Nemett Lynx 15 cc 4 Stroke I/C Petrol Engine

[BaronJ]

Hi Gus,

Do you want a copy of my PWM speed controller circuit ?

 

[gus]

Hi Gus,

Do you want a copy of my PWM speed controller circuit ?

Hi Baron ,

Thanks.

My E-address [email protected].

 

[gus]

Cam cutting will be done this week,now that the prep equipment is all done.
Took a bit of time to retrofit RT and graduated to read degrees on the top disc and handwheel dial. The Centre support took four days to come up and complete. Material came from scrap bin and left-overs. Centre is screw operated to forward and retract.
Now reading Malcom's work description and update with my gurus's work samples and tthread posts.
First trials can happen tomorrow and from there the real crankshaft.

 

[gus]

Cam cutting exercise went smoothly but still a learning curve. Dial gaging to mill cam did not work out. Needle was shaking all over and finally moved around like hour hand. Rigged up a ''Bush Engineered DRO"" which worked. First cam cutting continued.
Second practice run will happen tomorrow and hopefully from there the real steel cams appear.
The retrofitted RT performed well w/o rattling. The DIY Centre Support worked.
Cam Cutting
It is true , you can't teach an old dog new tricks. Malcom's cam cutting with the offset by the degree somehow puzzled me.After biindly following his method ,the cam took shape.

 

[Swifty]

Great going Gus, once you understand what Malcolm is describing, it's easy.

Paul.

 

[Brian Rupnow]

Good stuff, Gus. I was hoping you could get through it okay.---Brian

 

[gus]

Got one good cam with second attempt. Will proceed to cut the steel cams.
The "Bush" aka ''Kampong" DRO just upgraded with "Auto Returm Tension".Will use same for the lathe cross slide for diameter reduction.
The S$3.60 Protractor worked well with the cheapy pointer and white sticker reflector to make easy reading.
Protractor is best versus the Rotary Table degree graduation. Reverse reading is fool proof.

 

[Swifty]

I like the auto return tensioner.

Paul.

 

[gus]

I like the auto return tensioner.

Paul.

Hi Paul,


I am flattered.
Since the dial gage did not work,I was so desperate.A DRO from UK would take a week or two come in and fitting it on another problem.The mini mill is too small for "bells & Whistles".
Am glad the Digital Vernier Caliper worked but I was using my hand to as tensioner and thats dangerous. Did cut one side of the first cam.
Was surprised that the humble rubber band worked.
With the cheap/nasty tensioner,I could move quill by the .01mm easiliy.

Will cut the steel cams out of 15 mm SAE Grade 5 Galvanised Bolt.
It it a must to harden cam??
Hopefully by this Friday, I could get a lot more work done.
Weekend fishing coming!!! Fresh fish and chemical free.

 

[Brian Rupnow]

Gus-I have built 6 i.c. engines before I built the Jaguar, and had never hardened a cam until I built the Jaguar. However, on all my previous cams, the tappet has a roller on it that contacted the cam. the Jaguar and the Lynx have a sliding surface tappet, so yes, both the cam and the tappet should be hardened. It's not difficult. Buy some "01" oil hardening steel, machine it the same as any other steel, (it cuts about the same), and then sand any imperfections out of it. Heat it to cherry red and then dump it into a tin can full of old motor oil. That's all you have to do. This is not a case hardening process, it is a "through hardening process" but hard is hard!!! In fact, it will be so hard that you won't be able to machine it after it is hardened.

 

[Swifty]

You will be putting a lot of work into the cam Gus, so it's probably best to use silver steel and harden it. Brian uses O1, oil hardening, but I prefer to have all my silver steel W1, water hardening. That way there is no mixing up of different types. It's my belief that the W1 is a bit more forgiving if you don't reach the correct temperature, it will always harden a bit. You just have to be a bit careful with sharp internal corners with the W1, the shock of the water quench may cause cracks. I only have a Mapp torch, but this is fine for small components, a small hint to know when you have reached the correct temperature is when you see small bright flakes appear on the red hot surface, this is the structure of the steel changing and it's time to quench.

It may pay to do a small test with your high tensile bolt, just turn up a small part and see if there is enough carbon in it to harden by heating it up red hot and quenching it.

Paul.

