New I/C diesel project – ETA15d-x2

[James BParticipant @jamesb]

Hi Ramon,

 

I always read your posts with interest, although I’m afraid i’m not always very good at actually posting a reply… Its nice to see other peoples approaches / setups – even if not relevant to a particular project at that time, you can often apply an aspect of it or may be useful at a later stage.

 

Like you I don’t belong to any clubs, both for reasons that my time is limited and also my interests lean toward IC engines and road steam, rather than locomotives, so seeing other peoples projects progress is nice.

 

Keep them coming!

 

James

[jomacParticipant @jomac]

Hi, first ADY dont make the Bolaero 18 off the MEN site, unless, like me do a scaled up drawing of the plans, because, I found that the bottom of the piston did not allow enough of an opening when the piston was at TDC, I had to file out sections of the skirt to get the timing right, then It could be just me not reading the plans properly.

Ramon, The engine is a David Anderson Satilite 1cc. After much thought and dilema I did not do as you suggested,and that was to bore out the cylinder first, then do the transfer ports after, cause as the transfer ports are on the inside wall of the cylinder, and the 2.5mm carbide end mill is too short to mill down to 10.28mm, So I brought 2 carbide drills, then drilled down to 10.5mm, followed with the other drill which I had sharpened on the T&C grinder as an end mill. there are two port opposite each other, 2.5mm diameter spaced 1.7mm apart, Then drilled out the cylinder 10.5mm, tried to bore out the hole, but as the only boring tool that would fit was a carbide tipped 3/8″ tool, It seemed to hit hard spots, and was waisting the bore, THINKS???,. found some concrete reinforcing bar, (reo bar) 1/2″ diameter, now reo is tough, and comes in various sizes (the ones with formed spirals and straights) its also cheap ie, free of building sites. DONT!!!! put it straight in the lathe and try to cut off the lumps with an indexable or carbide tipped tool, they shatter, which is not good for unprotected eyes, just use a heavy duty bench grinder or large hand grinder, to get it reasonably smooth, I did that and reduced it to 10mm, plus a further reduction to 9mm for about 50mm long, drill and tapped the end 5mm cap head screw and cross drilled to take a piece of 1/8″ round, formed a knife edge tool shape, with the T&C grinder, Did it work YES!!! I started to bore it out, but only just taking out the waisted section, to start with, followed by finer cuts to get it all smooth, Just to see if it would work, I milled off a section off the other end, down to just above center hight, marked that out to take a very small diamond/trapesium shaped indexable bit, and screwed it down with a 3mm round head bolt.( the hole is 2.95 diameter) so be careful when drilling, The negative angle on my other indexable boring bars varies 5-10 degrees, But the tool bit bit is parrellel to the long axis next time I will leave the end 12mm so that there is a bigger landing for the bit, then take off the rear to give clearance.

They both work, with no chatter or undercutting, reo bar, when cut square also make very strong tool holders, (I have a crowbar 5/8″ round which I cannot bend) and being an old age pensioner they are cheap as.

Sorry to be so long winded, but hope it helps someone out there.

John Holloway.

[Ramon WilsonParticipant @ramonwilson3]

Hi John, I guessed as much (DA Sattelite) from the holes and spacing you described previously – I received my MEN disc last week and first thing I did was check out the extra designs and spotted it in there.

 

Following on from your PM and this post it serves to show that there are always several ways to skin the proverbial feline. It’s how you arrive that matters not so much the means of getting there. I must admit though that using reinforcing bar as you have is certainly thinking ‘outside the envelope’ but again, if it works ……… “Where theres a will” definitely springs to mind here John.

 

I’ve had a very busy garden day today but yesterday I found time to visit my friend Lee and use his blasting cabinet. All the relevant parts are now bead blasted and the result was well worth going Once the pistons are done next week the final parts should not take too long then there’s the anodising and trying this nickel plating on those needle valve parts.

