Member postings for Graham Williams 11

Just a quick question. Made all the parts for the Nalon (though piston might need a nats nuts more taken off as think it's a bit tight) and have now to finish off the NVA. What's the thoughts on that as per drg with a 0.016 cut across it at an angle with a blunt needle or, as I normally make, a cross drilled 0.040 hole with a tapered needle, any advantage either way?

Cheers

Graham W

Tug, both liners have the ports cut, my drg, as Jason's, shows to use a 1" x3/32" slitting saw plunged to 0.134" deep. Managed to find the right size saw at Castle Hardware? in Sheffield, last one they had and made both liners using that, hope the drg is right or it'll mean starting over.

Cheers

Graham W

Tug. Have been fascinated by the amount of information/comment that has been generated and have no problem that a 'slight' deviation to my post has happened, live and learn I say but one thing I'm in awe of is the amount of skill/knowledge displayed by those using the forum, I'm moving along slowly now as made two off cylinder jackets using 2 different methods so getting there. Also sourced another mini lathe at last so I can get on with the lapping though have to make the laps as yet.

Power to your elbow I say.

Cheers

Graham W

Reading all these latest posts, particularly on hi-po engines it comes to mind what sort/class of machinery is being used.......... are they outside the normal 'run of the mill' used by the what I believe is the majority of model makers?

On the UK Combat fliers FB page there is a modern combat engine ( think 20-23K rpm), probably Ukraine in origin, shown in all its glory and no spacer or circlip, what I would call ordinary design, should expect the Viper to be an order of magnitude less in the RPM range! If mine runs and starts easily will be well chuffed as I'm not a trained toolmaker/engineer and it is a complicated engine compared with what I've made before.

Cheers

Graham W

Blimey, I only asked about suitable alum spec lol. but greatful for all the knowledgable input. Hadn't twigged any issue with crank to rear bearing, note to self, read drgs more thoroughly, but believe it's something that I can do fairly easily. The 'photos from the MEN site are of a Mk 2 whose cylinder/head were much different to the Mk1, Drgs and 'photos show csk slotted screws as Jason points out but I've managed to get both cheese head and cap screws of the right length in 6BA for my Mk1, will probably use the allen pins as they match the front and rear housing screws which I have quite a few of.

Cheers

Graham W

OK Tug, thanks once again. Will measure up again when I'm back in the W/Shop tomorrow and bring it to less than a thou under bearings od. and go from there.

Cheers

Graham W

Can only agree Tug, they do look very nice indeed, slightly green with envy as never have taken anything other than one of my bikes to that level of finish, sort of old East German functionality not Victorian splendour is how things end up for me. As to bearing fit I go with how a lot of bike bearings in gearboxes and in crankcases are usually fitted, undersize by 1.1/2thou ish, warm the casting and chill the bearing and drop them in, hope it works on this engine, we'll see.

Cheers

Graham W.

Hello Bill. Made up a bill of materials for the engine and sourced from that, as you say the drgs are saying 1.75" so will have to search again for the correct length cap screws or stick with cheese head if unobtainable.

Oz was a good market for Velos and there's a thriving club, only got one Velo left now, foolishly I sold the other 5 some time ago when space became a problem, which was a big mistake, should have extended the garage, foresight valuable, hindsight not....... o well.

Made my needle valve standard with cross drilled 1mm holes as that's how I've made them before but if that doesn't pan out will make as per drg, which at least means there's no need to grind a taper on the needle.

Cheers

Graham W

Hello Tug. Like you it's the dust off cast iron that gets on my chest no matter what mask I seem to use, might have to go the NBC route lol. You got the guy in one, a thoroughly nice bloke, willing to help in any way he can, one thing he did say which hit home was that it's not easy to get the fit at first, success rate he said was 1 in 10 when he started many moons ago and perseverance is the name of the game until you finally get what's needed, Seems AM25 are in abundance as I now have 3 to re-bore and 2 NVAs to make. Started on the Nalon piston, inside and outside turned and set up to cross drill for the wrist pin, but can feel the dust already so switched to polishing the Velo for a while. LoL.

