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Member postings for Chris TickTock

Here is a list of all the postings Chris TickTock has made in our forums. Click on a thread name to jump to the thread.

Thread: Increasing Friction??
16/01/2021 15:38:09

Update.

I thought about this over night. If I think if a small part of a clock is of questionable design and merit should I 'improve' it. Well you will get different opinions that goes without saying. But if its a minor variation from original design I think it is acceptable. The person doing the repair along with the owner must decide here it was much easier just me.

Anyway i have done it.

regards

Chrisalteration.jpg

Edited By Chris TickTock on 16/01/2021 15:38:37

15/01/2021 18:26:10
Posted by Tim Stevens on 15/01/2021 18:15:36:

It may be helpful to put a washer of what is known as 'red fibre' - used for fibre washers on petrol fittings and in electrical parts as an insulator - between the brass surfaces. Search hard and you might even find the same stuff but black, if you prefer.

I am guessing that the crutch is set by rotating it to what seems a good position, listening to the ratios between tick and tock, and making final adjustment again by sliding. And once set, until small brother or big dog nudges the whole thing again, it will carry on ticking and tocking steadily with both parts of the device moving in unison.

Cheers, Tim

Edited By Tim Stevens on 15/01/2021 18:16:30

Spot on Tim. Personally I do not like this set up as clever as it might be it is prone to lose beat. The clock is a trio gong and while if left alone the position will hold it is not as reliable as other methods such as fixed position or grub screw. Others might disagree but that is my take. If I was a botcher I would solder the thing up as it is my clock but it goes against the grain. fibre washer noted, thanks.

Chris

15/01/2021 18:19:05

Thanks Guys,

I have made a spring to replace the original one. I annealed a piece of old mainspring first made the spring bent it then hardened it. Unfortunately the spring broke when fitting die to the metal being too brittle when clamped with dental pliers to get the pin in. I think after hardening I will temper next time and see if it improves the situation. After all a spring has to have give in it or it is not much of a spring but has to be hard enough to retain shape.

Chris

 

Edited By Chris TickTock on 15/01/2021 18:19:32

14/01/2021 18:31:44

Thanks for link I think I will try a small washer behind the spring first.

Regards

Chris

14/01/2021 18:25:49
Posted by Michael Gilligan on 14/01/2021 18:12:08:
Posted by Chris TickTock on 14/01/2021 17:43:05:

[…]

The pressure of the spring is there to maintain position but allow adjustment if necessary.

[…]

Optimising friction means the clock is less likely to go out of beat.

I would be grateful for any suggestions on possible solutions.

regards

Chris

.

That’s strange :

I always thought that optimised spring pressure allowed the beat to self-adjust.

I shall watch and learn.

MichaelG.

Edited By Michael Gilligan on 14/01/2021 18:12:40

This mechanism on this clock  is not intended to be self adjusting.

Chris

Edited By Chris TickTock on 14/01/2021 18:26:15

14/01/2021 18:11:49
Posted by Bob Stevenson on 14/01/2021 17:50:49:

The way I get around this is to use a curved slot and a locking screw....not really 'orology', and not really engineering either but it works and you can be reasonably sure it will stay as set.

Bob, thanks for reply can you elaborate a bit so I can understand where the curve slot and screw goes for your remedy/

Chris

14/01/2021 17:43:05

Hi Guys,

This is a piece off a Gustav Becker wall clock. This piece is part of the escapement mechanism. However this clock has a friction washer that pushes the tri pointed brass onto a 9mm Dia piece of brass. The pressure of the spring is there to maintain position but allow adjustment if necessary.

My question is as the pressure from the steel friction spring puts pressure on the 2 brassfriction mechanism.jpg surfaces, the smaller being 9mm Dia is there a way to optimise friction between the 2 brass surfaces whist not actually soldering them together or changing the spring.

Obviously or should I say I think flat smooth brass must have a lower friction rating that rough but making the surfaces rough would reduce contact area.

Optimising friction means the clock is less likely to go out of beat.

I would be grateful for any suggestions on possible solutions.

regards

Chris

Thread: Oil Blackening and other Oil Issues
09/01/2021 11:11:28

Thanks for posts thus far. Anyone that can with the use of rapeseed oil as opposed to petrol type oil would be appreciated.

Chris

09/01/2021 10:16:36

Hi Guys,

I recently made a steel friction pin for a clock. It would have been nice to have protected it from rust and even better to blacken it. The steel was hardened and could not be tempered.

I have heard that you can oil blacken could anyone clarify how and does this temper or not in the process.

Second question relating to oil quenching and hydrocarbons. Petroleum type oil gives off a lethal smoke when quenching metal in confined spaces but is rapeseed oil safe?

can anyone help with advice on these points?

