Member postings for John MC

Alan W2, I would use a parallel interference fit for the shafts with a "top hat" on the end of the shaft, that will stop them moving in the wheels on assembly and in use. The "top hat brim" only needs to stand about 0.1" above the diameter of the shaft and about the same length, counter boring for that will not weaken the flywheels. Make the diameter for the O/D of the brim a clearance so you do not have two fits fighting each other. EN24T would be good for the timing side, the drive side has the drive line shock absorber on it, ideally case hardened EN36 would be best, although I'm sure 24 will be OK for occasional use.

I believe the reason new bearings are so expensive is because the bore of the bearing is ground to a small (0.001"/1.000". My approach would be to look for a modern bearing that the new main shafts could be made to fit and if necessary bore the crankcases to suit the O/D, a spacer would make up any difference in length.

To bore the flywheels I would bolt them together, located from the crank pin hole. A dummy pin may be need to do this. Its vital that this is done accurately, if not the wheels will not true up properly.

Hope these ramblings are useful.

John

OP, are you sure the fit is not the usual Veloce slow taper? Many years ago I repaired a Mk1 KSS crank that had suffered they same as yours. Straight forward turning job, all the diameters can be turned at the same setting ensuring concentricity. What I had to do was bore the holes in the flywheels, both damaged. I bored them just enough to remove the damage and counterbored to take a "head" left on the inner ends of the shafts to stop them pulling through the flywheels. this approach avoids the welding approach. If you do bore the mainshaft holes this must be done with great care, setting up off the crankpin hole, get this wrong and the crank will never true up on assembly.

I believe Alpha are not trading at the moment, hopefully to return soon.

I would disagree with the "aftermarket scene" for post war Velo's being huge. The main supplier is not getting any younger and would like to retire. Anno domini is making itself felt with four other specialists (repairers). Some other classic bike dealers sell the common stuff, the more specialist stuff will become hard to get unless someone picks up the reins, may be the owners club?

Its also been mentioned someone is making complete engines, not quite but I believe that is his ambition. The price will mean that very few will be able to buy these parts.

John

Many years ago I worked in a civil engineering laboratory, at that time I did a number of drawings for house extensions and workshops. One thing that has stayed in my mind is the willingness of the concrete delivery guys to add far too much water to the mix, so they can get it "delivered" quicker. As John McN pointed out, not good to add too much water, weaker, more crack prone concrete will be the result.

To stop this happening I would borrow from the laboratory 6" cube moulds. The look of annoyance on the delivery guys face was plain to see, but it would ensure good concrete. If I was present when the delivery was made and thought the pour didn't look right I would get the cubes tested. pleased I did on a couple of occasions.

The point of my ramblings is to suggest that if at all possible the OP could get hold of a couple of cube moulds, their presence may well ensure that whatever thickness/reinforcement is used, it'll be a goodun'.

John

Many years ago a neighbour wanted to sharpen his cylinder mower. He asked me to drill some holes in a file and remove the tang so he could bolt it in place of the mowers fixed blade. It worked very well, sharpened the cylinder blades once a year for many years.

I have also seen the cylinder blades from a "Dennis" mower sharpened in a lathe by normal turning, the blades not being very hard a HSS tool coped well.

John

Michael G, thanks for the link, interesting. Looks like a "quick fix", the bearing surface must be substantially reduced with a related reduction in life. If the knurled surface is anything like that we might put on, say, a thumbscrew then the oil will have a direct route down the guide, something engine designers and manufacturers go to some length to avoid. This will play havoc with emissions.

I could be wrong, but as I said a quick cheap fix.

John

Samsaranda, that sounded nasty! The previous owner had the front wheel rebuilt but did not have the drum skimmed to true it up, I've done that and turned the linings to fit the drum. I've also rebushed the cam pivot and the bronze bush the brake plate floats on, the bush is "oilite", not PH. bronze. I have also fitted a better brake cable. The result of this is still an inadequate brake for modern conditions.

I have a "British Hub" twin leading shoe brake that I will fit, that should be far better suited to modern road conditions.

John

Cast iron will be fine for the triumph valve guides, as advised, be very careful over the fit. Plenty of advice suggesting using Ph. bronze for valve guides. It is not a suitable material for valve guides, it will eventually suffer from the effects of heat, particularly around the exhaust valve. I think Ph. bronze is confused with Aluminium bronze, both difficult to machine, Al. bronze being far more suitable than Ph, bronze, as is cast iron. Columbia metals do "freecutting" versions of various bronzes, as suggested "Colsibro" (Al. Bronze) being very suited to valve guide usuage.

There is only one bearing in an IC engine that would benefit from being made Ph. bronze, the small end bush, highly loaded, marginal lubrication and runs hot. The Gudgeon (wrist, piston) pin will be very hard, its this combination of material/hardness that works well.

Cold extraction/insertion of bearings in Aluminium housings should be avoided, you might get away with it but what tends to happen is metal will be scraped out of the hole, destroying the size/geometry of the hole, then that hole will need repair.