 

[gus]

You will be putting a lot of work into the cam Gus, so it's probably best to use silver steel and harden it. Brian uses O1, oil hardening, but I prefer to have all my silver steel W1, water hardening. That way there is no mixing up of different types. It's my belief that the W1 is a bit more forgiving if you don't reach the correct temperature, it will always harden a bit. You just have to be a bit careful with sharp internal corners with the W1, the shock of the water quench may cause cracks. I only have a Mapp torch, but this is fine for small components, a small hint to know when you have reached the correct temperature is when you see small bright flakes appear on the red hot surface, this is the structure of the steel changing and it's time to quench.

It may pay to do a small test with your high tensile bolt, just turn up a small part and see if there is enough carbon in it to harden by heating it up red hot and quenching it.

Paul.

OK .Guru. I forgot i bought 1/2'' Silver Steel while shopping in HongKong.
Just recalled. Used same for the tail stock centre.The machineability was good. Filing down and sanding gave good finish. However will practice cam cutting with the grade 5 bolt and try hardening.
Thanks for the prompt reply.

 

[gus]

Hi Paul and Brian,

Thanks for the good advice.
Up to 2001, I was using electric heat treating furnace and slow/medium/fast quenching oils to heat treat forming rolls,punch and cutters. With all these gone,I am back to very basic heat treatment which I did not pick up. Seen my ''uncles'' heat treating and tempering carbon steel chisels by eye ball and their chisels were the best I ever had.
Will be fun. Will report success and disaster this evening.

 

[gus]

Gus been lying low for 2 weeks ,not doing nothing but trying hard to unravel the black magic art of Cam Cutting on the mill.
After umptheen bad cams,at last today at 12:30 pm the first good cam rolled out.
The brass cams were easily cut at my first attempt though some improvement required.This made me over-confident.
The second/third/fourth were anything but cams.
Was about to throw in the towel and beg Paul Swifty to sent me some of his good cams.
Good lesson learnt. The quill must be sufficiently tightened to prevent
shift up/down and yet permit down feed. Cam cutting on a small mill is tough.

 

[Swifty]

That's great Gus, but if all else failed, I would have sent you the cams milled on the one piece as mine are.

Paul.

 

[gus]

That's great Gus, but if all else failed, I would have sent you the cams milled on the one piece as mine are.

Paul.

Hi Paul.

Much appreciated. Am glad I traced it to the loose quill and others. And also the the very small increments are not to messed with.
The cheapy M.I.C. HSS endmill also help to add on my woes.:hDe: Now using a M.I.C. Tungsten Carbide Endmill and so far so good. Just bought a quality Indianequivalent and not cheap. S$48. To standby. The brand is 'Totem''.
Have you come across same. The last Indian 12mm end mill is still sharp after going thru so many mild steel jobs.

Cam blank done. Will finish this last cam piece.


OK .Vertex Accessories are available. This will make retiree Gus poorer.
No sweat. Just made a bundle. So tool shopping no problem.Heading to Fukuoka,Japan with darling boss for our 43 Anniversary. TokyuHands is a big
spread here and 100 yards from Hotel. Will have to lock up my Visa Cards.

 

[Swifty]

Hi Gus, the name Totem sounds familiar, I must have come across that brand in the past. Have a great time at TokyuHands, it may be best to send your wife elsewhere when you go shopping.

Paul.

 

[gus]

Hi Gus, the name Totem sounds familiar, I must have come across that brand in the past. Have a great time at TokyuHands, it may be best to send your wife elsewhere when you go shopping.

Paul.

Fortunately,TokyuHands has got women's department and in the same complex there are many other chain stores. Its each on his own shopping and we meet at 12 noon for lunch and she is always 1/2 hour late and with ample excuses like ''Gus . I bought this item for you.''' And of course ,she bought her own other items.;D

Hopefully the last cam gets done today.

 

[Swifty]

Gus, all women seem to be the same when it comes to shopping, "look, I bought you some socks", that's to cover up all the things that they have bought themselves.

Paul.

 

[gus]

Gus, all women seem to be the same when it comes to shopping, "look, I bought you some socks", that's to cover up all the things that they have bought themselves.

Paul.

Gus married Nellie 43 years ago and 43 years later,have yet to understand her.;D

OK . Second and last cam done rather fast since having picked up the black magic art of ''cam cutting''. Now reading up to tune and fit tappet valves to cam. How much clearance should I go for w/o getting the valves hammering away just like our old Ford cars?
With the Nemett-Lynx Engine we picked up the skill to DIY piston rings and cam cutting. It is true you can't teach ''old dogs'' new tricks.