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Member postings for John Haine

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

Thread: Arduino Pendulum Clock Design - Comments Welcome
29/09/2020 17:39:12

Dave, progress! Have you measured the diameters of the CF rod in two orthogonal axes? If it is not perfectly circular I think it will tend to swing elliptically anyway.


This is my current clock project transferred to my study to connect up the Arduino. There's a neodymium bar magnet jammed in the end of the rod, sensed by the coil just below. To the right is a Hall sensor for amplitude control. Backboard is MDF salvaged from beneath the bench. It's bolted to my largest angle plate weighed down with three bits of 4x4x1" BMS. Wikipedia beer mat is for levelling

Bob currently too high - target is for period to be very slightly less than one second.

Thread: Power feed for a VM32L mill
29/09/2020 07:05:32

Just to enlarge on that post, GRBL runs on the Arduino and needs streams of g-code commands (and control) on a serial port. Apart from configuration data (e.g. steps/mm) it doesn't have persistent data - this sits on the controller. GRBL Controller has a number useful features, including the ability to stream g-code programmes to GRBL, but at the moment the only thing I use is jogging which does most of the things you want. In particular it has 4 predefined "soft keys" that can have g-code macros assigned to them.

More details:



Let me know by PM if this is interesting for your application.

Edited By John Haine on 29/09/2020 07:06:02

28/09/2020 22:03:37

I use an Arduino Uno with cnc shield, a Bluetooth connection to my Android phone, running GRBL o the Uno and GRBL controller on the phone. It does what you are asking for.

Edited By John Haine on 28/09/2020 22:04:12

Thread: Copper Plaque Identification
27/09/2020 12:27:05

Try Grace's Guide


Thread: In praise of M-Machine
26/09/2020 13:30:23

Well I ordered some magnets from first4magnets and a bandsaw rip fence for my Femi from Axminster yesterday late morning, both predicting delivery from Monday, both turned up with the postie this morning.

Thread: Restoring a wooden tool box, help needed
25/09/2020 09:48:44

One of these (in worse condition) restored on "Repair Shop" last week. Involved removing the top, splicing in a new bit of oak, and forming joint fingers. Joint was not glued!

Thread: Vacuum Pump Advice Please!
24/09/2020 21:53:24

Depends on the requirement. The Shortt ran at very low pressure to maximise Q, but even at lower vacuum the Q increase will be worthwhile and it should eliminate barometric rate variations.

24/09/2020 20:41:04

According to Wikipedia the Shortt free pendulum tank was evacuated to 30mm mercury - ~39 mBar.  In 1984 Pierre Boucheron did some measurements of the stability of a Shortt pendulum electronically impulsed using one preserved at NIST in Colorado.  Apparently the tank vacuum was intact after something like 30 years.

Edited By John Haine on 24/09/2020 20:49:30

Edited By John Haine on 24/09/2020 20:51:58

Thread: fly cutter wear
24/09/2020 18:51:40

not enough clearance?

Thread: What sort of light source to use a strobe disc?
24/09/2020 18:50:19

You do get some variation in intensity at 100 hz with a filament lamp, which may be enough, but a neon is better. Or these days an led but without smoothing. If you had 3 filament lamps one on each phase that would have much lower total intensity variation, but not a single bulb between 2 phases.

24/09/2020 17:46:05
Posted by Ian Parkin on 24/09/2020 17:35:06:

What sort of illuminators were used in record turntables?

Mains Neons.

Thread: Mounting a collet chuck.
24/09/2020 15:00:08

Another approach is to shrink fit (or Loctite) a spigot into the hole in the backplate and turn your own chuck body. Collet nuts are easily available, including ball bearing. The threading and taper are fairly easy to get right.

Thread: Climb Milling any implications
24/09/2020 13:27:15

Emgee, so am I!

24/09/2020 12:31:44

As to where to start, often it depends on where the chips will go! I prefer to mill in a direction where they fly off to the left/back rather than all over me!

Thread: PP Thornton (successors)
23/09/2020 18:40:38
Posted by Baz on 23/09/2020 18:02:00:

John Haine if you substitute gauge plate for soft HSS and use the Ureaka form relieving attatcment it is perfectly do-able in the average workshop.

Indeed, but in another thread people have been discussing manufacture of HSS tools on the Quorn.

23/09/2020 17:53:09

Well, that was an interesting read Michael! Not entirely clear, but it seems that they produce the cutters using in effect the "button" method to impart the required profile to the teeth, the "buttons" (or their equivalent) being made from carbide, ground to shape using diamond wheels. The "soft" 12-tooth HSS blank is turned on a form-relieving lathe after gashing, then vacuum heat treated to harden. Doesn't sound easy to reproduce at home!

Thread: Climb Milling any implications
23/09/2020 15:51:26

I will climb mill on my little CNC (Novamill) with no problem as it has ballscrews and is very rigid.

On the bigger VMB I only climb mill when finishing ali with the side of a cutter - take the last main cut normally then wind back without moving the cutter or maybe just adding 0.1 mm more. This gives a much better finish and so far hasn't resulted in grief.

On steel on Chris' little mill especially making pinions I wouldn't even try.

Thread: PP Thornton (successors)
23/09/2020 15:46:24

Aha! Good stuff, I'll peruse that.

Thread: Climb Milling any implications
23/09/2020 13:43:31

With climb milling the cutting force pulls the work through the backlash and suddenly increases the depth of cut. On your mill I would suggest you don't even try, especially cutting pinions.

Thread: PP Thornton (successors)
23/09/2020 10:29:27

Good link, thanks Michael! Now if we had a video of how they shape the profiles on their HSS blanks...

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