 

Thanks for your comment James, it is difficult to know at times if it serves a purpose but from the odd comment and occasional PMs received I guess it is met with favour most of the time – I’ll ‘hang on in there’ then

 

Regards for now – Ramon

[John CParticipant @johnc47954]

Hi Ramon,

Long time watcher and lurker here – your posts really are very much appreciated no matter what the subject. Please do keep up the good work – I always learn something from reading your submissions.

Best regards,

John

[jomacParticipant @jomac]

Ramon. Hi. First I dips me lid to you, cause my finishes are no where as good as yours. Maybe its because I get impatient and tend to cut off great chunks of swarf, and that does not leave enough metal to machine and file down for a fine finish.

Now, reo bar, Iv’e got two examples on how tough this stuff is, the first is a crow bar I used take with me when fossicking for Saphires, it does not flex as much as my other two good crowbars. The second, is when I made a draw bar for my indexer out of 6mm plain round rod, (which had been left outside for 20 years) and had very little pitting in it, I tried to cut a thread with a non adjustable die, it would not touch it !!!!! so I had to go and buy an adjustable die, and run that up and down a number of times just get a good thread. I have no idea what type of steel is in reo bar (concrete reinforcing rod), maybe some one out there knows ???? I think there is some for of rust inhibitor, combined with other stuff, cause it does not rust much, When I went to up grade my welding tickets, 30 years ago, we had to go to Woolongong, which is 350ks east of Canberra, one of the places we went to was a steel mill, they were running red hot rod through a former, to get the raised spiral on it, it then went past a cooling spray, So is it now forged and heat treated ???? Anyway I now know it makes good boring and other tool holders.

Ramon, I agree with other writers of posts, Why dont you submit your articles to Model engineer, you would make very very good replacement for Nemett ( Malcom Stride).

Thanks John Holloway

PS the weather down here in the Southern Tablelands is brilliant -5 degrees upto 19 degrees, but dont worry it will get colder.!!!

[Ramon WilsonParticipant @ramonwilson3]

Hi all,

The last few days has seen some steady progress so a few more pics but first thanks for the kind words of support John C and also for yours John H. I hasten to stress I do not see myself quite as you do with regard to the magazine after all this (making I/C engines) is still a fairly new area to me however I have been steadily working on an article which is nearing completion so hopefully that news will whet your appetite.

 

Regarding finish John, whilst I do not ‘strive’ to achieve such I do ensure that the last cuts are fine ones and the tools nice and sharp in order to keep tool marks to a minimum. As I have mentioned before I swear by the use of the Garryflex abrasive filled rubber blocks. For those who may be uncertain these are not the abrasive coated sponge rubber blocks seen in DIY stores but solid blocks of rubber with the abrasive running throughout. Four grades from coarse to fine and, when used with a lubricant – I normally use parafin – will produce a silky smooth finish to most metals but particularly so on ally and mild steel. One nice thing about them is that you can shape them with a scalpel or slice quite thin portions off them in order to be able to get into narrow grooves etc.

I don’t know if you have anything similar in Aus but they are readily available over here.

 

This shows the backplates after some further milling around the bolt holes to be more in keeping with the original and fettled with the blocks sufficient ready for bead blasting.

This is how they looked after. As said before I do have acess to a good friends blasting cabinet but this is proving such a good way to finish I’m intent on setting something up myself in coming months.

Other work accomplished is the lapping of the liners and pistons and then the pistons to their respective liners. One home made lap did all three liners to a plug gauge and with lesson learned by trying to rush the pistons on the Racers I made a piston lap before starting

I have made this type previously – the time to make one is definitely worth the effort.

Though it won’t be until final assembly I can be absolutely certain, the piston/liner fits at this stage appear to be much better than the Racers but I’m not counting chickens yet.

Something that may be of use to someone….

