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Member postings for Martin Connelly

Here is a list of all the postings Martin Connelly has made in our forums. Click on a thread name to jump to the thread.

Thread: Boring tools fitting question
07/03/2020 12:32:54

Correct as shown. Gives clearance below the cutting point.

Martin C

Thread: NEMA selection for electronic leadscrew
06/03/2020 21:29:39

Temperature of stepper motors is not a good guide to a good system. As hybrid steppers monitor position the matched drivers back off the current when they are stationary so in practice do not get hot doing nothing.

Like Blowlamp my experience with hybrid closed loop stepper systems is no resonance on lathe or mill.

Martin C

Thread: warco lathes.
06/03/2020 21:08:21

Smart & Brown Model M mark 2 is left hand carriage handwheel.

Martin C

Thread: Help identifying workshop contents
06/03/2020 09:52:14

Start off by googling images of some things. Try the following for starters.

Micrometer

Digital caliper

Vernier caliper

Gauge blocks

Slip gauges

Surface plate

Height gauge

1 2 3 block

Martin C

Thread: NEMA selection for electronic leadscrew
04/03/2020 12:29:02

If you buy closed loop stepper motors you can have an error signal to stop things if there is an issue with lost steps. It may cost more initially but you are only doing this once so may be a consideration. If you then have a slightly smaller stepper motor the occasional times you try to move things either too fast or too hard the error signal will trigger. Leadshine make closed loop driver and steppers but there are probably others, I haven't looked for a while.

img_20181021_125704.jpg

This photo is of a rotating ball nut operating a push/pull ballscrew connected to the carriage. Note the small stepper motor. It is a Leadshine 3 phase closed loop matched to their driver unit.

Martin C

Thread: ER25 closing nuts
02/03/2020 18:30:58

Putting a short stub of 15mm into a collet may be a problem, it is possible to have the part at a slight angle. You should not assume the part will be pushed into the perfect position by closing the collet down on it. This is the type of part where soft jaws help. You can machine the jaws to hold the diameter correctly and also a rear step to tap the part down on to.

Martin C

Thread: lathe spindle runout
02/03/2020 12:51:16

Quote attributed to Voltaire. Quote

Martin C

Thread: Ebay Chancers
01/03/2020 16:49:27

£22 for p&p, I could pick it up and have petrol money left over from £22. I think my car would do 120 miles and back for that much money.

Martin C

Thread: I'm making D reamers on a ML8 please help me get a proper lathe!
25/02/2020 19:28:58

Sam, Google is your friend if you know the name of what you are looking for.

morse lathe socket

Martin C

Thread: Deep hole "D" bit advice needed.
24/02/2020 17:48:37

Try drilling 12mm from both ends and then a d bit. See if it works.

Martin C

Thread: I'm making D reamers on a ML8 please help me get a proper lathe!
24/02/2020 17:41:59

Powered feed on a lathe is normally driven by the rotation of the spindle and therefore a chuck fitted to the spindle will rotate as well. There are a few ways to overcome this for your needs, mount the workpiece between centres and use a clamp to stop it from moving (omit the lathe dog that would usually be used to turn the workpiece) is the simplest. Alternatives are to adapt the lathe with something like the electronic leadscrew (ELS) or to go full CNC. I think the second two are probably something you don't want to do.

Martin C

Thread: Chuck back plate material
24/02/2020 17:31:44

I suspect that the reason cast iron blanks are readily available but steel blanks are not is that a cast iron backplate is the cheapest way to supply material for machining to size. I have made a steel backplate from a piece of plate but didn't machine the back apart from the register area. Just seemed unnecessary for the chuck it was for. A cast blank requires a lot less machining to reduce the weight.

Martin C

Thread: PROXXON LATHE
23/02/2020 11:56:09

You could buy a small planetary gearbox with a ratio to suit your needs. Make a suitable jig to hold it on the lathe bed and work towards the tailstock end. Just need some way to hold the workpiece in the gearbox output.

Martin C

Thread: Upgrading to Stephenson Gear
22/02/2020 22:59:51

Have a look at Elmer's VR75 VR75 plans

Martin C

Thread: Mini Lathe
22/02/2020 22:40:18

Read at this thread. How to post pictures

Martin C

Thread: Cylinder bore measuring
22/02/2020 18:48:48

The Fowler gauge is marked to 0.00025" (quarter thou) and you could theoretically estimate between the marks. Not having a temperature controlled workshop or inspection room I doubt I will worry about microns.

Martin C

22/02/2020 16:27:26

This is my Fowler Bowers 3 point 0.75" to 1" bore gauge. I also do not have a ring gauge to check it against.

Bore gauge

Martin C

Thread: Warco Minor Mill - Spindle Lock
21/02/2020 23:16:15

I have a single ended spanner for the flats on my ER32 collet body. It is long enough that when it is on the chuck I can turn the spindle to the point where it is against the column. It is a good enough fit to the chuck to not fall off easily. Pressure on the nut with the nut wrench pins it there freeing a hand to hold the bit going into or coming out of the collet. Initial loosening or final tightening is done with the two tools in hand in the normal way, the nuts are ball bearing versions.

Martin C

21/02/2020 18:32:30

I have a Bridgeport drawbar on my similar mill. The thick end stays above the belt cover and has spanner flats. I use this to tighten the R8 collet holding the ER collet chuck by means of a ring spanner on the drawbar and one on the ER chuck. Once there is some grip by the R8 collet you can put on plenty of torque. It is also good for removing the ER chuck. My ER chuck has flats and general tool change is by use of a spanner on these flats and an ER nut wrench.

I don't need to worry about the drawbar protruding above the cover as i don't open it often as I have a VFD.

Martin C

Thread: Simple drawing package
19/02/2020 19:31:27

This site has a list of 14 free CAD packages. May be worth a look. Free CAD software

Martin C

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