OT(?): Could somebody make a metal shaft for me? (for payment of course)
Mathew J. Newton
I am hoping some kind and able soul out there with a lathe and/or milling
machine might be able to help me out here....
At the risk of sounding like I've got too much spare time on my hands I
am in the middle of project building a network-enabled cat feeder. The
current design is based around a cereal dispenser driven by a high-torque/
low-revs motor, the latter being controlled by a modified Cisco switch.
The following diagram shows roughly what I am doing from a mechanical
perspective:
http://www.newtonnet.co.uk/permanent/feederdiagram.png
The cereal dispenser contains a rubber flapper mechanism which
accommodates a plastic shaft connected to a knob. Whilst I have managed
to separate the shaft from the knob and connected everything up I am
concerned that over time the high torque required when food gets caught
in the flapper will cause the connection to the brass coupling to fail.
This is based on the fact that the plastic shaft is rather soft and is
not held all that firmly by the grub screw in the coupling. I have
considered inserting a metal shim of some sort but I really can't see it
lasting.
Hence, I am wanting to replace the plastic shaft with something made out
of metal. Unfortunately whilst my apprenticeship days taught me the
skills to do this I do not have access to the necessary machines to do so.
Would anybody be able to help me out here? That kind person would be
suitably compensated as required. I have made a drawing showing the
necessary dimensions (using Word - my teachers would not have been
impressed!):
http://www.newtonnet.co.uk/permanent/shaftdrawing.png
As you can see, the coupling to the motor (right-hand side) is required
to be smaller the main shaft - I could not find a shaft coupling any
bigger than 6mm (the motor shaft is also 6mm). The rather strange
(specific) dimensions of the main shaft (which is fully inserted into the
flapper body) is, I believe, a result of it being US-made and hence of
imperial measurements.
Happy to provide further info and clarification if required. Indeed I am
all ears to alternative ideas too and/or suggestions as to who/where
might be able to make this shaft for me.
Regards,
Mathew
Harry Bloomfield
I could do that for you, providing you supplied the mild steel and
could file the flats on each end.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Lobster
> am in the middle of project building a network-enabled cat feeder.
Fantastic! Now there are 4 words I never thought I'd see in the same
sentence...
Can't help I'm afraid; but isn't there a website out there somewhere
where you can enter in requests for jobs like this, and people bid a
price to do it? Don't recall any details but maybe someone else will?
David
Mathew Newton
<harry.m1...@NOSPAM.tiscali.co.uk> wrote:
> I could do that for you, providing you supplied the mild steel and
> could file the flats on each end.
Hi Harry,
To clarify, the shaft is D-shaped all the way along hence manual
filing could be problematic...? This is why I thought a milling
machine might be required...
(I can't believe I didn't mention it being D-shaped given it is such a
fundamental point! Sorry about that...)
Mathew
Harry Bloomfield
I don't have such, but I thought the D shape was just to enable it to
be firmly fixed at each end.
Mathew Newton
<harry.m1...@NOSPAM.tiscali.co.uk> wrote:
> I don't have such, but I thought the D shape was just to enable it to
> be firmly fixed at each end.
Unfortunately the design of the flapper is such that the shaft needs
fully inserting - it thus needs to be flat across the whole length. I
have modified the drawing to hopefully remove the ambiguity.
Thank you anyway for the initial offer.
Mathew
Mathew Newton
> Mathew J. Newton wrote:
> > am in the middle of project building a network-enabled cat feeder.
>
> Fantastic! Now there are 4 words I never thought I'd see in the same
> sentence...
The result of requirements creep unfortunately!
Whilst it started out as a simple timer-controlled dispenser it soon
became a bit more 'interactive'. It now has streaming video and a web-
based interface...!
If I can get it up-and-running (the software is now written, and the
electronics built) I'll be publishing details of the end result on a
website so finger's crossed I can get this shaft sorted.
Mathew
JimK
angle grinder?