The pistons were cross drilled in situ on the lathe using the cross slide drilling attachment. I don’t know how but all three holes were .04 mm out of square to the bore. I must have had the attachment slightly out of square but it was all taken down before I noticed the discrepancy so I’m not sure. Fortunately though, although I had originally intended a 5mm pin I had used 3/16 as I had a good supply of dowels which are ideal for wrist pins. The pistons were set up in the vise and the hole aligned using a 3/16 rod in the drill chuck. A 5mm FC3 cutter then had two flutes ground away then finally a light touch on the wheel to reduce the remaining flute to leave enough for reaming. Used in the drill chuck it worked a treat and the holes all re-aligned

 

 

Whilst there is still quite a bit to be done the end is now in sight. Currently the con-rods are being machined and there are still one or two bits outstanding on the third version but hopefully it won’t be long before theres a certain whiff of ‘diesel’ in the air.

 

Once again thanks for your interest

 

Regards for now – Ramon

 

 

 

[jomacParticipant @jomac]

Ramon Hi. Ron Chernic has a good method for drilling the pistons, first before taking them out of the chuck he scribes a center line on the bottom of the piston, then on a face plate he has scribed a vertical line, he then aligns the piston marks with these on the face plate, lock the piston to the face plate, I did the same, but to align the piston properly, had drilled a small hole on the top edge of the face plate, then put the same drill in the mill chuck, and dropped it down into the previously drilled hole, In theory everthing now lines up. A small amount of Super glue allowed me to even things up before the glue dried, then clamped the piston to the face plate. Quicker to do it than write about it !!!!!!. The other thing is, Contra pistons. in the MEN articles Dave Owen ” 2.5cc Mate” Dave machines the contra piston nearly down to the right diameter, then puts a taper on the INSIDE of the CP parts it off, glues the hollowed out section to stub mandrel, faces of the end, then using a thread die holder, which has a slotted and grooved aluminium lap in it (the tightening screw adjusts the lap in or out), and then laps the CP so that lower half just slips into the top of the bore, the top half is a tight fit, Now because the inside of the CP is tapered, it now gives a very good seal, Using this method you only have to do one ???, not half a dozen miss fits. I did try to find that article in MEN, BUT its not in the Owen files, I think from memory, its refered to in another article, for some other IC engine.

PS there is some good aricles in the COOKIES. and have you finished concreting, I have not, I did me back in when I fell of the small ladder, when I was cutting down trees. Thats my excuse,!!! im’e sticking to it, It gets me out of more work

John Holloway

[Ramon WilsonParticipant @ramonwilson3]

Hi John,

I’m not quite sure I follow this method of Ron’s but will check it out – since getting the MEN disc I’ve had little time to really delve into it.

 

Somewhere previously though, I have read about the internal ‘tapered’ contra piston method and it’s easier fitting. Infact I did have a go at one for the Racers but totally missed the principle of reducing the lower portion to fit leaving the top a push fit as you describe. I couldn’t see the benefit with it all a push fit and having a tapered bore behind to grip on so I went back to the conventional(?) way. I’ll have another go on what ever’s next as I can certainly see it should be a lot easier than getting that exact ‘micro’ fit required for a parallel version

 

That said I have just done the Eta’s CP’s lapping them parallel with the piston lap and held them by turning an expanding mandrel down to a push fit in the reverse bore, removing the screw from the mandrel and letting the spring in the mandrel ‘fingers’ grip the CP. That worked well. The third engine has a composite CP – a fixed outer held captive by the cylinder head and a small inner 10mm dia moveable part which has a hemispherical chamber. This was bored 8mm on the reverse and held on a very slightly tapered mandrel for lapping. Now you’ve said however I can see this would have been a lot easier with a spot of Cyano but would never have thought of using it as a temporary means of holding. I’ll certainly give it a try in the future. I’m assuming slight heat will soon break the bond though a sharp tap should do too as CA is not that strong in shear.

 

Yes the groundworks are complete, not that there was much of it – just getting old and sedentiary. Far too much time in the workshop and not enough exercise (Exercise ?)

according to you know who.

