Member postings for ChrisH

Correction, I meant to say not many IC engines on display, (compared to say the Bristol show). I saw (drooled over!) the Anzani engine and a Bentley rotary engine, but there was not a lot more IC, compared to the number of steam chuff chuffs. The traction engines in steam outside were lovely too. The SBA launch complete with boiler and steam engine was a delight, beautiful installation. One can but dream!

Interestingly, it was less crowded early afternoon - I left just after 3pm - than in the morning. That helped getting to see what was on the stands!!

Chris

Went yesterday, opening day, couldn't believe the number of people there 30 mins after opening time, took nearly 20 mins to do the last 400 yards. No IC engines on view that I saw, but the trade counters were very busy and they were worth the trip on their own. Enjoyed it. Got what I came for, saw what I came to look at. And had a good lunch there too!

Chris

John, I have admired your contributions to this and other forums, always practical, down to earth, basic even and without the non-essential frills. You obviously don't do politically correct or suffer fools gladly, good man. Sound judgement. You would have made an excellent ships engineer back in the day when we still had a merchant navy and I would have been proud to have sailed with you. Wish you all the best and expect to read your continuing contributions on here and elsewhere again very soon.

Cheers,

Chris

PS. Can't believe Ketan still owes you that quid, after all we all on here have spent there, piker................

Jason. I understand what you are saying, a bit like a third way! You confirm the reason for heat treat is to give the 'set' and 'spring'. Making them oversize, cutting the gap and squeezing them down and machining them I guess does the same job.

Do you check the fit of the rings inside the bore against a back light to see if they are fitting 'tight' against the bore all the way round, and if so, do you have to fettle them to fit tight at all? Just wondering how tight a fit this method gives!

Chris

I suppose whether you have the thickness bigger than the width is a bit down to personal inclination and the size of rings you are making. Too narrow a ring and it becomes a bit fraught to handle. The engine I am building specified 0.032" width; I chickened out and up'd that to 0.040" and that still seemed too narrow to me. The pressure of the ring against the cylinder wall is a function of the ring thickness, the thicker it is the greater the pressure in very simplistic terms. You pays yer money and takes yer choice as they say.

What I want to know is why are the rings heat treated during manufacture? I have looked at two methods of making rings, one using heat treatment and one without. Both are very similar methods in certain respects, both make the rings oversize, squeeze them onto a mandrel and then turn to size. The difference is that the heat treated version is made to bore diameter plus a few thou, the rings are stretched apart by about say 0.100 and then heat treated before being squeezed onto the mandrel. In the non heat treat method, the rings are turned a diameter that equates to a circumference made up from the bore diameter circumference plus a 'compression gap'. The compression gap is then cut off and the rings squeezed onto the mandrel for turning to size. The argument for this method is that the rings are turned perfectly round before squeezing; the heat treatment leaves the rings out of round where the gap ends are. Although the rings are then turned true, the argument says, the pressure is now not uniform around the ring unlike the non heat treated rings. I don't know if this is true but it sounds good!

So why are the rings heat treated? Is it to relieve stress, or is it to put a 'set' in the ring to make it spring against the cylinder wall?

Chris

I have been reading ways to make piston rings for IC engines and am getting confused - easily done I know.

Some advocate heat treating the rings with the rings held apart a certain gap to relieve stress, but not too much heat so as to take out all the 'spring', some have a different construction method to get a more round ring giving equal pressure all round the cylinder wall but without heat treatment; some advocate a ring thickness (outside to inside diameter) greater than the width (top to bottom of ring in direction of the bore) and some a greater width than thickness with a minimum width of 45 thou (inch) and a maximum of 60 thou.

Re the latter, in full size experience I have always known rings to have a greater thickness than width, and would lean towards that plus a narrower width would reduce friction, but am prepared to accept it may not apply in model IC engines.

Anyone have any views on all this and have a fool-proof, idiot-proof method of construction of IC Engine Piston Rings to suggest and to be followed by someone new to making piston rings?

Chris

SWMBO indicated, as she sometimes does, that she wanted to be driven to Axminster today by enquiring if I needed anything from Axminster Tools. As it happens I did need one item so off we went. She went off shopping and I went for a browse around Axminster Tools, something I used to really enjoy. But not today; I think they have lost their way.

It had been a while since I had been and they have changed everything around, so nothing was where it was previously or so it seemed; change isn't always a good thing. Lots of big bits of kit, not a lot of what you need to use on or with the kit itself it seemed to me.

So I don't think I shall be going again in a hurry unless they have something I particularly need.

The engineering machinery side was so disappointing, they seem to have tried to go 'upmarket', or at least, more expensive, not necessarily the same thing, at the cost of availability of readily available and affordable lathe and milling tools in particular. The range, of tools for machines not machines themselves, seemed greatly reduced and of very limited selection - where were milling cutters for example - and what there was seemed awfully pricey. Maybe there is a strong market for expensive stuff for folks that can afford it, but it just made me want to look elsewhere for what I need. Sad. Or perhaps it was just me today.

Ho humm, I used to enjoy a browse around their store, but this time I came away quite depressed. I went home and cheered myself up by looking at stuff and prices on the Warco and Arc website, both companies that have served me well in the past, for stuff on the "I want/need list", and then doing a bit in my shed!

Alan - I tried looking for "Taste of the Wild" but it seems like it's only available from Kennelpak in Nottingham? (I'm assuming you are in the UK?) Is that so or is it readily available and how cost effective is it?

