Member postings for jomac

Hi. When I was an engraver, we used to fill the etched out area ( name plates etc) with a hard coloured wax, when the plate was heated we rubbed the wax sticks over the area and while it was still warm rubbed/brushed off the excess. To get a very nice finish, just reheated the area only enough to smooth out the wax which finished with a medium to high gloss. the plates could then be polished and then varnished. Doing the graduation marks on a graduation dial works the same. If a hard wax is not available, try using a black candle or any other colour that looks ok. The beauty of this system is that you can melt out the offending wax on low heat, and start again, without damaging your finished , prized piece of turning. At the moment I just use a black marking pen, and when its dry rub off and polish the dials.

PS Its nice to see that 99.9 per cent of all contributers to this forum, have good sense and even better manners, although a bit of tongue in cheek commentary brings out the smiles.

Thanks for all the good info.

John Holloway

Hi i read all the posts on the tangental tool holder, and because Im'e like a lot of you, I cannot afford to spend much money on tooling, So I make my own. First I cut a piece of 16mm cold rolled square 110mm long, Cut a piece of 10mmX50mm flat steel. Put the flat, length wise in the tilting vice, at 45degrees used an 8mm end mill and cut a groove a little less than half the diagonal measurement, the center of the cut about 6mm from the edge Then cut the oblong into two sections. One of these I ground a 15 degree angle at the rear end of this, so that it was pointing to the left, ie, towards the chuck when it was mounted in the tool holder, then ground a 12 degree angle onto the front edge of the 16mm square, then clamped the flat section so that the groove was at the front and the top of this was flush with top of the 16mm, I also ground a deep chamfer on the edges I was going to weld together. I know this sounds difficult, its not, what is, is doing it by your self without proper clamps, or a second pair of hands, anyway you only need a small tack weld to start with, that way you can bend it into the right position. fully weld it togther when you are happy with the position. Clean up the welds The reason I offset the tool only 15degrees, was that it gave me more clearance. Next I put a spotweld at the rear of the second piece of steel,(to act as a pivot point) I put a 1/4 inch HSS in postion and drilled as close to the HSS to tap for a 6mm round head bolt, and clear drilled the welded one, plus recessed to half cover the head, Bolted it together and with the HSS below the marks, cut and ground off the exess, without weakening the welds.

I made a sharpening jig out of timber and, the same as in the model engineer article, it works OK, I also made one out of 12mm steel, milling a slot upwards 12 degrees and angled about 22 degrees, That work too, The timber jig is good for grinding 1/4 round HSS,

Now the big question is does it work, YES. gives a good finish with both bits, BUT if I made another one, I would use two locking bolts, as when taking very heavy cuts the tool bit gets pushed down and below the the work piece,( I had to use a lot of strength to get it to lock up properly).

I tried various angles of attack for the tool bit, to arrive at a reasonable result. You might do better. because I also added a 3 degree angle, to give clearance, It might not need it ?????.

Good luck.

John Holloway.

Robert.Hi. Iv'e got an Australian HERCUS 260, which is the 5' model. Its much more modern than the earlier 4.5', which is very similar to the South Bend, but they still use the same gears for the gear train, The problem I had, was, that I needed a full set of gears. So that I could cut imperial on a metric lathe. So as mentioned in previous threads, I used a 63/64 combination, The two used machinery places I went to, had lots of gear for Hercus Boxford, and Colchester, I did not have a gear tooth gauge with me at the time, BUT the Boxford gears looked different. ie, different DP/PA, The Hercus/Southbend used 18DP and 14.5 PA, although some of the later Southbends used a 20PA, if I remember rightly from two years ago, All very confusing.!!!Getting the right gears is fraught with problems, Tony at Lathes is a great help. Also last year on E/bay there was a chap in the UK who was selling off gears and lathes cheaply.

Best of luck, and if you know someone with a similar lathe to yours, so that you can measure DP/PA, it could save you some trouble with broken gear teeth. Buying of e/bay is like buying a pig in a poke if the seller does not know the right PA's.

