Member postings for Graham Williams 11

Have 3 plain nuts and one ball bearing type tightened as much as I can using standard spanner. Scenario 1 is when I make a holding 'jig' to lap a piston. I turn 1 end to usually 15mm perhaps in a 3 jaw, then that end into, usually 15mm collet/chuck, and turn to suit piston and finish for pull rod. Next time I use it perhaps using another chuck and nut there is a degree of run-out, not to much of a problem with a hand held lap. Scenario 2 today was with the liner for a Holly Buddy engine. Turned 1 end down to 16mm this time in 3 jaw then that into collet chuck and turned the diameters leaving extra length for parting off. Put that onto a ER25Stephenson square block held on an angle plate and drilled for transfer ports and cut the exhausts. Back to the lathe and run-out was 1 thou, not as bad as seen previously, so bored the liner at that, came to part off and the run-out clearly showed when blade presented to the liner. Think I'll do some tests as suggested then and keep 1 nut to each chuck which can sometimes be difficult if using mill to drill holes working way up the sizes on multiples of same item but the devil drives.

Cheers

Graham W

First thing I checked, both in the nut and the collet, cleaned anything I found out but still the same.

Graham W

Clocked both types of my ER25 chucks in the lathe and they're all with 1/10th of a thou. ........But if I mix the closing nuts (I have 4) and use another nut to that I used to turn something then I have up to 2thou runout. Did think that they would be interchangeable. What's the general thought on this?

Cheers

Graham W

Just a thought Martin, what would the micrometer gauge you have cost, I've never heard of one I'm afraid. The advice I've had pointed me in this type of instrument as the one routinely used and it is easy to use where all the other gauges I've tried never gave me anything satisfactory and were quite variable in use. Cost to me is also a consideration as Tug says and if I had to guess the Fowler tool would cost more, maybe considerably more, than the Russian tool and it would in my opinion still be subject to my lack of feel.

Cheers

Graham W

All very interesting as the guy in Rowan & Martin's show always said. Tried it out again this afternoon on 2 liners I've made and what I've got is exact repeatable readings on multiple attempts, gauge hand held so it's what I'm going to use from here on in. As to why the Russians went for 4 contact points I have no idea but I've always had a healthy respect for Russian technical products, were they not at the forefront of CMM introduction, they do indeed plough their own furrow and because of a desire for usually Dollars the products are within reach price wise.

Martin, will your Fowlers gauge measure in microns? I'm not a fan of barrel (thimble) measurement for anything needing sub thou measurement for the reason I said previously.

Hello Bob. Got something similar to that but it's graduated in thous as yours and was trying to get the taper in the liner to give 20 -30 microns pinch bottom to top so didn't work for me, no better than an internal mike.

Cheers

Graham W

Hi Kiwi. I/we do use it basically as a comparator but it is capable of measurement, that is what it's designed to do.

All 4 contact points (balls) move and are in contact with a central precision? made tapered spindle. I'll take pictures of a 'probe' and post later and perhaps you can tell me whether the design is superior or not to the 3 point type, which as you say are much more expensive and unless you have a no expense spared approach to model IC engine making putting them outside what is reasonable, in my opinion, to spend, Also I didn't want a micrometer (barrel) type as I wasn't confident in getting repeatable readings as all mikes, again in my opinion, depend a great deal on feel. For example measuring a liner with an ordinary inside mike I can get readings that differ by a thou maybe more taking one reading after another, heavy handed or what but it caused problems for me doing it that way. Also ball and telescopic gauges gave differing results so a decent dial bore gauge, economically priced with micron capability, looks good from here.

Hiya Tug. Don't know about perfect but being able to decide on whether you've got the pinch to a working position looks easier to decide on with this gauge. Never underestimate the Russians on producing good stuff, look farther than a cold war Lada lol. Finished with the AM25's now so sorting material for the Holly Buddy engine, think I'll do the liner first LoL.

Regards

Graham W

Edited By Graham Williams 11 on 22/02/2020 06:37:55

Don't need a setting ring as just trying to find the difference between top and bottom of any liner. Choose 1 of 3 'probes' to suit bore set reading at one end to zero and then measure other to show the difference + or - basically a comparator, if you need a setting ring the guy has all sizes though quite costly. Was told by one who knows that the 4 point was superior and used by all the top combat engine makers (Ukrainian/Russian)and easier to use and so far I've found it easy to use. Was only 100 dollars delivered, they do like dollars, he had others that were cheaper. Searched online after only finding ones that didn't have the required scale and they all looked well used, pricey and used a different system to measure which looked clumsy.

Chuffed today received a Russian 4 point Bore gauge, all the way from Bulgaria of all places, measure down to 2 microns in the range 10 - 18mm which covers all engines I'm likely to have an interest in. No guessing now as to how much pinch I've managed to get when lapping liners. Made a new liner for an AM 25 last few days, gauge saying 25microns pinch so well pleased

Edited By Graham Williams 11 on 21/02/2020 17:51:41

This is the cylinder lap that I used as recommended by John A, Piston lap is similar to that I used Tug but will try John's suggested method with an AM25 piston this time around. Needle valve jet hole was to deep, almost 0.090 past cross holes so will make another one tomorrow.. Wish my drgs looked that good Tug, foolscap and sometimes a ruler is the best I can do LoL

Cheers

Graham W

Hello John, was turned away from going the speedhone route as I was informed that it was impossible to get the required 'pinch' near TDC in the liner using one, do you not bother with trying to get that slight taper or is there a way of doing it using a Delapena type? I have something similar to your second photo, built from a kit supplied by a company near Long Eaton whose name eludes me but it doesn't go down small enough to do these small pistons. Up to now have made a circular hand held external hone to a design I found on the web for each piston which is time consuming, using an Alum split collet type would appear to be much quicker and so bought a mini lathe to do all the lapping on

More pictures would be good.

