I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?

unk wrote in :

I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?


Not a reliable one. You'd need to know the depth of the flat for both
the shaft and the recess to work it out by triganometry, and any rounding
of the edges of the flat would cause significant error.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL

Ian Malcolm wrote:
unk wrote in :

I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?


Not a reliable one. You'd need to know the depth of the flat for both
the shaft and the recess to work it out by triganometry, and any rounding
of the edges of the flat would cause significant error.

Agreed. Things to try to shimming what I assumed to be small diameter
shafting on plastic would be plain string, or even pieces of rubber band.
They both have enough give and cost nothing and keep things simple.

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

On Tue, 17 Nov 2015 20:46:40 -0500, Steve Walker wrote:

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.

On Wed, 18 Nov 2015 11:29:17 -0000 (UTC), unk
wrote:

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.

May not be helpful to your application, but silicone can be thinned
with acetone and painted on. Still sets and seems just as strong.
Think it was type 1 that worked better, the one that has that has
the strong odor.
--
William

unk wrote:
On Tue, 17 Nov 2015 20:46:40 -0500, Steve Walker wrote:

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

I've never had good luck with silicone as any type of shaft lock or
material to keep shafts and collars tight. It just has no strength, and
doesn't bond all that good to things like shafts anyways, plus it adds no
pressure to keep whatever on the shaft tight.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.

RTV gasket silicone has fillers and dries fast, but again, it's a poor
material for this type of use.

On Wed, 18 Nov 2015 11:29:17 -0000 (UTC), unk wrote:

On Tue, 17 Nov 2015 20:46:40 -0500, Steve Walker wrote:

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.

Shoe Goo ought to work just fine.

--
The most powerful factors in the world are clear
ideas in the minds of energetic men of good will.
-- J. Arthur Thomson

On 11/18/2015 6:29 AM, unk wrote:
On Tue, 17 Nov 2015 20:46:40 -0500, Steve Walker wrote:

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.



Probably a little loose on purpose, to keep vibration from spreading,
OR, maybe so the prop and shaft will beat themselves to pieces. Planned
obsolescence. I would use softer silicone, to absorb the vibration. Make
sure the prop and shaft are perpendicular to each other while drying.

On Sat, 21 Nov 2015 15:26:52 -0500, Steve Walker
wrote:

On 11/18/2015 6:29 AM, unk wrote:
On Tue, 17 Nov 2015 20:46:40 -0500, Steve Walker wrote:

On 11/17/2015 4:14 AM, unk wrote:
I've just started playing with quadcopters, these are really neat toys.

One variety of cheap ones drive a moulded plastic prop (x4) with a d.

These are all loose about the same amount. I can easily measure how
loose by angle.

Is there a formula to calculate the shim from the angle?



Little bit of silicone caulk.

Thanks guys.

You have to be able to remove props, so something like a silicone that
will release from the steel and nylon-ish plastic could be good enough,
just scrape it off and squirt some more in.

The issue is that the thing is jittery and I suspect it's the props
wobbling between driven and driving. What's the hardest when set type of
silicone you can get in a small tube? Bonus points if it cures fast.



Probably a little loose on purpose, to keep vibration from spreading,
OR, maybe so the prop and shaft will beat themselves to pieces. Planned
obsolescence. I would use softer silicone, to absorb the vibration. Make
sure the prop and shaft are perpendicular to each other while drying.

3M 5200, 1hr cure.

Just dont ever plan on taking it apart again.

Gunner

On Saturday, November 21, 2015 at 6:26:56 PM UTC-5, Gunner Asch wrote:


3M 5200, 1hr cure.

Just dont ever plan on taking it apart again.

Gunner

Lowes sells some Locktite polyurethane adhesive that is about $4.50 for a tube. They are discontinuing the 3M 5200. The 3m is suppose to be really good , but all polyurethane adhesives need to be used within 24 hours of breaking the seal. The 3m 5200 is kind of spendy for doing a little job.

Dan