Member postings for Fowlers Fury

+1 for Muzzer's comments.

The significant variation in physical properties of HPPs impregnated with materials such as mica, graphite, carbon fibre etc means it's essential to know what is the base HPP and how the additions modify its physico/chemical properties.

As he also implies, production of the HPP itself is hi-tech and distributors will normally just machine the bulk product into saleable sizes. The HPPS, PEEK and PES were developed by ICI and their synthesis is complex e.g.
cpsm.kpi.ua/polymer/1994/2/415-422.pdf
My choice of PEEK CA30 grade was based on readilly available data and key properties such as expansion due to heat and water absorption, thermal stability, creep etc.
Without such data, you're asking for trouble in an untried and unproven application IMHO.

The usage of a high-performance polymer (HPP) like PEEK, impregnated PTFE etc for piston valve bobbins led me to many hours of research.
Expansion is the problem. If you bear with this brief narrative about piston valves, it might aid your thinking about PEEK for slide valves altho' of course the situation is different.
If you machine a HPP bobbin to slide nicely at ambient temp then it WILL seize at steam temperature. Keith Wilson and many others have reported this. Advice is the tedious process of putting the whole casting in the domestic oven set to the temp of the steam your boiler pressure will produce. You are then supposed to keep skimming the bobbins - a thou or two at a time - until they slide at this elevated temp. Well....yes, that's good except that at ambient temp, there's damn-all contact between the bobbin and the piston valve bore. So that means you'll never get the engine to run on compressed air and starting up on steam will also be problematic.
John, you don't write whether your valves are to run on CI or GM. I found that carbon-fibre impregnated PEEK "PEEK CA30" had the best properties in terms of relatively low linear expansion and wear resistance at moderate superheated steam temp. It is not cheap and judging by how quickly it blunts a HSS cutting tool, I'm a bit apprehensive about use on GM surfaces, but it should be OK with CI.
This offers some comparative data:-

I purchased the PEEK CA30 from Davis Ind Palstics and found them very helpful.

Edited By Fowlers Fury on 25/11/2017 17:08:22

"Now here comes what might seem like an exceedingly stupid question."

There is no such thing.

"As well as the pivots in the back plate, will I need to remove the hands & face in order to do the same to the pivots in the front plate?"

I don't want to complicate the answer to that, so.....it depends on how much room there is twixt the plate and dial.

If they have been oiled before and there's insufficient room to put solvent from an artist's brush into all the oiling cups then "yes" you should. It is a straightforward enough procedure.

A careless previous owner may have just dribbled oil down from the top of the front plate so either way (i.e. whether oiled before or not) removal is advisable.

But as before, if you're hesitant then just somehow try applying solvent in situ - if the clock still wont run you'll just have to then remove the dial.

My favourite: "If youth knew how and age were able".

(Trouble is I missed the time when it was optimum for both variables)

(1) "he kept a bucket of horse pee for quenching just about everything that needed quenching"

Including his thirst no doubt.

(2) 'was fascinated by that recent BBC "Handmade" prog where Owen the blacksmith forged the knife:-

**LINK**

At 17.20 he pours some oil(?) into his quenching bath, whether topping up or floating it on the water I couldn't see.

(3) Urine, saltpetre - "Are You Taking The P*ss?"

Interesting read on the etymology here:- **LINK**

"So desperate was the need for potassium nitrate (aka saltpetre) for making gunpowder that when it was discovered that it could be made from urine King Charles I issued a proclamation that families had to collect the urine of their livestock and hand it over to ‘Saltpeter men’ who collected it daily."

But as usual.... a thread is now lacking direction and aim

"Does anyone else have an opinion?" on scaling from full size

LBSC certainly had !

His 5" GWR "Pansy" had Stephenson's and slide valves beneath the cylinders. Since it is a powerful little loco, free running etc, is it worth looking at his valve design, especially the porting ?

Described in Model Engineer Volumes 118–120.

Re. your "It seems a good point to fabricate a mini tube bender" and "mag articles on the subject but I do not subscribe".

You could wose than look at David Carpenter's FREE ! website **LINK**

There have been two designs over the years, the first being **LINK**

But the easier one to build, producing accurate, tight curves in small Cu pipes was published by "Artisan". Unfortunately David seems to have moved the article to a DVD now (requiring payment) but I have the pdf and this image is from that, hopefully not infringing copyright:-

This is mine and have always felt it worth the effort of making in that my pet aversion is seeing poorly-formed bends in wavy pipes on otherwise excellent models.