JimK
Pete Verdon
> Hi all,
>
> I am hoping some kind and able soul out there with a lathe and/or milling
> machine might be able to help me out here....
If you don't get any joy on that basis, there's always these guys:
I believe they'll post to the UK and presumably the cost of sending such
a small part will be minimal.
I also have a work colleague who is thinking of retiring and then
earning some "pocket money" with jobs like this, but I'm not sure he'd
necessarily appreciate me touting for business on his behalf just yet :-)
Pete
The Natural Philosopher
Everything you need is probably there already.
http://www.technobots.co.uk/acatalog/
is a good read!
John Rumm
> On Nov 11, 8:56 pm, Harry Bloomfield
> <harry.m1...@NOSPAM.tiscali.co.uk> wrote:
>
>> I could do that for you, providing you supplied the mild steel and
>> could file the flats on each end.
>
> Hi Harry,
>
> To clarify, the shaft is D-shaped all the way along hence manual
> filing could be problematic...? This is why I thought a milling
> machine might be required...
On could possibly avoid the milling operation by turning it down from
square stock, and choosing your centre very carefully such that the
right amount of flat is left on one side when the final diameter is
reached.
I take it the smaller end is coaxial with the main shaft - therefore
there is a step in the flat section at that point?
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Mathew J. Newton
> I take it the smaller end is coaxial with the main shaft - therefore
> there is a step in the flat section at that point?
There is. Basically, the shaft rotates on a central line as if there
weren't any flats.
Mathew
Mathew J. Newton
> If you don't get any joy on that basis, there's always these guys:
>
> http://www.emachineshop.com/
I'll certainly check them out, not least given you get an instant price
if you design it with their free software! Looking though at their
samples prices it might still be a little steep though.
> I also have a work colleague who is thinking of retiring and then
> earning some "pocket money" with jobs like this, but I'm not sure he'd
> necessarily appreciate me touting for business on his behalf just yet
> :-)
I'd be happy to be his first customer... And would of course put a link
to his site (if he's going to have one) on my cat feeder pages! ;-)
Mathew
Mathew J. Newton
> http://www.technobots.co.uk/acatalog/
>
> is a good read!
Yeah I've been all over that site - I was really starting to think
robotics would be a great hobby to get into...
Unfortunately I didn't manage to find any suitable shafts... Basic round
shafts (of not quite the right size!) and similar raw materials but
nothing really close enough to what I'm after.
All good pointers and ideas guys though - I really do appreciate them.
Mathew
Roger Mills
Does it really need to be as accurate as your specification, if it only
rotates slowly? Does anything have to slide along the D-shaped shaft in
operation, or only in assembly. If the latter, can't you:
* Start with a length of 8mm mild steel rod
* Rotate it in a drill chuck, and use a file and emery cloth to reduce it to
7.6mm
* File the flat all the way along
* Bore out one end of the coupling - thus avoiding having to reduce the end
of the shaft to 6mm?
--
Cheers,
Roger
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Mathew J. Newton
> Does it really need to be as accurate as your specification, if it only
> rotates slowly?
Probably not. The measurements were just those obtained from the existing
shaft. I didn't want to round anything off in case it resulted in it
either not fitting, or being too loose for good grip (there is no grub
screw arrangement in the flapper end - it just sits inside a D-shaped
channel through its centre).
> Does anything have to slide along the D-shaped shaft in
> operation, or only in assembly. If the latter, can't you: * Start with a
> length of 8mm mild steel rod * Rotate it in a drill chuck, and use a
> file and emery cloth to reduce it to 7.6mm
Hmmm... interesting. Do you think that would work? I haven't got a pillar
drill - or were you just talking about a suitably-clamped standard drill?
> * File the flat all the way along
> * Bore out one end of the coupling - thus avoiding having to reduce the
> end of the shaft to 6mm?