Peak4, never heard of that process, its not a lining process is it? On larger engines the guides are bored, in situ to take a liner. This process was developed to speed up the repair time, time is money! if the guide is "knurled" then surely oil will leak down the guide, do you have a link to the guy who does this?

I recently bought an Ariel Arrow, specifically a "Sports Arrow" with the gold dummy petrol tank "Golden Arrow" was never a name Ariel used, apparently, but that model seemed to always known as that. Been having a lot of fun with it, I was pleasantly surprised at it's lively performance, pity about the front brake............

The previous owner gave me several files of information, lots of road tests from the classic bike revival period. All have missed the point of the bike, that is to say the ethos behind the design of the bike. Also some real gems, a two stroke engine was chosen because it does not require the accuracy in manufacture of a four stroke. The front brake (known to be poor) doesn't feel very good due to the anti-dive geometry of the front forks!

John

Thanks for the replies. I've tried Tuffsaws and a few other ready made blade suppliers, not interested in selling rolls, I've just ended up with a quote for a new ready made blade. Just reinforces the fact that joining my own is considerably cheaper. For a carbon steel blade i have in the past made blades for about half the price of ready made, not such a big saving for HSS or bi-metal blade but still well worth doing.

I would not fully agree about the machines welder not producing good joins, I have had no problems with the blades I make although a little "tweaking" of the recommended settings is sometimes needed.

My saw came from a large local factory (broken gearbox, straightforward repair). They had in the toolroom a large bandsawing section, mainly Startrite and Doall saws. Small like mine to some very big machines capable of cutting 100mm alloy steel to form press tools. The steel arrived for sawing marked out, a suitable hole drilled if necessary for "internal" cuts, blade joined on the machine as were all other blades. Blade came from huge rolls, something like 500m of blade on each roll!

My Chipmaster has dual dials, takes 400 thou off diameter. While the imperial dial is accurate the metric is not. If I zero the dial in "thous" then the cross slide will consistently return to the zero position, checked with a DTI, zero on the metric scale is inconsistent. Anyone else noticed that? I tend to use the DRO so not a problem, would be nice if it was accurate on both scales.

My Triumph has dual dials fitted, absolutely consistent in both ranges.

John

Does anyone know of a supplier of reasonably priced rolls of bandsaw blades? I have in the past got lucky on Ebay buying unused lengths of blade and using the welder on my Startrite saw to join them. No luck with Ebay for a while and running out of blades! Ideally 1/4" (6mm) wide blades.

Thanks, John.

Reading this thread makes me feel old! Made a Sparey running centre 40+ years ago when the imperial size bearings were cheap and readily available. I asked if I could make it at work during my apprenticeship, it was considered to be a good grinding exercise, so everything hardened and ground. Made it with a 2 Morse taper to suit the lathe I had at that time, sold with that lathe after about 15 years use, still going strong now.

John

Army gallows humour, hope it doesn't offend.

A group of soldiers once told me they did not like the Chinook, why I asked, because, they replied, its an aircraft that can have an accident with itself, Sir.

John

Looking at JasonB's photo, Does fitting the scale to the back of the table reduce movement in the Y direction?

I think its a micro hardness tester, for testing the hardness of specimens that will not take the higher indentation loads from the usual Vickers hardness tester. Thin strip and the like. From memory the loads were in grams for micro hardness and kilograms for macro tester.

John

Thanks for all the suggestions regarding tinplate suppliers. I've looked in to the suppliers mentioned some time ago, KS metals only do small pieces in a very thin gauge. Cliffords have closed. "uktinplate" industry only. The one new supplier to me, Edwards, is promising, waiting on a reply to my inquiry.

It seems that tin is applied by electro methods now, the hot dip being obsolete. I like tinplate for its ease of joining, I've used it for the sheet metal on various models, boiler lagging, water tanks, tender bodies and, in the past, enclosures for my occasional forays into electronics. (I hope Maplins survive, useful range of plastic enclosures stocked) I find the thickness of oil drums too thin, I like a it of thickness to work with!

And thanks Graham W5 for reminding of the thickness grades. How and what was that related to? The remaining small piece I have has XXXXX lightly stamped in one corner.

Paul R, thanks for your offer, I'm 100+ miles away so not practical, unfortunately.

John

Many years ago I was given several sheets of "tin plate", steel coated with tin. The sheets were about 2 feet square and 0.025" thick. The tin appeared to have been applied by dipping rather then electro methods. I have now used up my stock and am looking for a more.

All I have found so far are suppliers of coils for the tin can industry and very thin small sheets electroplated with tin for model making.

Anyone know of a supplier for the tinplate I have described?

Thanks, John

Exactly what I ended up doing. I made the nut plate from gauge plate and hardened it. A spacer ensured that the right length could be cut off with a sharp chisel. 50 8BA x 1/2" reduced to 3/8" plus a few spares done in half an hour!

John

Many thanks for the replies. The root of the problem is not cutting the screw to length but tiding up the cut end so it will screw in to the mating thread. I like the ides of the of a "nut plate" as that will hold the screw while being cut and the end tidied up, unscrewing it through the plate will restore the thread.

Off to the workshop to make a nut plate.

John