I freely acknowledge an ignorance of things electric but with reference to my earlier post, Transwave told me that the motor's current consumption was a critical factor - assuming of course that the lathe's bearings were OK.

Accordingly I set the LED readout to show amps and if they get close to 2.6A (taken from the motor's data plate) then I change the belt on the pulleys to prevent the thermal cut-out operating in the middle of machining, invariably at some critical point ! Yet it seems from posts, such as Tony's above, that others don't suffer from this constraint.

On my Myford S7 to keep below the 2.6A, the motor has to be running fairly fast so when needing a slow mandrel speed I'm forever "swopping pulleys". The desk fan helps motor cooling but the set up only permits fairly small changes in motor speed via the pot at any one belt & pulley setting.

Using the kit supplied by Transwave (usual disclaimer but service was 1st class), it's advisable to set the Cub's read-out to amps rather than the default. The motor was a 1hp and prior to purchase Transwave's comment was words to the effect "don't think you can forget about changing the belt/pulleys from now on, you will have to !". The motor will stop by the thermal cut out if more than its stated 2.6A is being consumed so regualr belt changing is still needed to keep below that 2.6A figure (for my motor).

I have a cheap desk fan playing across the motor when in use because being of the enclosed type, its own fan isn't very effective at cooling.

Nevertheless, it is one of the best purchases I've made, especially when using a multi-link Fenner belt to the mandrel on my Myford.

Neil's suggestion about buying the 'proper' press with plastic supports kit is the safest. Choose a plastic base from the selection provided that only contacts the outer, metal part and is not in contact with the crystal.

Also mentioned above is the important point that the backs need to pressed in the centre to a slight degree so that they "dish" before snapping on to the rim. I don't think it will help if you select the plastic 'pusher' which is "full width of back". You will need to exert some considerable force on the handle to get the back on again.

The Omega should have a thin plastic gasket between the back and the case. It's easily damaged. I'd suggest you order a new one first (Fleabay again) as reseating the old one, which will have likely stretched, is nigh on impossible.

If you can get scrounge some clear silicone grease (the "high vacuum" type is best) then smear a tiny amount around the edge of the back. Not only will it help putting the back on but it will provide a better seal.

Brian, firstly apologies the awful diagram below but I musn't disregard copyright by reproducing one from a book.

Furthermore, this will probably incite others' condemnation but with respect to "I dismantle the movement prior to cleaning? " and "I might create more problems than I'm solving. On the other hand, if I don't, it looks like I could be doing damage in the long term if I run it uncleaned". It's perhaps worthwhile offering how pivots are supposed to be installed in a good clock. There should be a concave cut in the outer face where the pivot end emerges. This is to retain clock oil. A broach should then have been used from the other side to produce an tapered hole. The result is that the (hardened) pivot is supported only by a thin plane of the the brass plate..Accordingly there ought to be no "long parallel hole" through which the pivot turns and thus brushing some solvent onto both sides of the plate should (might?) remove any old oxidised oil - shown in red below. Clock mechanisms are pretty robust and "...doing damage in the long term if I run it uncleaned" is very unlikely especially one encased. I would suggest you try the easy way first. As before. you've nothing to lose but half an hour's work.

If you've not completely dismantled and reassembled a clock before, the lengthy process is quite a challenge though rewarding if the clock could not otherwise be made to run.

You ask "......is cleaning the gunk out of the pivot holes with lighter fluid something that can be done without dismantling the movement?"

The answer is - like to most questions - it depends what you mean by...... in this case ~ "cleaning".

The only effective way to thoroughly clean out pivot holes is to dismantle and then repeatedly rotate some sharpened pegwood which has been dipped in a volatile solvent until the pegwood shows no trace of "gunk". (Pegwood is a special soft wood available from suppliers).

However as you'll have read in my & "Roy's" 2nd posts, it's worth trying first without dismantling especially as you've no experience yet of all the inevitable aggravation of a total strip-down to each and every component. You've nothing to lose by experimenting.

The books will tell you there's seldom one simple reason why a clock won't continue to run. Yet my patience was pushed to extremes trying to identify why an English Longcase always stopped after about 30 minutes. I'd done all the cleaning and checking according to the approved methods. Eventually I discovered a tiny burr on one tooth of a brass wheel was the cause.