I hadn't considered boring out the coupling either! I suppose though if I
can form the rest of the shaft with my 'homemade lathe' as per your
method above then I can just go a bit further with the small end..?
Mathew
Graham.
"Mathew Newton" <use...@newtonnet.co.uk> wrote in message news:829a0fe0-c26d-4e5a...@p35g2000yqh.googlegroups.com...
I'm intrested in the modified Cisco switch. Why is that needed?
--
Graham.
%Profound_observation%
geoff
<5cf045b0-3dfe-4f91...@z41g2000yqz.googlegroups.com>,
Mathew Newton <use...@newtonnet.co.uk> writes
Surely the flat is only required at each end
--
geoff
geoff
Newton <use...@newtonnet.co.uk> writes
>Hi all,
>
>I am hoping some kind and able soul out there with a lathe and/or milling
>machine might be able to help me out here....
>
>At the risk of sounding like I've got too much spare time on my hands I
>am in the middle of project building a network-enabled cat feeder. The
>current design is based around a cereal dispenser driven by a high-torque/
>low-revs motor, the latter being controlled by a modified Cisco switch.
>
of 3/8" SS, but I'm not sure when I might have time to do it
--
geoff
Nige Danton
> Newton <use...@newtonnet.co.uk> writes>Hi all,
>
> >I am hoping some kind and able soul out there with a lathe and/or milling
> >machine might be able to help me out here....
Ask in uk.rec.models.engineering lot's of very capable people there
who could do this.
--
Nige Danton
R
"Mathew J. Newton" <use...@newtonnet.co.uk> wrote in message
news:OnFKm.4095$Ym4....@text.news.virginmedia.com...
Post an "OT" request on Uk.Rec.Motorcycles and await "WUN" to appear......
Mathew J. Newton
>>To clarify, the shaft is D-shaped all the way along hence manual filing
>>could be problematic...?
>
> But why ?
>
> Surely the flat is only required at each end
Hi Geoff,
The 'flapper' has a D-channel all the way through it and whilst you could
just poke the shaft in by only a small amount this would work fine when
free-running. However, when food starts getting caught between the rubber
flapper blades and the container walls the torque required to turn it
increases significantly. At this point the plastic centre of the flapper
really needs a good grip on the shaft hence the more that's in there the
less the likelihood of something rounding off at this interface.
Mathew
Mathew J. Newton
> I'm intrested in the modified Cisco switch. Why is that needed?
I use it to interface the motor to the network. Basically, being a
managed switch you can disable/enable each switch port individually. With
some loopback adapters (shorted Ethernet plugs for want of a better
description) plugged into the ports you can thus switch the LEDs on/off.
I have piggybacked some connections to the LEDs to drive some transistors
which in turn activate relays to drive the motor forward/backwards as
required. The switch PSU also provides the power for the motor.
Of course the novelty of manually telnetting to the switch to do this
soon wears off and so I have a shell script on my server which automates
the process.
Mathew
NT
I'm not seeing the point. Cats dont overeat, so dry food can simply be
left for them, set out in several small pots to avoid spoilage. I'm
not saying this sort of approach is at all a good way to look after
cats, but if youre going to do it at least this removes the risk of
feeder failure from the loop.
What mechanism are you using for water?
NT
Roger Mills
Mathew J. Newton <use...@newtonnet.co.uk> wrote:
> On Wed, 11 Nov 2009 23:13:37 +0000, Roger Mills wrote:
>
>> Does anything have to slide along the D-shaped shaft in
>> operation, or only in assembly. If the latter, can't you: * Start
>> with a length of 8mm mild steel rod * Rotate it in a drill chuck,
>> and use a file and emery cloth to reduce it to 7.6mm
>
> Hmmm... interesting. Do you think that would work? I haven't got a
> pillar drill - or were you just talking about a suitably-clamped
> standard drill?
>
I had in mind using a horizontal drill stand. Even better if you can find a
bearing which will fit over the other end end of the shaft to support it
while you 'machine' it. [You might find a bearing on a router bit which
would do the job].