John Holloway

Hi . all this maths and degrees is too much for me. Nobby says use a sticky pin, Its quick. Me all I do is turn up a shallow angle point on a 4mm s/s rod, set the tool to the right hight with metal shims and then cut swarf. when Iv'e finished cutting I superglue the shims to the bottom of the tool holder. If sharpening alters the tool hight, Iv'e still got the turned tapered rod to check. This method is reasonable accurate, But if in doubt, use the centre pip method, Any thing to save time and energy is good.

John Holloway.

hi , cast iron welds need pre heat, plus as mentioned before tap weld area with a small hammer, if you dont have a cool down oven, stick the job into a bag of lime, if you dont have that, use dry cement, Iv'e done welds with a stick welder and use the stitch method of welding, it lessens the stresses, came back next day to get job out of the lime container, and it was still warm, Some welding sticks such as Eutectic are excellent, BUT are expensive, even for a pack of six. but that was some years ago.

John Holloway

PS made a couple of indexable tool holders today, I had to go inside next to air conditioner a few times as the temp even in the insulated workshop was over 32 degrees.

Hi  happy new year to all.

In this months Australian Model Engineer there is an article on this model built by Mark Watkins with some references to sourcing information.

PS its raining and getting warmer up to 29 degrees, Eat your hearts out, for those in the North, I think the pommy cricketers are enjoying it down here.

John Holloway

Hi again.

A good source for magnets to make the bases for dial gauges etc etc, is to take out the magnets from old radio speakers, grind off the spare bits of metal, and the if you are lucky you can drill and thread these new bases, also drop one in a plastic bag, to pick swarf or lost screws and nuts and bolts, invert the bag, remove magnet, find lost items then dump the rubbish, no dirty hands, or splinters.

It's getting warmer and wetter here. John Holloway

Hi, an old method for sharpening files and rasps is to, first do what Ian SC does with a piece of brass or copper tube, then wash them with detergent, rinse off properly. Then put them outside in the cold nights, sometimes also wet them with weak acid ie lemon juice or vinegar you might need to do this a couple of times. But the ensuing rust has left a sharper edge, finaly brush and oil them.

Good luck John Holloway

Peter, Hi.

Iv'e got a Hercus 260 (Australian made) Its the basic model which I bought of E/bay, I got it cheap cause it din't have tail stock, steadies, qc gearbox or toolpost holder, but its a well made lathe. Now I had 2 chucks off  my home made lathe, ie 100mm and 150mm 4 jaw, so I made 2 new backing plates for them, the next problem was, even thought I managed to get the most of the change gears, Although I needed a 25 and 50 tooth gears, the 50 tooth in conjunction with the 63&64 tooth (which are pinned together) allowed me to cut the threads for the for spindle nose which happen to be 8 threads to the inch,???. (they were probably using older stock items for Imperial lathes). So as Bogstandard said its probably due to size constraints or its the only way to cut Imperial threads on a metric lathe.

Thats my input to the discussion, and I know that the back plates fit very well, does this help at all ???. 

Keep at it. John Holloway

Hi, I need enlightening, (no dieting). When I was a young fellow growing up in the West Midlands before the WW2,  I often went with my old man to his cousins large blacksmiths factory, and the first thing all the men had to do, was piddle into the large cooling vat, (no women allowed), The unmistakable aroma is unforgetable, ???? asked why we had to do this, simple lad ! it's give a better edge to the scythes and other tools, they made. Now, down in the silt of my brain cells, I recall reading that the Sarecen and Spanish sword makers did the same thing, Is there something in the urine that does this, or is it a tradition. anyway the only good thing urine does is, if it's watered down it's good for garden ( I dont do this) also just filtered through the kidneys it does wonders for my Lemon tree (I do this when no one is looking). Is there anyone out there who can enlighten us if there is any truth in this, hardening and tempering technique,

Keep doing and not thinking works for me.

