Member postings for Dave S

Should be a 7 or 8 page brochure. The company was Phase Vision, so you could always search phasevision.com on the wayback machine.

Sadly ran out of money, as with a lot of startup / spinouts.

Dave

I seem to recall differing gear tooth counts can be accomodated by pitch shifting the gear.

Dave

John,

This should link the the sales pdf: Wayback Machine (archive.org)

Basically project a load of straight lines, take a photo form the side, do some maths to decode the bendyness the camera sees.

A quick google shows there are several parallel port HATs available for a Pi - thats probably the route I would take if I needed to.

Dave

Its the best Pi yet.

Would recommend getting the cooler or the dedicated case with fan in it - the CPU runs quite a bit hotter than the 4 - not dangerously so, but hot enough that I'll be adding a cooler once I get round to it.

It can also peak a lot of current from the PSU, so whilst the 3A supply for a Pi4 is fine (that's what I'm currently using) if you don't have a lot of things hanging off the USB etc the new supply is designed to support maximum performance. I will be buying (with my own money) one of those when they become available.

Seeing it run with a pair of cameras and 2 4k screens was impressive - I can see it being the basis for a Projector + cameras shape measurement system at 'fairly' low cost. (I used to do precision high speed large volume optical metrology at a previous job).

The PCIe connector is going to open up some interesting possibilities...

Interestingly the feature the Pi team seemed most pleased with was the power button...

Dave

I'm Head of Engineering at a Raspberry Pi Design Partner.

One of the harder parts of the job is knowing the stuff which is coming and not telling anyone...

Dave

Its more like a 5 year old laptop really...

Totally usable as a 'normal' computer.

Also not many old laptops can do 2 screens at 4k/60, have 2 cameras and GPIO.

I think this one is going to end up as the CNC controller for my CNC build.

Dave

Never fix a working machine…

Dave

Working for me right now.

**LINK**

Dave

Thanks all.
i am aware I’ll need a couple of micrometers to cover the range.
considering getting a full set, as I don’t have any metric mics at the moment

Dave

Evening all,

Contemplating some new micrometers, I need to measure 100 - 150mm range things more accurately/repeatably than with very-near callipers.

I don’t really have the budget for mitutoyo, and given M&W seem to be generic Chinese now I looked at the other options.

Noticed Dasqua brand - never heard of them, but seem to be cheap enough and claiming DIN compliance.

Anyone got actual experience with them?

Dave

Looks like a filing rest.

Dave

For an alloy head and steel insert a shrink fit would be ok imo.
heat head, freeze insert get stuck halfway in and learn some new curses

Dave

I would consider a spacer for the outer races, then the nose nut can be locked up tight.

To create the right preload is a case of making the inner race and outer race spacers different lengths.

if you have access to a surface grinder then you can make them initially at the same time - this creating a

paired length, and then selectively lap the inner one shorter.

On the back nut a pair of lock nuts should do.

Dave

I use the quill, but it is INT40 and has a power down feed.

Dave

The cheap camping stoves take a cartridge that is somewhat like a lighter refill - this sort:

**LINK**

maybe you could use this refills and butcher the rest of the stove to suit?

Dave

Pretty sure Isopon is a polyester rather than an epoxy.

They cure in different ways. The hardener for polyesters is a catalyst that speeds up the reaction - but they do set on their own.

IIRC epoxy is an addition reaction, where both parts are required for the chemical reaction to occur.

Dave

Last time I made a watch hand with a pipe I turned a disk with the pipe in it, then cut away the excess using a jewellers saw.

Bit of filing later and I had a small seconds hand for a pocket watch.

Will see if I can find the pictures.

Dave

It’s nice to see one of my PCBs in the wild.

Dave

The guys at Emco were concerned with engineering solutions.

Elegance in engineering is mostly the art of compromise.
Would a cast iron saddle on a lathe of that size work?

Certainly, my watchmakers lathes and Super Adept both have cast iron parts there.
Would it work better than one made from mazak?
Probably not, and certainly not if you also factor the cost in.

The Unimat is a nice little lathe, but it’s also a cheap little lathe. Cost is a major factor in making something sufficiently not shit which is also useful/ will make a profit.
If cost is no concern then different compromises apply.

Im (possibly unfortunately) of the general opinion that working well enough beats perfect every time.

The leadscrew bearings I wasn’t especially concerned with rotation constraints but rather length ones.

I’d need to check, but I’m pretty sure the leadscrew on my CVA (a not insignificantly engineered Toolroom lathe) is only axially constrained on one end. I don’t think that was a cost decision given the machines end use…

On my Unimat the simple addition of some molyslip grease to the end of the leadscrew once in a while, combined with careful adjustment of the hand wheel/acorn locknut gives totally acceptable results. The forces on the leadscrew are not large, and a roller thrust bearing is overkill.
That the LH end (headstock end) is “floating” makes square root of a gnats fart difference, all the thrust and guiding accuracy is between the bed end (tailstock end) and the saddle nut.
Over constraining the leadscrew by adding tight fitting bearing blocks to both ends is imo a bad engineering decision.