>> * Bore out one end of the coupling - thus avoiding having to reduce
>> the end of the shaft to 6mm?
>
> I hadn't considered boring out the coupling either! I suppose though
> if I can form the rest of the shaft with my 'homemade lathe' as per
> your method above then I can just go a bit further with the small
> end..?
>
I would have thought that it would be much easier to bore out the coupling
than to turn a 8mm shaft down to 6mm concentrically without a proper lathe
(whereas going from 8mm down to 7.6mm - if you really have to - is less of a
problem).
soup
> I am hoping some kind and able soul out there with a lathe and/or milling
> machine might be able to help me out here....
> The following diagram shows roughly what I am doing from a mechanical
> perspective:
> http://www.newtonnet.co.uk/permanent/feederdiagram.png
Can't help you with the machining (perhaps a quiet word with a local
technical college tutor/techy teacher at the local high school).
I would imagine a 'weak link' would be required rather than stalling the
motor,and possibly setting fire to the place, the weak link would 'give'
so it was fairly easy to replace perhaps the coupler with the two grub
screws could be made to be easily (relatively) broken so you could just
replace that rather than the shaft, the motor or one of the rubber vanes.
Mathew J. Newton
> I'm not seeing the point.
I'm afraid it's probably the child in me - have always liked making
things, particularly anything with an engineering element.
> What mechanism are you using for water?
Watering cans in the garden, the puddle that collects on the tarpaulin on
my ladders, etc etc. They won't drink anything else - and that includes
tapwater in a bowl! ;-)
Mathew
Mathew J. Newton
> Can't help you with the machining (perhaps a quiet word with a local
> technical college tutor/techy teacher at the local high school).
That's a good idea. I might pop down for a chat.
It's really quite sad that these skills/capabilities aren't in abundance.
I'm just as guilty though given I work with computers all day.
> I would imagine a 'weak link' would be required rather than stalling the
> motor,and possibly setting fire to the place, the weak link would 'give'
> so it was fairly easy to replace perhaps the coupler with the two grub
> screws could be made to be easily (relatively) broken so you could just
> replace that rather than the shaft, the motor or one of the rubber
> vanes.
I will almost certainly be monitoring (or rather controlling) each feed
so would be able to stop/reverse the motor should it stall. It has a
stall torque of 25kg-cm though so hopefully it won't come to that.
Mathew
Mathew J. Newton
> Ask in uk.rec.models.engineering lot's of very capable people there who
> could do this.
Thanks for the pointer Nige - a couple of guys over there have offered to
assist.
Thank you everyone for your thoughts and suggestions. Whilst computers
may have killed off in droves the numbers with the necessary skills/
equipment to do this sort of work the Internet does at least help with
finding the few that are left! ;-)
Cheers,
Mathew
Jules
Hmm, try telling that to our two male cats. I think they were probably
shire horses in former lives :-)
> set out in several small pots to avoid spoilage.
Although I kind of like that approach - something that essentially
introduces a full pot and takes away the previous pot (whether the
contents are completely consumed or not) at set intervals. It can still
fail in interesting ways, but eliminates the need to check that the
food dish is empty before pouring a known quantity in (or the need
to detect food level and only add enough so that the dish is 'full')
cheers
Jules
geoff
<no_...@nowhere.tv> writes
--
geoff
geoff
<jules.rich...@remove.this.gmail.com> writes
parts.
All that's required is an upturned plastic bottle, maybe with an
enlarged spout placed at the correct height above the bowl, removing
food allows more food to drop down
Anything else (refreshing food, paddles, and other moving parts) is just
playing around for the sake of it
KISS ... as they say
--
geoff
Lobster
> On Thu, 12 Nov 2009 04:57:53 -0800, NT wrote:
>> I'm not seeing the point. Cats dont overeat
Yeah, where on earth do you get that that from?! See
<http://images.google.co.uk/images?hl=en&source=hp&q=fat+cat&gbv=2&aq=f&oq=>
> Hmm, try telling that to our two male cats. I think they were probably
> shire horses in former lives :-)
And ours...