John Holloway, (now living in Oz for the last 60 plus years)

Hi Ian, Hercus was a stand alone Australian lathe, milling , shaper, factory etc etc. designed by Fred Hercus, pre war, in South Australia, When Hercus stopped making lathes about 1982 they were selling for $10,000, so were dearer than Myford  or Boxford, they were a precision instrument makers lathe, with geared head stock and power feeds, they have a No4 morse taper and 42mm nose thread, so they are a very solid and accurate lathe, short and long beds, we can still get parts from the factory,  Im'e happy with it, I can rip off 2mm or more in one pass.

PS it's getting warmer 23degrees and raining again. and Iv'e nearly finished the Boll-Aero, 1.8cc  IC engine, I had to stop making it for about 6 months, just need to alter the timeing and make the carby.

Thanks for listening John Holloway

Hi, Ive got a Hercus 260, (looks like a geared head South Bend), the oil filling points are same as a Myford, and as I have some large medical and Vetinary syringes,sans needles, I use these, easy to fill, dont leak, unless inverted. The only problems are, sometimes they seize up if left standing and its sometimes tedious to drip feed, The best part is they are free, and can be used in awkward places ( for oiling machinery ).

PS its starting to get warmer down here, although weve had the coldest Septemeber  for years.

Keep making swarf, John Holloway

Hi Roger.

What if you brought a set of morse taper reamers, they are cheap on E/bay,  and ream the shaft   insitu using a properly aligned holder.  And then check with a good dead centre that you know is accurate. or if you have them, a  set of collets, fitted with an accurate point, or clock a piece of drill steel while this is set up in position. It probably means making some sort of jig to get everthing in line, Best of luck.

John Holloway

Hi, I have had to make a number of dovetail slides, and at that stage had no mill, or a milling attachment for the lathe, making them  all out of different pieces of steel, (cutting the angle with a 9" grinder then fileing and lapping) so after lining everything up, drilled and bolted each ends, I pilot drilled numerous holes, and as mentioned in previous threads, I counter sunk with a modified drill bit,  (10mm in this case)  and let the countersink in, a set distance below the surface, then clear drilled for the threaded section. The benefit of  machining the heads down for a snug fit in the countersink was that, I now did not have put in locating pins/dowels, and everthing stays rock solid. I did not get chatter or squealing when countersinking, and found a good use for old drills. It was a pain in the butt to do but  Im"e Happy with the result.

Bye, it's late and frosty and Im'e too tired to stay up to watch the Footy. have a good day.

John Holloway

Hi, here in OZ you can buy small prepacked rolls of solder, for normal, silver and aluminium, there is only about 300mm  in each roll,The UK probably has the same products in the handyman section of your DIY store.

The last time I welded aluminium, was when I built a forward cab on my 17 foot fishing boat, even though I am a welder, aluminium is not my thing, tying to stop the metal over heating using oxy was a real hassle, cause you have to put in a lot of heat for marine grade Al.

Good luck with the low temp soldering, Lumiweld can some times also be a hassle

John Holloway.

Hi. I think that it was geometers articles published in ME some years ago that gave details on how to true up the chuck jaws (they can be found on this site and the internet), anyway I trued up my worn Bernerd chuck useing his method, which shows how to clamp the jaws.

My chuck has three extra holes at the front which I drilled right through and spotted on to the back plate then drilled and tapped these, then locked a small piece of hardwood in the jaws 20mm diameter which is about the average size.

Put threaded rod through the three holes and then clamped the jaws solid with three pieces of steel plate, you could use engineers clamps instead, that, kept the jaws in the right position, so that I could drill out the wooden block,  then useing a cheap Dremel grinder SLOWLY rotated the chuck by hand, I used the largest grinding wheel I had, BUT the collet holder in these cheap grinders is rubbish it let go.!!!!! I never found the wheel again as it bounced around the workshop, Good workshop practice or what ????.  I only took off the minimal of the most worn jaw but had to take off 5-6 thou off the others, the wear was mostly at the front. Now at 20mm diameter the DTI shows virtualy no run out, as previously mentioned old worn chucks give different readings at other sizes, you can get them refurbished but its cheaper to buy a new one.

