Member postings for Andrew Johnston

The answer is yes, that's exactly what I did when I needed to cut circlip grooves on 10mm rod.

Andrew

They don't need to be fancy; should take a few minutes to cut/file from sheet and drill/tap the hole. No need for any machining.

Andrew

Dig a hole in front of each machine tool?

Andrew

The screw is there to stop the insert falling out. It shouldn't be taking any significant cutting forces. The cutting force vector should be pushing the insert into the pocket, so the holder takes the forces, not the screw.

Andrew

For me conversion of a 3-phase machine to single phase means I'd pass. I suspect that the availability of cheap VFDs means that any single phase premium is a lot smaller than it was. Even for hobby applcations my time is valuable and is taken into account when deciding what to do, and how to do it.

Andrew

Lovely bit of kit; did it come with all the gears, brackets and a tailstock?

It can be used for direct indexing using the plate behind the chuck, simple indexing using the division plates and compound, and differential, indexing for divisions not available using the standard division plates. As stated above, in conjunction with a universal horizontal mill it can be used for milling helical gears:

Or on a Bridgeport for high helix gears:

Like this:

Andrew

Gauge plate is not available in thin sheets. In general shim stock is not heat treatable. I have made "spring" clips from shim, but it needed annealing first. Otherwise it fractured when bent.

It would be sensible to decide what properties are needed and then pick a material to suit, rather than pick materials at random and ask if they will be ok.

Andrew

It will form well, but is a mild steel and contains very little carbon. So it can't be hardened and tempered.

Andrew

Edited By Andrew Johnston on 28/03/2023 00:36:44

Wiseman Threading Tools do a wide range of spares.

Wiseman

Andrew

I suspect the force on a chip due to gravity is going to be tiny, and for long chipping materials of no consequence.

Andrew

The shape of the swarf from my insert parting tool:

Parting off under power feed gives a very good finish on the part, and on the remaining stock. So no cleaning up is required. One has to look at the whole picture before saying something isn't necessary.

Andrew

Nearly always power feed on the centre lathe, minimum feedrate is 4 thou/rev, and usually 6 to 8 thou/rev. On the repetition lathe parting off is manual. But controlled by a lever not a screw thread and dial. Just pull hard on the lever to ensure a decent cut.

Andrew

Like this:

Lathe works equally well in both directions. To change direction just flick an electrical switch, no need to stop the spindle first.

Andrew

I don't bother, just sweep the floor afterwards as part of the post machining clean up.

Andrew

Ah well, looks like I'm a fool. Never felt the need to use a rear toolpost for parting off (*). But a rear toolpost is convenient when using a hydraulic copy unit:

A thought: in the same way that 'practicalmachinist' bans discussions of hobby machine tools should this forum should ban discussion of industrial machine tools?

Andrew

(*): Not quite true; on my repetition lathe I part off from the rear, but then again all tools are on the rear.

I buy sizes as needed from professional tool suppliers. Most of my metric threading gear is Dormer, but I also buy from Drill Service, commonly FEW brand. I often buy spiral flute taps rather than a set of hand taps. I no longer buy from Tracy Tools.

Andrew

French Engineering Works

Normally sheet form.

Cold drawn steel

Andrew

I thought bright bar was formed by cold drawing through a tungsten carbide die? The drawing process stresses the outer layers; hence the distortion when the outer layer is removed asymmetrically.

Andrew

Hydraulic copy unit:

Turn the larger ball and a parallel section first, and drill/tap the M12 hole, and part off. Locate larger ball in an aluminium cup chuck held with an M12 bolt. Turn the smaller hemisphere. For drilling/tapping the smaller holes use a universal dividing head with item mounted on a cylinder with an M12 bolt.

Andrew

I use a dial test indicator on the back of the fixed jaw aiming for 0.01mm across the jaw width. Although all three of my mills have nominal 5/8" slots in practice they are all slightly different widths so I don't use tenons. Another issue with tenons is that they can get damaged, or damage the table.

Andrew