Mathew Newton
> All that's required is an upturned plastic bottle, maybe with an
> enlarged spout placed at the correct height above the bowl, removing
> food allows more food to drop down
In theory, yes.
I bought one to try it out though and it didn't work - the shape of
the food was such that it wouldn't always fall down properly - the
cats ended up effectively digging it out and attacking the whole thing
in frustration. I might as well have put a big pile of food down for
all it was worth!
Mathew
NT
The problem with that proposed mechanism is spoilage. As cats eat they
leave saliva behind, and spoilage results. Serving fresh food on top
of spoiled food isn't workable or in any sense safe.
Several small pots, each with a book on top of it, normally results in
each potful being eaten before the next one is 'opened'
All moving parts do is introduce significant risk.
NT
geoff
<adfe95bf-8158-4f40...@o10g2000yqa.googlegroups.com>,
Mathew Newton <use...@newtonnet.co.uk> writes
>On Nov 12, 11:27 pm, geoff <ra...@kateda.org> wrote:
>
>> All that's required is an upturned plastic bottle, maybe with an
>> enlarged spout placed at the correct height above the bowl, removing
>> food allows more food to drop down
>
>In theory, yes.
>
>I bought one to try it out though and it didn't work - the shape of
>the food was such that it wouldn't always fall down properly
Larger hole required, then
> - the
>cats ended up effectively digging it out and attacking the whole thing
>in frustration. I might as well have put a big pile of food down for
>all it was worth!
>
That's what I do ...
--
geoff
Mathew Newton
> Hi all,
>
> I am hoping some kind and able soul out there with a lathe and/or milling
> machine might be able to help me out here....
>
> At the risk of sounding like I've got too much spare time on my hands I
> current design is based around a cereal dispenser driven by a high-torque/
> low-revs motor, the latter being controlled by a modified Cisco switch.
In case anyone is interested in how this turned out I'm happy to
report it went well - better than expected in fact!
http://www.newtonnet.co.uk/catfeeder
Mathew
Ash
> report it went well - better than expected in fact!
>
> http://www.newtonnet.co.uk/catfeeder
>
> Mathew
Excellent! Our last cat would have had one look at the thing and eaten it
along with the biscuits ... he was a hungry nosed fat cat who would have
breakfast with us and then nip down the street and have breakfast with at
least two other neighbours before returning for more food and giving that
"I'm hungry Feed Me" look. He even got too big/fat for the cat flap and took
to sticking his head through the cat flap and meowing (screeching) until we
opened the door for him.
Ash
Stuart Noble
Am I just easily impressed, or is that bloody brilliant?
Jules
> In case anyone is interested in how this turned out I'm happy to
> report it went well - better than expected in fact!
>
> http://www.newtonnet.co.uk/catfeeder
OK,
a) That's rather good.
b) I'm really impressed with the write-up. Homebrewing stuff is one thing,
but conveying what you've done to others is just as hard, I think...
Now you need an internet-enabled self-cleaning litter-box ;)
John Rumm
Nice job - very well done! ;-)
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Mathew Newton
wrote:
> Now you need an internet-enabled self-cleaning litter-box ;)
The neighbour often sits in his garden using his laptop if that
counts...? ;-)
Mathew
Dave Liquorice
>> http://www.newtonnet.co.uk/catfeeder
>
> Nice job - very well done! ;-)
Yeah, good stuff. Could be useful here though not having a redundant
managed switch kicking about I'd probably use an Arduino with an
ethernet shield and have it all self contained. That is the
relatively easy bit, the food handling is the hard part but there
seems to be an "off the shelf" solution for that. B-)
--
Cheers
Dave.