 

Regards – Ramon

 

 

 

Edited By Ramon Wilson on 22/05/2011 23:44:41

[LADmachiningParticipant @ladmachining]

The how-to on how to make the contra-pistons is on Ron’s website under ‘Resources’, ‘FAQ’, then item number 8.

 

If you want to navigate there directly, it is on page 6 of the Weaver construction log.

 

These pages mention an *external* 1 degree inluded angle taper on the contra. The OD is the only place the taper can be cut into when the contra is temporarily fixed to a mandrel by it’s ID.

 

I have used this method exclusively to make contra’s for my Diesel engines, and it hasn’t let me down (other than mistakes on my part).

 

Keep up the excellent work Ramon. On a side note – I nearly made it out to the workshop myself the other day. Will spend some more time out there soon, with a bit of luck – plenty of work to be getting on with out there, that’s for sure.

[Ramon WilsonParticipant @ramonwilson3]

Hi Anthony, You’ll get there, don’t despair too much.

 

Thanks for the reminder. Having reread it, it is the info that inspired me to have ago on the Racers. I must have disposed of the scrapper, well couldn’t find it today, but I recall that I did taper the outside to a 1 degree included angle and also the inside for some reason. I have a feeling I felt the thin wall was giving insufficient pressure for the 19mm bore so went back to the more conventional method. Even then I had to ‘grow’ one of them by heat treat as I over lapped it.

 

I must admit reading what John has said it seems that having the initial part a good slip fit in the bore then bringing out the remainder at an angle seems worth pusuing but I’m still not sure about a wall thickness of 25 to 50 thou

 

What’s the largest bore you have made them for?

 

Con-rods are underway at last but no machining today – swmbo cracking the whip in the garden

 

Regards – Ramon

[jomacParticipant @jomac]

Ramon, just to clarify a few thoughts in my head, First when drilling the pistons, I said that I use a drilled hole in the face plate? That should have read angle bracket, also instead of using a drill to align the bracket, the hole I drilled is big enough to fit a piece of drill rod or similar, that saves on breaking drills. To also get a fairly good center for the drill, I also put a 6″ ruler below the drill, or a tapered piece of hard round bar and, carefuly traverse the mill table back and forth. When the rulers is parrallel to the table, you now have center, use a center drill to start the hole. Secondly the contra pistons I make, have an internal 5-10 taper, some times more, that gives enough meat around the base of the CP, I also try the CP in the bottom of the cylinder, as that should have a taper when they were lapped, the external taper is minimal, just enough to make a good gas tight fit. ie its very hard to push it down, If it looks right, it must be right.!!!!! If they are made properly when you screw the CP down, then release the pressure, one swing of the propeller you should hear the CP make a noise when it hits the adjusting screw.

An idea I saw for making conrods was to go down to your local bicycle repair shop and get some worn out/broken pedals, the good ones are forged aluminium alloy, I have no idea what they are made of ????, but they are tough, being forged, apparently the metal molecules are aligned length wise, which is good for conrods, and make a good bearing surfaces, the best thing is, they are generally free, you find lots of goodies in the scrap bin.

Its getting late at night, Im’e tired, so am I making sense.

John Holloway.

[Ramon WilsonParticipant @ramonwilson3]

Hi John, Me too, I’ve just got carried away about painting and am off for an early(?) night with the new copy of MEB

 

Thought you might like to see these though, made them today, first time I’ve turned conrods so well pleased Bit more later

 

 

Regards – Ramon

 

 

[Ramon WilsonParticipant @ramonwilson3]

What is that phrase about ” Eats shoots and leaves”

 

That should have read ‘first time I’ve turned conrods, so (I’m) well pleased’!

 

To date all the conrods made have been milled. I have fought shy of turning them so far because of the perceived problem of holding them to finish off radiusing the ends – so much so that they were drawn out as rectangular section to be milled instead

However the original Eta engines had turned rods so it was a case of biting the bullet and at least having a go. It proved far more easier than anticipated.

