could be sliced. My
> ability to shape/machine material is very limited. I need need 10
> or more pieces.
>
> It needs to absorb some shock and be durable. But at the moment
> I'm mostly interested in finding possibilities with 22 mm ID.
>
> Thanks.
Maybe:
O rings
Can you buy "flat" - rings
silicone surgical tube
Nylon beverage tube - get it hot to slip on
3/4" rubber automotive heater pipe
3/4" coloured silicone tube autoparts sell for "customising"
Adhesive lined heatshrink (a bit thin)
Places that make seals will freeze & custom machine nitrile rubber to
whatever you want.
Look in the spare parts catalogs for sliding aluminium door fittings - lots
of cheap roller wheels etc.
What sort of load are you applying / whats the application?