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LOL@ Norman. No stakes involved. There is no doubt about the level of "*******ry" involved in the manufacturing industry. But if you are making your own screwcutting tool, might as well make it 55 degrees to match the spindle. Taps are handy for cleaning up the final thread but I don't fancy the...

A second way to double check my calculations above is to use the chart linked to above by fcheslop. It lists a 12tpi thread for nominal 1/2" BSW. So its major diameter is .500". To make it relevant to 1-1/8" diameter, add 5/8" or .625" to the diameters quoted. So the thread depth the chart...

Well, nominally the minor diameter would be 1.125" minus your thread depth of .053" x 2. (As derived from the formula Depth = .6403 x pitch) So 1.125" - .106" = 1.019" minor diameter. To allow a bit of tip clearance, I would bore the hole to 1.025" diameter. Then proceed screwcutting from...

PS, system won't let me edit previous post. If you are cutting a female thread, make the inside diameter of the hole five to ten thou larger than the calculated minor diamter from the formula I gave. This gives tip clearance and ensures threads engage on the flanks, not the tips.

Basic screwcutting. For Whitworth, thread depth = .6403 x pitch. So that comes to .053" thread depth. Don't get too carried away with trying to cut the perfect thread to exact BS standard threadforms etc. That is the realm, as Martin Cleeve calls it, of "overzealous amateurs". Standard...

How does that work? Are you making up three hardened, threaded wheels that somehow fit into a G-clamp type pipe cutter? Sounds interesting. Stainless is tough stuff to work. Might be worth buying some 2mm 306 wire rather than the welding rods you are currently using. If all else fails...

You could make your own. It will be a standard taper of some sort. Probably Morse. But you could set your lathe up to make your own easily enough. Set a small dial test indicator gauge on the toolpost and set it to run on the rear side of the taper in the spindle. Adjust top slide until the...

Haha, yes must be cut-price seasons made down to a price in the Far East.

Well, it's not raining here. And the temperature is about 75 degrees F. But it is the middle of winter.

Nice one. The Kiwi was a design by the legendary E.T. Westbury back before World War 2. There is a potted history of it here http://modelenginenews.org/etw/kiwi/kiwi_history.html And this https://www.model-engineer.co.uk/sites/7/documents/etw-kiwi-mk2-pt1.pdf set of drawings and construction...

Not sure if I am misunderstanding what is being said, but it can depend too on the weight of the workpiece being moved back and forth on the blued surface plate, or how hard it is pushed down against the blued up surface plate. Under light pressure, blue will transfer from the surface plate to...

So can plain bearings used back to the turn of the century. My old Drummond with parallel bronze bushings and my ML7 with parallel white metal bearings will both turn out work within half a thou or less. It's all in how you set them up and how you use them.

Difficult to say. Hercus South Bend clones sell for $1500 pretty regularly, sometimes less, sometimes more. Ditto ML7s. At the other end of the scale, and globe, there is an S7 on the Model Engineer forum for 300 quid. Says it has some rust and may need a bed grind but who knows. Looks passable...

You are doing well. Must be a very nice example of the breed. I think they are now priced at about 8000 Pounds new so with shipping and import/GST taxes etc would be well over the $20,000 mark landed in Oz. Half of brand new price could be seen as pretty fair for someone who really wants one if...

Comstock: Compared to the USA, yes good quality small lathes are fewer and further between. But Myfords seem to have developed a mythology all of their own. Local clones of the South Bend 9" - the Hercus - sell for more like $1500 and are in my opinion a better machine. But that's just me.

$12,000 may be a bit optimistic. There's three Super 7s on Gumtree right now ranging from A$2700 to A$5900.

Nothing so deluxe as roller bearings for Myford. The Super 7 has a large tapered bronze bushing for the main headstock bearing that runs against a tapered section on the spindle. The other end (change gear end) runs on two ball or roller bearings IIRC. The procedure for setting up the spindle...

I don't think there is one table outlining the differences that I have ever seen. Basically they are based on the same machine. But the Super 7 had improved headstock bearings, longer cross slide and in some cases power cross feed. But Myford made various different models over the years...

A lot of those Chinese claimed horsepowers are more like ponies. There is no way those small, single-cylinder direct drive "2.5HP" air compressors at SuperCheap and Bunnings are that powerful.

Stirlings seem to scale OK. Especially a relatively small change like you mention. It's best to try to keep the ratio between the swept volume of the power cylinder to the swept volume of they dispacer cylinder about the same. So if you increase the bore of the displacer cylinder by a few per...