Swarf is good swearing at it is not.

John Holloway

Hi, Trying to get the right indexable thread insert is not hard, what is hard, is trying to decypher the correct catalogue index even from Vardex who have dedicted thread cutting inserts, anyway Iv'e seen home made chasers, useing a cut up button die which is then brazed to a suitable holder or clamped on like an indexable insert is, its a thought ??? its also cheaper than buying Die head chasers.

By the way how did you measure the thread down to one thou, I'me flat out measuring 3mm threads over a multible of 10, and still get it wrong.

A question ??? can you get plumbers dies in fine threads to use as a chaser, as  I need to cut threads in alloy for the crankcases in small IC engines, or do some reading on threading.

PS down here in the southern highlands of OZ its the start of winter with temps -2 to 17. which is warmer than London, now I know why my parents and me and my young brother migrated down here in 1949.

Keep up the good work.

John Holloway

Ramon Hi .

Go to the modelenginenews site again. There is a couple of articles on anodising in there some where, aimed mainly at the IC engine builders. 

I have not done any work on the Bol-aero 18, since my last posts, cause Iv'e been lopping/chopping down a few trees, I also have been making jigs for the sieg X2, so that I can hold  accurately the bits that I machined, and then had to take them off the lathe and mill to do another job, Which was idiotic, cause now its hard to replace them in the exact position.

John Holloway.

Hi, just a few thoughts. while I was turning up some cylindical squares.

First try reducing the oil ratio down to 10%-12%, it seems to have an excess of oil or fuel dripping out of the exhaust, that could be put down to a bad air to fuel ratio,

Second idea, is that in the early years small manufacturers had to cut costs some how,

Getting the machineist to make there own needles was expensive, so was buying box's of sewing needles, but there was a big supply of gramaphone needles, unfortunately most makers had different shaped profiles and tapers,So if a hobby model engine maker took one off there own record player, it was a hit an miss affair, The other problem was that 50 years ago, small drills were not the same strength and quality that we have now, and if the home machinist had a worn or badly sharpened drill, if drilled from the needle side of the tube, bell mouthing could occur, As an example put a washer over a morse taper, pull it back, say 20mm and see what the air gap is, then put it in another morse taper, pull it back the same amount, and you will see a much bigger air gap. coupled with a miss matched needle, you now have a hard to tune engine.

So, make a selection of needles of varying tapers, clean up the needle seat, and see how that goes.( MEN has articles on makeing needles and tubes), You need a combination that will allow the coarse needle adjusting screw on your engine to work properly, ie, at least two to three turns of the screw,to get from from low revs to nearly full rev.

I saw an article on making needles, useing the right diameter piano wire, just by fixing one end solid, using pliers or a rod, on the free end and then  heating the the section to be tapered,with a gas burner pulling and stretching the wire to get the right taper, then cutting out the section you needed.

Hope this is some help.

John Holloway

Les, Hi, go to the modelenginenews site, note, there is no spacing between the words. There is a full description of all the ED engines, that is quite detailed, on construction , history, and re-assembly, Iv'e just had a quick look, not the indepth articles even so its comprehensive.

Ramon, Hi, its a bit cooler after the record rains we have had in the SE of OZ. Now that Iv'e cleaned most of the junk and rubbish out I can start making swarf.

Anyway I seem to have read articles by E Westbury and others on the use of various metal combinations, for IC engines, I also think MEN has similar articles, This site, especial if you are a member is absolutley massive, you can read for a week solid and still see everthing that is written and photographed. 

The article on making contra pistons, that fit and work straight of the lathe is an eyeopener, I think that it also refers to cast iron and steel as a contra piston and what the ramifications are.

PS I dont have problems on timeing/logging out (yet !!!!!). thats brobably because I use OPERA as a browser and mail recipient, its also the fastest browser around, I can read, write, make coffey, read links, check spelling and go back to Windows explorer to do other checks. Maybe Im'e just lucky so far.

John Holloway.