If you find you've opened Pandora's Box by asking for advice ~ then since you state the clock will run for a couple of minutes then stop, it's possible that "non-clock" oil was once used to lubricate it. Over the "30 years or so" it will have oxidised and gummed up the works. So you'll do no harm if you first remove the clock from the case works and follow Roy's advice but try before dismantling the parts.

Using an artist's brush, flood the holes in the plates where the pivots fit with - as suggested above - lighter fuel (naptha). You might find there is a hole on the 2 spring cases, if so run some solvent in there also. Don't then use any other lubricant. If it still stops after a couple of minutes once you've followed the important advice to ensure an even "tick & tock" then you'll need to investigate further. If you do decide on a full scale dismantling take as many photos of the assembly as you can beforehand.

Nice lookiing Staffordshire by the way !

There'll be no shortage of advice on offer here !

But I'd recommend you get a book on the subject and learn at your own pace. Donald de Carle was one of the best authors IMHO and his old book "Clock & Watch Repairing" should be available on-line. It was first published in 1959, my copy is a 1996 reprint. ISBN 0 7091 9436 6. It's showing now on Amazon:-

**LINK**

Alternatively if you Google "horology course on line free" you will find some useful material.

Your clock should be OK but probably in need of a strip-down and clean. It is of a quite common type.

As for cleaning the face, be very cautious. I'd suggest you try some cotton buds and saliva ! It can be surprisingly effective. Certainly don't use any proprietary metal polishes.

Perhaps someone could identify this one !!

Bit of TLC should see it restored to former glory.........

​(Seen in Isafjordur, Iceland this summer).

Interesting query…. difficult though to really imagine either the “39” or “50” are anything but intentional given the images of other Mora clock faces from that era. But, yes why ??

I’d certainly support the posters who recommend retaining the clock face you have. Is it worth trying to:-

(a) get a valuation on your "unique" Mora face?

(b) obtaining another, but better one ? There seem to be plenty of references to sellers & stockists e.g. **LINK**

[Sorry & no personal offence intended ~ but as much as I like longcase clocks, those 'pregnant belly' Mora clocks have always looked hideous to me]

I should first confess to a late-in-life realisation that Geo.Thomas’ rather pedantic articles on model engineering were actually sound and not as doctrinaire as I had naively thought. It was whilst observing the flexing of my home-made b/bar when machining GM twin cylinders that I looked up his writing on the subject. In terms of the normal, radial b/bar he wrote “..my design attempts to provide a suitable means of advancing the cutter ended in severe weakening of the bar at the point of maximum bending-moment”. I thought that might be the explanation for my non-parallel bores and with only about 10 thou left to machine, I made his angled tool design from a wider silver steel bar which he claimed would not only flex less but also make using a micrometer for measuring tool point radius much easier. It certainly wasn't a five minute job !

I don’t decry the use of 90 deg radial tool b/bars; but merely offer that GT’s design did work much better in my particular case and has produced perfectly parallel bores without a problem many times since.

Brian, may I ask whether you've used a radial tool with a between centres b/bar previously? If you have then presumably you've encountereed the buggeration and calculations needed each time you want to determine how far to advance the tool and then check it's been moved precisely. Even with a tool not protruding from t'other end there's the added difficulty of the open end and how that might affect a micrometer or vernier reading. OK, you could make a smooth surfaced plug but that'd have to be removed and replaced for every measurement. Life is so very much easier with an angle tool as per Geo Thomas and other's designs. However I can appreciate the attractions of just making a radial hole for the tool.

Edited By Fowlers Fury on 27/09/2017 17:21:02

Fully understood Brian and sympathies with the situation.

If you "don't have a great amount of metal to remove" is it worth considering a double-ended tool in your small diameter b/bar to reduce flexing? The tool would obviously have to be ground to o/a length of the precise final diameter.

I've not had to employ the method and can't now find the reference I once had. No doubt others can testify or otherwise as to its effectiveness.

Brian, likewise the bore of the cylinders I was machining had to be 1.5 ± 0.001" and my original b/bar was also 3/4" D. It just wasn't substantial enough, as you acknowledge "not very rigid". The early cuts were causing the bar to flex noticeably - particulalry when entering the bore and thus leading to a 'lip'. The Geo. Thomas one illustrated was 1.25"D and worked very well for those cuts to final, exact size. As he pointed out in his article, the other big advantage of the angled tool is the comparative ease with which you can measure the radius of cut c/f a radial tool where it protrudes below the bar. Perhaps a b/bar of just 50% of the required hole diameter will cause you problems irrespective of tool point geometry?