 

First blanks were milled and the holes drilled and reamed in the mill to ensure parallelism. Two were milled square section for subsequent turning and, in case this proved a disaster, three were milled to a rectangular section for milling.

 

Having decided to try turning a form tool was made from gauge plate and hardened but not tempered. The blanks were set up and the ends centred and turned to round section and the tapered shank turned to finished diameters. The form tool was made to be able to cut to finish diameter but leaving a 2mm centre portion that would hopefully be sufficient to hold it for the small end. The plan was to remove this after and finish by hand filing.

This ‘cunning plan’ was foiled though ’cause the end broke off Hmmm.

 

‘Neccessity being the mother’ etc created a split tapered collet to grip the shank and this proved the solution. With a slip of paper in to improve the grip this worked very well and both ends (the big ends were recut to reduce the size slightly) were formed holding by this method.

The ridge was turned with a round nose tool flaring the ball end into the shank.

 

This turned out to be a totally succcessful operation and, using one of the thinner rectanglular blanks a third was made with slightly thicker shank for the S&J version which is in fact correct to prototype. This method was definitely quicker and probably much easier to machine than milling on the rotary table so will definitely be used in the future. A smaller rod may prove more difficult in the collet needs boring and the hole may prove too small but a tapered D bit made at the same setting would easily solve that problem.

The form tools were just milled – the top rake milled first and the radii plunge cut in steps.

 

As aways hope this is of use to someone, now Its time for a clean up and then those Tufnol rotors

 

Regards – Ramon

 

 

 

 

 

[Ramon WilsonParticipant @ramonwilson3]

John, my apologies.

 

Yes I see how are doing the piston holes – I like the idea of finding the centre using a six inch ruler, thats how I set a lathe tool to centre height but never given a thought of doing the same on the mill. Something else learnt, small maybe but useful

 

Thanks for the tip on the bike parts too – I guess you are you refering to the crank arms as opposed to the pedals themselves. I do have some very ‘tough’ high tensile(?) aluminium which I use. I don’t know of it’s actual grade but where it came from it is used for making moulds for blow moulding plastics. It’s lovely to machine and much tougher than HE30. If you try to hacksaw it it work hardens very quickly.

I’ve also bought some HE15 but as yet haven’t tried it but with two Bike shops in town I shall certainly look in to redundant pedals a bit further.

 

Do you take Model Engine Builder? Lovely little radial in the latest issue – the drawings are truly a labour of love. Another project ? no not at this stage one or two more diesels lined up first

 

Regards – Ramon

[Ian S CParticipant @iansc]

I find that I can get off cuts of7075 T651 tooling Plate, this is a high tensile alloy, with a similar strength to steel. I have also used bike pedals, some are better than others.

Ian S C

[jomacParticipant @jomac]

Hi Ramon and others. Iv’e been off the air for more than a week cause my ISP did an upgrade, and stuffed up the connection. So Ron Chernic, MEN, and Dave Fenner both had what looks like the DELIPINA external grinder and hones, Dave in his article on building the Sugden Special, mentioned the Grindall ??? that was an article by Allen Booth that was was in MEW. I asked Dave Clarke Feb 2010 if he could reprint that article, unfortunatly he could not get in touch with Allen Booth, but he did put up the digital MEW on this site, problem!!! I gave him the wrong number, Iv’e got a big gap in MEW around that area, So trolling the net, I found a site by Tom Blough. he built 3 external grinder/hones, he had modified them by adding a knurled, indexable screw, which gives minute adjustments to the tool, it seems a better item than the Delipina and the Grindall. Still on honing, I made an internal hone using 10mm round SS , machined a 3mm deep flat on one end, then Araldited a 4mmX4mm piece off a fine stone that I broken, and was for rubbing off the burrs from the deep grooves of a deep bowl, wood turning tool, these stones used to come in 3 sizes and 4 grades, one of them is 3″ long 1 1/2″ wide 1/4″ at the thick side and tapered down to 1/16″ on the narrow side, VERY fragile, To get it round I mounted the SS in the chuck and then with the Dremel with a 30mm diamond disc in it. mounted on the cross slide, traversed back and forth, and turning the chuck by hand, later switched the lathe on and got the hone round BUT 1mm higher than the SS. It worked????, engine oil, makes a messy sludge, Kero does a better job.

