Clock movement question
Clock movement question
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Jonboy_t

Original Poster:

5,038 posts

214 months

Wednesday 7th March 2012
quotequote all
Hi all. I've just changed my brake discs and was going to use one of the old ones to make a wall clock for the garage.

Does anyone know if it's possible to change or extend the spindle (I believe that's what it's called) on a clock movement so I could use something like drill bits or long screws as the hands for the clock?

I haven't bought one yet, but was just going to grab a cheapey off eBay for a couple of quid and then manipulate it to suit, but just not sure if it would work or just make it too heavy to be accurate (as accurate as a garage clock needs to be!).

Tanguero

4,535 posts

232 months

Wednesday 7th March 2012
quotequote all
I think you will find that drill bits or screws will be so heavy that your clock will only be right twice a day i.e. it wont run at all! The hands on cheapo clock movements need to be fairly light.

Jonboy_t

Original Poster:

5,038 posts

214 months

Wednesday 7th March 2012
quotequote all
Tanguero said:
I think you will find that drill bits or screws will be so heavy that your clock will only be right twice a day i.e. it wont run at all! The hands on cheapo clock movements need to be fairly light.
Good point, didn't think of that!

Hmmm, what to use, what to use....

andy_s

19,857 posts

290 months

Wednesday 7th March 2012
quotequote all
Use counterweighted hands.

Tanguero

4,535 posts

232 months

Wednesday 7th March 2012
quotequote all
andy_s said:
Use counterweighted hands.
Nice Idea!

Counter weight by MIGing an appropriate size nut onto the end of the drill bit? You might want to anneal the drill bit before you try and put a hole through it though, or use a carbide drill.

andy_s

19,857 posts

290 months

Wednesday 7th March 2012
quotequote all
Or use a source with more torque:



smile

Jonboy_t

Original Poster:

5,038 posts

214 months

Wednesday 7th March 2012
quotequote all
Tanguero said:
andy_s said:
Use counterweighted hands.
Nice Idea!

Counter weight by MIGing an appropriate size nut onto the end of the drill bit? You might want to anneal the drill bit before you try and put a hole through it though, or use a carbide drill.
Top idea!!

Although there is more thinking to be done on how to make sure the hands pass under one another cleanly (hence, trying to extend the spindle) and with a counterweight, it would mean a further few mm to take into account.


Tanguero

4,535 posts

232 months

Wednesday 7th March 2012
quotequote all
How about welding a nut on, flush with one side of the drill bit, then grinding the back of the nut and half the thickness of the drill bit away, giving you a flat back. Then you only have to worry about the hands passing at half the thickness of the drill.

The hour hand drill bit will be thinner so you could probably drill and ream a hole to fit the hour wheel of the movement with a blind hole in the minute hand to go onto the cannon pinion. You would probably need to do a bit of calculation based on the weight and thickness of a nut to get the counter weights right but it wouldn't be too difficult.

Jonboy_t

Original Poster:

5,038 posts

214 months

Wednesday 7th March 2012
quotequote all
Tanguero said:
How about welding a nut on, flush with one side of the drill bit, then grinding the back of the nut and half the thickness of the drill bit away, giving you a flat back. Then you only have to worry about the hands passing at half the thickness of the drill.

The hour hand drill bit will be thinner so you could probably drill and ream a hole to fit the hour wheel of the movement with a blind hole in the minute hand to go onto the cannon pinion. You would probably need to do a bit of calculation based on the weight and thickness of a nut to get the counter weights right but it wouldn't be too difficult.
That's a plan!

The counterweight shouldn't be an issue, I think it should be weight/length x length of drill bit after spindle. i.e. drill bit is 100g and 100mm long, the minute hand is 80mm on one side of spindle and 20mm on the other. The counterbalance weight would need to be 80g.

Top work chaps, pics will be posted once it's finished (if it looks OK!)

Jonboy_t

Original Poster:

5,038 posts

214 months

Wednesday 7th March 2012
quotequote all
Another thought - Coach bolts.

They are long and relatively light in the shaft (ooo err) but have a heavy nut on the head. Should still look 'garagey' enough for what I want it for, but would save me having to look at my awful attempt at welding whenever I was working in there! Perhaps a bit of fettling would be needed, but a lot less than drill bits.

Tanguero

4,535 posts

232 months

Wednesday 7th March 2012
quotequote all
Use HSS drill bits and they are already 'blued'...