Member postings for Tim Stevens

Borax can also be used when gold soldering. And it is useful stuff whenever you need to make a casting of brass (or silver, or gold ...) And it does not go off if kept in a dry tin.

Cheers, Tim

Clockmakers and jewellers tend to use the term 'broach' for what we might call a reamer (of a particular type). They are five sided, hard steel and slightly tapered, and you use them as you would a conventional reamer. The edges where the ground flats meet are sharp enough to scrape a brass hole, and they are available from jewellers supply firms. I have used them to make unavailable carburettor jets.

Try this for an example:

https://www.ebay.co.uk/itm/A-Pair-of-Very-Fine-Tapered-Hand-Reamers-1-6-1-7mm-diameter-1-16/392460023495?hash=item5b6070b6c7:g:wwgAAOSw~AFdlOle

Regards - Tim 

Edited By Tim Stevens on 20/01/2020 17:41:19

You might get more sense in terms of what the dimensions are, and what fits what, etc by going to a 'bearing supplier' (at least, in the UK). I have had good service from Bearing Boys, and Simply Bearings, and yes, they do pulleys and belts, and all sorts of useful stuff, not just bearings.

Cheers, Tim

A photo is worth 1000 guesses. So, we are left with a cable that might be wrongly routed, or non-standard control lever assemblies, or wider than standard handlebars, or forks fitted too low in the yokes, or the wrong fork tubes (too long - any of which might have been a mistake by a previous owner). Fork tubes are the most likely replacements after an accident caused by eg brakes not working.

Do you know of another similar model in your area, to compare with?

And do please check, because any change in the wheel position will affect the steering, as well as the fit of the cables.

Honda used the same or very similar forks and brake drums on a wide range of models, go-to-work road bikes, trail bikes, motocross machines, etc, and a wander round a second-hand bike showrom could well produce similar models with cables just that bit longer - then you know what to ask for. And it is not difficult for an experienced mechanic to make up a cable to whatever length as a last resort. Just make sure that you get the result properly tested so the nipples don't pull off.

Cheers, Tim

PS by fork tubes I mean the chrome steel parts, not the aluminium alloy ones.

Edited By Tim Stevens on 20/01/2020 17:23:08

Duplicate post

Edited By Tim Stevens on 20/01/2020 16:09:15

My money from the one photo is that the backplate is not located correctly in the fork. yes, I agree with others who have said this. Leave it wrong and the brake may not work properly at all, or the plate may rotate, destroying itself, the cable, and the speedo cable (which should also be checked - if this seems too short then my suggestion is really the problem.)

Why should I know? - a silver medal inm motorcycle engineering. not that I'm boasting or anything - and working for BSA, Norton, and Hesketh.

Cheers, Tim

Have you considered making progressive rate springs? Perhaps by changing the feed angle like you show on the ends, but gradually through the whole length. Otherwise, vary the radius. The results can be useful where you want a soft spring to start with, but stiffer as more load is applied - car suspension is an example.

Et - joyeux Noel a tout le monde

Tim

The problem you may face with a 'dead hard' bolt (pin, etc) is that extreme hardness comes at the expense of toughness. So, a firm tap with a decent hard-faced hammer is likely to knock the head clean off - rather defeating the excercise, I suspect. That is, if you could solve the problem of hardening the head while keeping the threads from being equally fragile. Or distorted.

Sometimes there is a good reason for not being able to find a novel part.

Sorry - Tim

Sorry - system overload, I think, so it arrived twice.

Regards, Tim

Edited By Tim Stevens on 30/12/2019 18:33:38

How much do you know already about the relationships between hardness, tensile strength, fatigue resistance, etc, under different conditions (such as annealed, normalised, fully hardened, etc) in relation to the various steel recipes? M2 is a steel designation, in the USA (and so, lots of places too), and H5 is a tolerance system for holes and spindles etc, but there is a long explanation for each of these terms.

Do you have access to any engineering reference books (such as Machinery's Handbook - there are others) where some of the terms will be explained? Or have you considered reference to Wikipedia, for example? And how well up are you in the world of metallurgy?

Sorry, but until we know quite a lot about your existing understanding, any explanation is likely - at one extreme - to be completely over the top, or so elementary as to be offensively patronising at the other.

Looking forward to a summary of how deep you have got, so far.

Regards, Tim

Just let mum find out, and come to her own deal with the culprit. But don't whatever you do let on that i suggested it.

Cheers, Tim

You might also find good spring material in a (used) seat-belt system. The bit that bolts to the car floor will have a long clock-type spring inside, about 10mm wide. Not much demand for used seat belts, either so finding one should be easy.

Cheers, Tim

The only advantages I can see from the hollow inside are:

1. Cheaper to post

2. Handy for knocking rivets right through - as long as they are short enough to fall into the space.

But -

3. more expensive to make and, I expect, to harden (although only the surface needs it for most jobs).

And I can see the benefit of a square version ... ?

Regards, Tim

If the back (non-V) side was as flat and hard as the front, it would be easy to flip the block if the smaller holes were needed without the groove getting in the way. Just in case you are thinking of going round again, Ketan.

And a jolly yule with plenty of wassail - Tim

Did Neil mean limed oak (and not lined) perhaps? It would make sense as the lime would tend to counteract the remaining acid.

And I have had good results with MDF - which works best when oiled (with anything to hand) to keep the dust in check.

Tim

If you are likely to get into this sort of repair in a regular fashion, you might look at the range of silver-solder colours. CUP would be a start, perhaps. The lower silver content (which brings the price down) tend to be more brass coloured. But that said, they don't always mellow the same as brass as the patina takes hold - so you might rediscover your repairs in 30 years time ...

Enjoy Yule

Tim

If you look at the examples in Michael Gilligan's link, you will see that the first is an involute gear (tables on the right side) with the pressure angle specified, while the third example is cycloid and the area in the table is grey. This is because cycloid gears are created by a different method and the actual pressure angle (and some other details) can vary depending on which bit of the tooth you are looking at.

It does not seem to be clear why clock makers use cycloid gears, - I suspect that tradition, and inheriting a box of old cutters, are both good reasons. It may also be that as the pivots wear - a likely outcome in a 50 year old clock never cleaned or oiled - that a cycloid design is more tolerant of the extra slack.

Hope this helps - Tim

Dave T - yes, I think you were well advised. You now have a local contact whom you might be able to help in return, and you have avoided a long delay in the post (over Xmas, remember) in which stuff gets lost, and if it arrives, is the wrong size, the wrong width, or the wrong keyway.

Didn't we all join this forum as a mutual aid system, not a 'order another and hope' system?

Cheers, and enjoy a festive yule.

Tim

A bearing housing will expand when hot - outwards - and exactly as much as it would if it were solid metal. As it does so, the steel bearing (or shaft) becomes a looser fit in the aluminium, and this means that the area of contact reduces slightly. So slightly, I suggest, that the effect of heat and the stesses from torque and combustion on all the other bits make the effect of minor importance. It is not, afterall, as though your model is going to be required to fly the Atlantic non-stop, is it?

Cheers, Tim

Edited By Tim Stevens on 15/12/2019 17:45:38

On a different tack - it is not clear (or I missed it) how you will be heating the furnace. If you are using gas - perhaps with a big torch - You need to sort out the ventilation of the inner space. Get this wrong and the flame will not get enough air, and will go out. Supply too much air or allow too clear an exit and most of the heat will escape.

If you have an electric heat source, this problem does not arise, of course.

For the liner blocks, you might find it helpful to seek out suppliers of wood-burning stoves (which have linings, of course).

Regards, Tim