I know this might raise the copyrite bugbear again but is it possible to down load a copy of Allen Booths article.

Its been very cold down here lately, so have not been in the workshop. Bugger!!!!.

John Holloway

[David Clark 13Participant @davidclark13]

Hi There

Let me know which issue and I will put it as the demo issue for a while.

regards David

 

[Ramon WilsonParticipant @ramonwilson3]

Hi John, Not sure I like the thought of all that grinding grit and diamond dust around the lathe. I recently cut the wrist pins in the lathe using a small grinding cut off disc and despite covering the surrounding area with oily rags it still felt as if it managed to get everywhere. That said you obviously got a result which is what matters – are you able to expand the stone in the bore by any means?

 

My attempts at true honing have yet to begin. The Delapena I bought is yet to be set up as having decided I don’t want the mess of honing fluid everywhere I need somewhere to put it – I have cleared an area for an extension but have spent what time I have of late on the engines.

 

I lapped these liners using a home made lap. I have made several of this type over the years and they work extemely well. I’m not sure where I got the idea from but I think it may be a Len Mason design. They’re easy enough to make as long as the solder doesnt creep too far around the inside. I always coat both surfaces with soft pencil lead, leaving a strip for the solder, which seems to act as a barrier well enough.

 

Piece of 1/2 MS for the shaft, head from MS and a piece of thick – 10swg – copper

 

The head is silver soldered to the shaft, drilled and tapped on the centreline of where the copper will fit and one half removed.

 

It is then silver soldered along its leading edge before turning to fit the bore.

 

I use carborundum powders starting at 260 grit up to 1000 mixed with thin oil. Good care taken to the cleaning of parts and lap between each change of grit. Speed about 400 rpm

Pic above is ‘after the event’ all liners having been lapped at this point. The washer is to prevent the liner scuffing on the chuck.

 

For pistons I have made this type of lap which as previously mentioned also works well. Both the pistons and liners had about .025 – .04mm left on for lapping

The long awaited final assembly is approaching fast – all that’s left to do are the cylinder head bolts, the venturi system for the S&J version and finishing off the needle valve parts which were mostly made today.

 

Not long now then

 

I have no idea which MEW the Alan Booth ‘Grindall’ is in John but I do know someone who has every issue. If you can give me an idea of the period you think it was I’ll see if I can find it

 

Hope the above on laps is useful to someone

 

Regards – Ramon

 

Edited By Ramon Wilson on 07/06/2011 22:45:15

[Ramon WilsonParticipant @ramonwilson3]

Hi again,

 

I’ve just received the following PM regarding the lapping post above. As there may be others feeling the same I thought it best to answer here rather than answer directly.

 

It read as copied ………

As ever, I’m following your posts with great interest. I’m afraid this may be a silly question, so I hope you won’t mind me asking you direct rather than ‘in public’. Of course a public answer might help someone else reluctant to ask in the first place!

 

With your lap you say ‘turn to fit the bore’ – how closely? Also, presumably, you don’t expand the lap as you work down the grit sizes.

Finally, how ever did you turn a flat piece of 10 swg copper into such a beautiful cylinder?

 

 

Firstly let me say that which many others have iterated on this Forum before – that is that no question is silly, stupid or otherwise if you don’t know the answer. That’s what makes this forum such an asset – a question answered, no matter how one feels it may be seen, may also answer it for others at a stroke so really, no one should be reluctant to ask.

