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Member postings for Dave S

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

Thread: CNC Knurling
09/09/2021 12:59:16

This is microPython, rather than Python, but the file handling is the same IIRC.

file writing on a pico

The code snippet (culled from that link):

#This writes whatever is passed to it to the file     
def WriteFile(passed):
    log = open(LogFileName,"a" #open in append - creates if not existing, will append if it exists

should help 



Edited By Dave S on 09/09/2021 13:01:19

Thread: It would be nice to know........
09/09/2021 12:53:31

Last time I used mine in reverse was when I accidentally made a left handed cutting tool to create the spaces on an escape wheel.

Didn't realise I had it reversed until I got the whole thing setup in the mil and ready to run - then a bit of a 'hang on... something is not right here' moment.

Glad to have reverse for that - the cutter took a while to make.


Thread: Green Anodising Dye
08/09/2021 16:55:55

Pretty sure pimoroni only manufacture electronics and laser cut plastic stuff.

There was no machining or anodising line there last time I visited.

Does the anodising dye have recommended current densities and times? Sound like the die is washing out of the anodised pores before they become hydrated.

Edited to add:

Is the dye water based? You could try boiling the part in dye rather than plain water if that’s the case.


Edited By Dave S on 08/09/2021 16:57:22

Thread: I need to cut chamfers into x64 pieces of mild steel - any advice?
06/09/2021 21:55:17

Busch burrs are made from HSS as far as I know.

Tungsten vanadium steel IS a high speed steel. The alloying with tungsten and vanadium promotes strong carbide forming tendencies, which remain hard at elevated temperatures.


06/09/2021 17:55:07


06/09/2021 17:53:49

Yes. The bridge over the belt does not need to be 1 piece, the slot can be formed by leaving a gap between 2 pieces.

atrach the plate over the belt of the belt sander - details left to the reader as it will depend on the actual sander. Make sure the gap belt to plate is small as possible.
the wedge hold the to be chamfered plate and you guide the plate through the slot until it stops cutting. DoC is limited by the jig - you can’t push the large flat bottom through the slot - a bit like how the cut on a wood plane is limited by its sole


Thread: Bench grinder - wheel grit
06/09/2021 17:24:53

46 grit and 60 grit would be a reasonable pair. If you want a polished finish grab a resin bonded diamond wheel.

Yes they are theoretically no good for HSS, but in practice mine is still sharpening HSS, Carbide and the odd bit of silver steel just fine after years of use (and the tools are also fine)

Why are you dipping HSS?

Hold the blank in a pair of mole grips and grind it.
You will not draw the temper - that’s why it’s called High Speed Steel. It has enough red hardness to cut metal…


Thread: I need to cut chamfers into x64 pieces of mild steel - any advice?
06/09/2021 17:16:32
Posted by Dave S on 03/09/2021 17:15:39:

Literally a 5 second design sketch:

If you look I’ve done the design, it just needs dimensioning…

The pins on the angle, in conjunction with the table over the belt set the max DoC.

make it from MDF -more than robust enough for your current run, and simple to work with hand tools.

The accuracy will be limited by the amount of care you take, but your making 1, and then the 64 will end up as matching.

Again I think are overthinking the problem


Thread: Need some help/advice
03/09/2021 19:56:19

I’ve never had a problem with the 6” (ish -160mm) vice on my TOS.

Table is 10” wide



Thread: I need to cut chamfers into x64 pieces of mild steel - any advice?
03/09/2021 17:16:33

CAD vs Pencil My computer is off (typing on phone)

03/09/2021 17:15:39

Literally a 5 second design sketch:

03/09/2021 17:00:04

Jig is a simple work holding device that allows a quick, repeatable setup.

in this case it probably looks a lot like a block with a 45 degree face and a strap clamp.
Add a plate over the belt with a slot in it - think wood plane sole sort of thing.

poke jigged plate through slot into belt. Large block of jig lands on the plate repeatably.

all you have to do is make sure the jig sets up so the plates to be ground are in the same place each time - assuming the holes are at a known location 2 dowels in the face of the jig will do that.

I do not have that unit, and I would do this sort of thing in my chuffing enormous mill, with a different but similar function jig.


03/09/2021 16:33:14

One of these: **LINK**

add a simple jig to hold the part at the correct angle, with a stop to prevent grinding too much off

edited to add: use the belt in horizontal mode, not the disk. 


Edited By Dave S on 03/09/2021 16:35:16

Thread: Could you write for MEW?
31/08/2021 14:46:59


Think there may be a typo in your email address?


Thread: Is there such a thing as an 'external reamer'?
26/08/2021 12:28:12

Just remembered seeing this:

A rolling blog of everyday life on and around the workbench (

where Stephen uses an ER collet as a cutter.


23/08/2021 15:24:38

In brass its a fair bet that for 12 an unhardened steel tool will last.



was made to produce a stem tube and crown guards in brass:



Its much smaller, but its not really any different in process. Given the tool is still silver coloured I almost certainly didn't heat treat it.

Make the hole the correct depth and it wont overfeed.

I would bore a suitable hole in a piece of steel bar, ensuring it was the correct depth, then just use a hacksaw /files to gash the teeth. Being brass no rake is required. As its a spigot on a flat plane, rather than the tube feature I was making there shouldn't be a tendency for the chips to pack up - they can just fall off.

To use turn the spigot to correct length and a small amount oversize in diameter, then run tool in in the tailstock.


Thread: Harrison Remontoire info
19/08/2021 12:39:12

Not as a member, which I assume is what you mean.


19/08/2021 11:46:14

Thanks, I hadn't thought to look at his marine clocks.


Thread: Ruggedising a Type 17 Stepper motor electrical connection
19/08/2021 09:57:13

The 'quick and dirty' way I have often employed is to turn the motor so the wires are at the bottom, secure to the motor body with a cable tie and 'pot' the whole connector and tie in hot melt glue.


Thread: Harrison Remontoire info
19/08/2021 09:23:43

Morning all,

I was recently given a copy of Decoding Harrison - which is a series of essays about the Burgess Clock B - based on Harrisons designs.

There is mention of having a remontoire but details of the actual design are lacking.

Anyone have a good primer on remontoires in general and the Harrison one in particular?


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