Cheers

Graham W

John MC. What engines are you making, are they Nalons? if yes MK1 or 2 or something completely different? Been shown a different method to lap how I did my pistons using a hand held external lap with piston mounted in the lathe on a jig for want of another term, the method is more like a split collet held in a 3 jaw chuck of a Hobbymat and adjusted by closing the jaws , piston is held on an old conrod and entered into the collet, engineer who uses this method has done many many performance engines and has a wealth of knowledge so will try this next time around

Thanks Tug, am well chuffed .Will check the relative positions of the jet and cross holes, needle is at 7 deg. taper which is what I've used since reading an article about Gordon Burford, cross holes are smaller than I've made in the past which have been 1mm so thought it may have been that. As to what to do next, will have to be the AM25s, simple engines but I like them. Was also thinking of a FRV such as the Holly Buddy which I have the plans for and even modding the Nalon design with a longer crankshaft and front housing so I can use a sealed (1side) front bearing, sealed ones only available 1/32" wider than original spec.

Looking forward to your tether engine build, hope the plans are coming together well.

Regards

Graham W

Well after 2 new rotors, 2 new rotor pins, 2 liners, 2 cylinder jackets, 2 pistons and 2 prop driver+ collets it runs. Needle is right out so think I need to open out the holes a tad, It's loud, don't know the revs but spinning well on a 9x4.

Tug. When I assembled it initially used liberal amounts of after run oil and am wondering if that was the problem you indicated with your ETA. Thanks for all your input Guys and the merry quips.

Cheers

Graham W

Hello Tug. Did as you suggested and tried an old AM25 with a port prime and it fired up no probs so fuel looks OK. Tried the Nalon again as you suggested and finally got it to fire on a port prime but noticed that fuel or gas? was blowing out the Venturi. So took it apart once again and I think I may have misread the drgs as to rotor layout, ie centre pin and rotor drive hole are on the wrong side, nothing to lose so out comes the Tufnol for another try. John is going to run his eye over it and a Mills that always runs backwards next week so hopefully it'll be fixed. Thanks again for your continued input.

Cheers

Graham W

OK Guys, fuel is 2 maybe 3 year old D2000, again, Missuses car don't run on diesel from the filling station either as she's now found out coz the new one is petrol powered!!! !have got my suspicions about the fuel, nearest supplier of the good???? new stuff is a distance away but do also have the offer of trying some home brew.

Had made another piston to fit the first liner I made out of EN3, consensus was EN1A was better so made one out of that and that's the one in the engine. Depends on feel I know but first piston miked up at 0.56625 and the second (tight) one 0.56655.The lap I made to do the liner had 0.001 taper as near as I can currently measure. Contra-piston was lapped and is a good fit with no perceptible leak round it. In the past how I've tried to set compression is to advance it and rotate engine until contact can be felt near TDC with piston and then back off 1 turn and start from there.

Think I'll rebuild the Velo gearbox for some light relief.

Graham W

Well that's a disappointment Tried all day yesterday to see if I could get the engine to fire.......... nothing. Took it all apart to check if I'd made something wrong but it checked out. Thought the piston fit was a bit tight though as it loaded up the con-rod close to TDC so made another piston 0.0003 smaller (according to my digital mic) which seemed better to rotate easier. Tried again but still no go even on a prime, zilch!. Think it's time to go see John for him to have a look see, if he can't find the problem will have an expensive paperweight LoL.

Graham W

Same here as to engineer merchants Tug, only one left where there used to be 4 and usually it's we don't have it but I can get it in a couple of days. Assembly didn't go well as the rotor and drive peg didn't match. Made the rotor using a template filed up from 3/16" bar marking out the centre to drive peg hole and centre popping for the holes which I thought was cock on. Decided to start again and filed up another template with holes distanced using my DRO on my small mill/drill. When I then mounted the tufnol blank to the template saw then that the holding pin, 2BA, was a really poor fit in the hole (3/16" dia) allowing fhe centre hole to drive hole distance to be off so turned up a complete tight fitting pin in the template. Filed the Tufnol, after turning it to dia and centre hole to drg., and fitted it to the backplate and tried assembly again. You live and learn as this time lined up perfectly and bottom end rotated freely so well chuffed. Decided now that I don't like the fit of the prop driver parts so will re-make them and see how it looks.

Cheers

Graham W

Hello Tug. Gone the tapered needle route as I'm set up for grinding the taper on 1 /16" silver steel, done a few whilst set up as need a new NVA for an AM25, saves making a jig to make to Nalon drg. Hadn't got a 0.8mm drill left, usually drill at 1mm anyway so waltzed off to the local engineers emporium, no 0.8mm to be had so had to settle for 1/32", must be old stock lol. Start to assemble now and see how it goes.

Looking forward to your build on the tether car engine.

Cheers

Graham W