 

So then … the lap. The copper was annealed first before holding it in a vice against a piece of round bar the same size as the head of the lap ‘mandrel’. The head diameter was turned such that the copper once soldered in place would allow sufficient for cleaning up to the size required. The copper was tapped around the steel re- annealing as required – if I recall correctly about three or four times. It needs to be a good fit on the head of the lap. The gap should be as close as will allow access for silver soldering. It can be improved by running a milling cutter through it holding it endwise in the vise of course.

 

The copper can be held in place on the mandrel head by a screw in the adjusting screw hole but make sure this screw is well carboned up as if this gets silversoldered in then its start again time. Once the soldering op is complete the cut off half is inserted into the lap and the adjusting screw set in so that it is just exerting pressure on the copper. Set in the lathe this is then turned using a very sharp tool. Please note however if the silver soldered edge is not the ‘leading’ one then you will very quickly unwind the copper

 

The size to aim for is such that it will just enter freely the bore. If the bore is slightly tapered then it should just do so at the narrow end.

The lap is not charged by rolling in abrasive powder on a hard surface – rather the powder, mixed with light oil, is applied to lap and liner and the liner pushed over the lap. It should be a tight but not overly so fit. Start up the lathe -around 400 rpm – grasping the liner which should allow the lap to revolve with a reasonable drag – if it is difficult to hold against rotation or gets hot then stop, back off the adjusting screw and repeat. Parafin and light oil at about 10:1 makes an ideal lubricant. It gets messy so cover the lathe and wear gloves if you don’t want black hands – really black on cast iron

The lap is fully adjustable by increasing pressure on the inserted floating half of the head via the grub screw and whilst the expansion is not fully radial it does remain round and will true a slightly out of round bore. If the liner is tapered to begin with the taper can be taken out by dwelling in the tight area more but we are talking tapers of tenths here not thous. Conversely putting in a desired taper is done the same but ‘opposite’ way. Providing the adjusting screw location is on the centreline of the length of the copper the lap expands parallel.

This is the lap after the initial lapping of all three cylinders using 260 grit. It is important to thoroughly clean lap and part before going to the next grit. If the surface finish from the tool is good then you should be able to begin with 400-600 grit. I began as such but had left too much on so reverted to the 260 to remove the initial amount quickly.

Something I did overlook to mention before was that these laps are not ‘specific’ in that within the amount of copper left they can

Edited By Ramon Wilson on 08/06/2011 23:01:33

[Ramon WilsonParticipant @ramonwilson3]

 

Something I did overlook to mention before was that these laps are not ‘specific’ in that within the amount of copper left they can be further turned to suit smaller bores.

Well XXXX (‘name withheld to protect the innocent’ ) I hope that helps to answer your questions and of course anyone else I may have confused. I would just like to emphasise this is very definitely not the way to go about it, merely the way I have tackled it — and they’ve got to run yet!

 

As always hope that’s useful

 

Regards – Ramon

 

 

Edited By Ramon Wilson on 08/06/2011 22:34:42

[David Clark 13Participant @davidclark13]

Hi Ramon

How about an article on making the laps.

For Model Engineer.

regards David

[Ramon WilsonParticipant @ramonwilson3]

Hi David,

PM sent

Regards – Ramon

[Bill StarlingParticipant @billstarling10428]

As the ‘protected
innocent’ mentioned by Ramon, I feel suitably chastised for not
coming straight out and asking my question openly. So – publicly –
thanks for a superbly detailed and helpful answer. It has been ‘cut
and pasted’ into my ‘Tips from the ME forum’ file, which is growing
steadily.

[jomacParticipant @jomac]

Ramon Hi. Thats a great idea for an internal hone/lap, I sometimes start to lap with valve grinding paste, just to get the lathe tool marks out, (over exuberance and no patience) I have got 12 tubes of diamond paste, they cost about A$9, so they are much cheaper now than years ago, then finish with Brasso. The internal hone that I tried with SS rod and a fine stone, I should have said that the length of the actual stone is about 35mm long, that way there is less chance of distortion, as it wears more evenly, I have got two slate oil stones which are at least a 100 years old, so I aint cutting those up, so I might get a slate tile and see how that goes. over in the UK just wait for a wind storm you should have plenty???? I think in a previous post. that I do what Dave Owens does and use a thread die holder, to hold a slotted and grooved piece of round Aluminium, that makes it adjustable. Anyway a Gindall or a Delapina is a better option, especialy the one by Tom Blough..