Regards

Chris

Thread: Odd Screw size???
03/01/2021 14:41:52

Done a bit more digging around. Seems there are grades of fit for commercial uses of threads. Then there are sloppy manufacturers. So I revise my previous post which though empirically correct as the 3 screws measured rendering a 7.5% deviation this probably just indicates the sloppy end of manufacturing tolerance available. I guess for most hobby uses fit is not critical but having said that I will be watching out a bit more.

Also if I have say a metric hole I doubt I could easily tell the fit grade that was made to to match an equivalent bolt / screw anyway. If I tapped a new thread what fit grade would that be? Life could get complicated.

What started out to be a simple question of what thread is this in relation to its outer diameter has grown legs. I am happy to say the 3.7 measured is a sloppy fit for a M4 0.7 thread.....poor fit that it obviously is.

Rgards

Chris

03/01/2021 12:13:42
Posted by Howard Lewis on 03/01/2021 11:26:47:

Elsewhere on this Forum, it has been posted that threads are truncated to prevent root/crest interference.

This other post, stated that the truncation for a Metric thread would be 10% of the pitch. So for a 4 x 0.7 the OD would be 4 - 0.14 = 3.86 mm, so your 3.7 is a little undersize. But the thread may be rolled, and so a little undersize anyway.

This will reduce the % engagement, but is unlikely to cause problems. ( If thread strength is important, as in say, yield tightening applications, mass produced rolled threads would probably not be used ).

If it works satisfactorily, why worry? If it ain't broke, don't fix it!

Howard

 

Howard I have just measured 3 unused metric threads (2 fine, 1 coarse) they all work out in terms of measured diameter to be almost exactly 92.5% of the nominal diameter size.

Not saying you are wrong but to date I would question its usefulness. Needless to say different spec on manufacturing will give some inevitable tolerances.

Chris

Edited By Chris TickTock on 03/01/2021 12:13:53

02/01/2021 20:23:33

Thanks Guys,

Lessons learned.

Chris

02/01/2021 18:12:56
Posted by Tony Pratt 1 on 02/01/2021 18:05:52:

It's going to be metric, off the top of my head M4 x .7 pitch???wink

Tony

You beat me to it Tony...well done. I was under the impression that a M$ thread would measure 4mm across its thread, obviously not.

Another lesson learned today

Chris

02/01/2021 18:02:24

Hi Huys,

I have a Katsu jigsaw. The blades are held in with 2 socket head screws marked 8.8 and HDW.

The TPI is I think 38. The outer diameter of this screw is 3.7mm. I have just matched the thread with one of mu gauges, metric 60 degree 0.7. How do I translate that into screw spec?

 

Chris

 

Edited By Chris TickTock on 02/01/2021 18:10:45

Thread: Boring a circular groove
29/12/2020 18:02:21
Posted by JasonB on 29/12/2020 13:09:33:

Chris now we know what you need to do my suggested ball nosed milling cutter would do but if you don't want to buy one then you can actually do it but simply drilling a 2.5mm dia hole right through the cube and then using a standard milling cutter to form the rectangular recess shown on your sketch which will split the round hole in two.

tt cube.jpg

Like it Jason, clever. many thanks.

Chris

29/12/2020 11:35:25

Hi Guys, thanks for posts for clarity the half round groove goes right across the face in a straight line.

Regards

Chris

28/12/2020 15:33:23

Hi Guys,

half circle bore.jpegI intend boring a half round groove of diameter 2.5mm into the bottom of a 15mm mild steel cube. Not sure what tool to use any suggestions welcome.

Regards

Chris

Thread: Help with boring an interior cone
02/11/2020 15:11:19

Thanks guys really interesting. I ended up making a D drill bit and it worked well...to my surprise.

d bit 60degree.jpg

Chris

31/10/2020 17:25:33

hi guys, I have been asking around for ways to make an internal 60 degree cone on 6mm mild steel. Various options are spot drill, chamfer end mill and boring bar. The first 2 options i get but not the third.

As I have done little boring can anyone advise as to bit required and setup on my Sherline lathe.

Regards

Chris

Thread: Suggestions for drilling a v shape
28/10/2020 12:41:18

Thanks Guys for all posts all noted and appreciated.

I am buying in a 90 degrees spot drill which should do the job. Still chewing over using brass bushes which would allow me to use centre drills with various DIA tapers and end holes, but then this would mean making additional parts and possibly introduce errors. I will see how the centre drill does.

If I only had 1 or 2 tapered holes then maybe making a D drill would be the answer. The issue with making a simple jig to hold anything from under 1mm to 5 or 6mm and over a limited depth of 4 mm is limiting on the tools available off the shelf. From my calculations I expect the 90 degree 6mm centre drill will be acceptable...I will see.

Chris

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