Cheers

Graham W

Hello Tug. You're right about the washers, they do look somewhat awkward so will dispense with those in due course. Have some 3mm cap screws but haven't tapped the c/case as they look clumsy as well so just ordered up some 2" long steel cheese head in 6BA so will shorten those and use them instead as you suggest. Bill Pudney in OZ suggested the EN1A/cast combination which appealed to me more as, you've probably guessed, I don't like machining cast iron . As to using the Myford for lapping, a very experienced flyer/engine reconditioner on the Barton site, who lives not far from me, kindly showed me his approach to liner/piston fits, he kept the lapping separate to his lathe, a Myford copy, using an old Hobbymat, which obviated the need to have lapping medium near his main machine. If I can get a tired mini lathe, which isn't proving easy, as all on offer seemed to be described as pristine!!!!! I'll set up for doing it that way as I've picked up some worn engines at boot sales again as well, otherwise I'll have to bite the bullet and cover everything in clingfilm and use the Myford

Fingers crossed it'll run, if it's ok have enough material to build a second one, (using the other liner) and it should be quicker as I now have a number of fixtures to machine the various parts lol.

Regards

Graham W

Picked up again after doing some work on my Velocette. Made the rotor, backplate and needle valve and the liner. Made the first liner from what I thought was EN1 but was tougher to machine so made another from known EN1A which machined more easily, also machined it in a slightly different order, both turned out OK, left the bore 1 1/2 thou undersize ready for lapping. Plans show cast iron for the liner but advice was to use mild steel which I must prefer as it's not dirty to machine though the pistons will have to be cast iron, Will need to source a 'tired' mini lathe to do the lapping in as I've decided not to use the Myford for that job.

Finish turning the crankshaft up today then rear housing next, doing the less difficult bits first.

Edited By Graham Williams 11 on 29/10/2019 18:44:00

Used the wrong term they're not studs, drg showing cap screws to hold down the cylinder etc so might now go to 6BA cheese head bolts/screws as nothing else comes up in searching for the needed length.

progress so far on the engine. been searching for 6ba cylinder holdown studs but nothing at length needed (1 3/4" so most likely use 3mm.

Bill. As you've made a couple of Vipers could I ask whether you used a press in crank pin or machined it from the solid, also Ron Chernich's description gives a hard chromed, presumably press fitted, crank pin size of 7/32" dia but the drawings I have show 3/16" dia.and con rod to suit. Also you've used EN1A equivalent for the liner, I was going to follow the drawings which show cast iron but it's a dirty metal, and steel would be better from the point of view of keeping my lathe 'cleaner' .

Cheers

Graham W.

Hello Tug. Been an admirer of your work for ages, I'm sure your Viper will be superb as all the others. 6082 is what I'm using now it does machine nicely so with the views posted here I'm sure that it'll work out ok. Not destined for a model it's just an excercise to keep me active since I retired, refurbed a few engines and made a BollAero which is now running and when I saw the plans for the Nalon reminded me of the Mk 1 ETA15d I used in FAI power models in my younger days. If it runs then I'll be happy though usually to get the fit of the liner/piston/contra correct it takes a few goes, still learning about the lapping process though I've had some excellent advice and a demo on the methods used from a really knowledgeable guy who lives quite close to me. We'll see how it goes and if it's a success will move on to another one that takes my fancy from the MB book.

Cheers

Graham W

6061 was a no go with the local high spec supplier so picked up an offcut of 6082 sufficient to make 2 crankcases at an affordable price so going with that for the rest of the engine. Seems more interest in the Nalon in recent years than there was when it was designed lol.

Thanks everyone for your input.

Cheers

GW

Westway Oils in Wombourne are very competatively priced and supply in 1 and 5litre in both specs, I'm close to them so collect when needed but they do sell on Ebay/ No connection to them just happy with items and service/

Cheers

GW

Material specs and applications can be a minefield for the home machinist. The Viper was designed and sorta developed by one Norman Long in this country. He was involved after the war I believe in the company making YULON engines in Birmingham so not American though the drg spec is 6061 TO43 or 2024 and 2130 steel for the crank (will use EN24T) which I think are American specs. Will try Aalco tomorrow and see what their response is, if it's what I expect, will go as you suggest and use 6082, HE15 is just to expensive and I only use it for con-rods as Jason says.

Cheers

GW