I have a small roll of cling wrap that I got from the butcher/greencrocer, its wider and a bit thicker than domestic stuff, CHEAP if you ask the butcher nicely ie FREE. Providing you dont have to traverse the saddle very far, it some times sticks to the lathe bed, and also wrap it clock around the chuck, it keeps most of the rubbish out of the moving parts, the grit also sticks to it. PLEASE be careful with things spinning on a revolving part. then just screw it up when you have finished, and give the lathe a wipe with an oily rag. works for me!!!!

Now, the Allen Booths article on the external hone that was mentioned by Dave Fenner, in his article on the Sugden Special. At the present this time I cannot get to my MEW mags, but I think its somewhere in the 90s (I am also having trouble getting the on line index to work as well) maybe someone out there has a better memory than me, can help.

I apologise for my spelling and grammer, as I can only type with two fingers and have to look at the keyboard to do that!!!!, just hope it makes sense????

John Holloway

[Ramon WilsonParticipant @ramonwilson3]

No need to apologise John it all makes perfect sense. I can’t type without looking at the keyboard either which makes for some interesting typos I can tell you

 

I have diamond paste too but if it is used on ‘soft’ materials it can inbed itself in to the surface of the metal despite being well cleaned. I guess that would make for some interesting lapping when the engine first fires up. My understanding of it is that you really need an ultrasonic cleaner in order to clean the parts before assembly.

So far I have only used carborundum and on occasion finished off with crocus powder. Recently I was given a very small drop of ‘Diamantine’ a white powder which gives a super high finish but which apparently does not imbed itself but I have as yet to use it.

 

I’ve had a reasonable couple of days making the needle valve assemblies and this has incurred a couple of small techniques which some may find useful.

 

The needles are made from 16swg piano wire. The initial point is ground by hand on the off hand grinder holding it at a shallow angle to the side of the wheel. It’s then held in the lathe and the very tip supported by a piece of hard wood set such that the top surface is just above the centreline. The wood is brought up to the needle so that it penetrates 2-3mm and then using a smooth file the wood is filed through and the taper smoothed and brought true. This works surprisingly well – it’s also a good way of supporting a slender shaft if theres need to reduce it slightly by filing.

The piano wire is a couple of thou larger than the nearest drill size so a piece was cut off and tapered, again by hand on the off hand grinder to a very shallow angle on one side only. (It’s neccessary to keep this cool and not lose the temper by overheating)The burss are smoothed away with a small oilstone then this is held in the drill chuck and used as a reamer. It works extremely well but it is important to constantly remove it to clear the swarf. If this is not done it will quickly build up and backup in the taper to wedge itself well and truly – please, don’t ask

These are for the Mks 1 and 2. The S&J version is from ali and steel and is as yet to be made.The screw thread on the lower needle is 7BA studding drilled and reamed as above and Loctited on. These are the parts that are intended for nickel plating

 

The last items are the spring ratchets for the MK2 and the S&J and these were made by clamping a piece of .2mm planished spring steel and some springy phosy bronze strip between two pieces of mild steel. Despite the tight bolting, the cutting forces – particularly noticeable as the two thin layers of bronze work hardened despite a sharp cutter – still forced burrs between the layers of the shims.

 

Fortunately only one of each is required

The phosy bronze is actually silver plated hence the colour – does any one know how to turn it black ?

As usual – hope this of interest to someone

Off to my old works tomorrow to get some steel for the cylinder bolts – next week should see the final parts bite the dust then.

 

Regards Ramon

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