Chris

(Not sure if turning CI is worse than sloppy doggy do, both are pretty grim at times)

Many thanks Neil - all is now clear! I must admit also that I did not study the web pages closely. merely skipped through them to look at the drawings - sorry - and so missed the flange. I saw a 9/16" piston reduced to 1/2" for the last 1/32", not the other way round. Your sketch all makes sense of it all now! I do like the concept of this QCTP.

Chris

Well good on you Iain for having the courage of your own convictions. Shall expect to hear great sounds of boasting from your direction in due course,

all the best, Chris

Either something isn't right or I'm reading the drawing wrong Neil!

So another query, piston drawing shows piston at 9/16" diameter reducing to 1/2" at the end, but the toolpost block drawing shows the piston bore at 0.502"? Typo? Or is the piston really 1/2" diameter? Plus the cam is shown as being only 0.510" width, smaller than 9/16" that the piston is shown at - so only the very last 1/32" of the piston will fit on the cam itself as it comes round, the rest sits on the bit of the cam shaft above and below the cam?

I am querying as I am having to enlarge the toolpost block - and probably everything else - as my lathe has a bit bigger toolpost currently. To me I supposed the piston would always sit on the cam whatever position it was in?

Apologies to Iain if I seem to be sidetracking this thread, but if Iain is following this design it will be relevant to him too!

Chris

Many years ago now, newly married, my wife and I were eating lunch when we saw a rat walking across the patio. I had a 410 shotgun, bit of a toy really. so cartridge in and went after ratty. At point blank range blasted him - hollow in soil and rat blown up about a foot. But he carried on walking. Another cartridge, another blast, and another same result. When at the third time of asking ratty continued to walk after being blown sky high I decided it was costing too much in cartridges and fetched a spade. It didn't survive being chopped by a spade!

Another time, went out at dusk and a rat ran off and hid behind a small pile of bricks. Called cat over, showed her where ratty had disappeared and left her to it. Next morning there was ratty, laid out by the back door, brown bread, cat had earned her keep for another day.

Last New Year we had mice coming in our French house. Bought a couple of traps - little nipper types - and over about 10 days caught 7 mice, usually in pairs. Traps worked a treat. Chucked dead mice over the fence into a field - they were always gone by next day so someone was having a feed. Never had mice before, but we always had a cat before, sadly she had passed away aged 16+ years the previous winter.

Edited By ChrisH on 26/09/2017 20:31:58

That's a good endorsement Neil, and add to that - "if it looks right it probably is right". Something else now to add to the "To Do" List! Now to check prices of metal stock!!

Chris

Humm, the 'slippy' bit is food for thought. Thinking out loud - might a MS or hardened piston slip against the cam when under high load and/or vibration from an intermittent cut, or is the diameter of the cam sufficiently large so as to grip whatever? Definitely don't know! (Might be worth a trial.) That has to be set against the possibility a softer material like brass may 'weaken' in a similar high load situation when up hard against the toolholder whereas MS might not? Only pondering! Needs better brains than mine, esp this time of night!

Chris

PS But I prefer the concept of this QCTP compared to the OP one - sorry Iain!

Edited By ChrisH on 25/09/2017 21:41:17

Neil . I have also looked at your plans and it seems well worth a go. I like the simplicity.

But a question Neil, also re the pistons, I see the diameter is 9/16" reducing to 1/2" for the last 1/32" at the back. Why is this? And is it a step down or is it a 'taper' or reduction to provide a sort of bevel, perhaps for when inserting the cam?

And also, why brass, would MS not do as well, or even a hardened cam?

Chris

"A happy customer is a good salesman." A well known customer satisfaction phrase is:

On average a satisfied customer tells 1 (one) other person.

On average, a dissatisfied customer tells 10 (ten) other customers.

Ensuring customer satisfaction should therefore be a priority, a no-brainer, but not all sellers are switched on and savvy!

Personally, I found Tim Stevens' advice to be sound engineering based on experience and training and his last sentence an amusing tongue-in-cheek light hearted conclusion, but maybe I take a less serious view of life, it's too short..........

"Is that not going to change the soil pH and salinity on a fairly perminant basis. So what are the implications for growing things in the future?"

Maybe Martin, but as I do not intend to grow anything on the gravel and slab patio or on the gravel drive which is where I don't want the weeds I don't give a rats. If I was using it on ground I was going to grow stuff in I would just leave out the salt. Best not to use the salt on concrete though I have been told.

And the salt'n'vinegar smell goes very quickly, so smell not a problem, here anyway.

Chris

Not today but a couple of days ago I tried out the 'salt and vinegar' weedkiller method. To my surprise it has worked extremely well and very quickly and all the weeds are dead or rapidly dying, so really pleased.

For those who haven't heard of it, buy 5 litres of whatever strength vinegar your local supermarket stock. Here in France a 5 litre bottle of 10% white vinegar was just 3€, cheap as chips. Dissolve a mug full of fine salt - about 350-400 gms depending on size of mug - in the vinegar and add a tablespoon of washing up liquid - this acts as a surfactant and helps it stick to the weed leaves better. Put into garden sprayer and away you go. Any strength vinegar will work, the stronger the faster. The vinegar kills the weeds, the salt doesn't do the weeds any good either but it also helps stops stuff regrowing on that ground, so the theory goes. I guess that will be a function of how quickly the rain washes the salt away, but resprays will be cheap.

For me the benefits are low cost, an effective weedkiller and a much safer (to me) weedkiller to spray, no need to get all dressed up in massive amounts of PPE, plus it's got to please all the tree hugging greens too presumably, rather than those nasty poisons you buy which I always felt iffy about using!

Chris

Edited By ChrisH on 22/08/2017 10:12:13

Too true Mate!