Member postings for Brian G

One big advantage of a 100mm chuck is that you can use the full size of the spindle bore (our 80mm independent 4-jaw allows this but not the 3-jaw). Generally the lathes with 100mm chucks also come with a quick release tailstock, and are probably worth getting for that feature alone - getting a 17mm spanner under the compound handles is no fun.

Brian

I can see the point as ratchet spanners are often smaller than flex ratchet handles but why make an adaptor? Halfords do a set of three for 11 quid **LINK** and a heavy-handed mechanic tells me they honour their lifetime guarantee.

Brian

My son carried his Warco mini-lathe upstairs on his own, but calling it "portable" is probably going a bit far, especially as the new "super" model is 2" longer and has a larger chuck. It is a bit cramped, and I would advise if you get one you try to arrange enough space to slide the tailstock off when it isn't needed - your knuckles will thank you. On the headstock end, don't forget that the gear cover needs about 4" clearance to unscrew and slide off as well.

Brian

Just found this - not much (or indeed any) use for BS/BSF/BSW, but perhaps explains why there are so many spanners in a metric set. Evidently metrication != standardisation. **LINK**

Brian

I assume Microchip to chose this exercise because there aren't many ways to demonstrate a lookup table using a push button, a potentiometer and 4 LEDs, the only inputs and outputs available on their demo board.

Turning the pot varies the voltage from 0V to Vref and the analog to digital converter returns V/Vref x 1023 in binary, which is the subject of an earlier lesson in which the high 4 bits are displayed on the LEDs. The lesson on lookup tables uses the conversion to Gray code simply as a way of demonstrating the table's function with these limited resources, the LEDs lighting in Gray code sequence as the pot is turned.

Brian

Gray isn't dead yet - one of the programming exercises that came with my PicKit 2 was to create a lookup table to convert the (binary) result from a PIC's A-D converter to Gray code.

Brian

I hadn't thought of synchros, possibly because as a child I never really understood my (dockyard electrical fitter) dad's description of them, and partly because it was for driving a train, not training a gun

In the end, the most easily understood/repairable option is probably to use an ALPS motorised + friction clutch pot for the master control and push buttons for the others. Then again, they are dual-gang, and it would be fun to read the resistance of the current master one with a PIC, convert it to a digital code and drive another to the same position... I would just have to burn a few spares for after I am gone.

Brian

And you couldn't just buy a standard key in that size, it has to be the special automotive one with a sleeve handle to sit in the toolbox alongside the extra long T handle key to adjust the K Jetronic mixture.

Brian

This table is very useful at a pinch, giving BA, metric, AF, BS and WW sizes from 10BA up to 60mm **LINK**

I think the worst thread size in this respect is probably M12. Depending on standard, it requires 17, 18, 19, 21 and 22 mm spanners. I am curious about one thing though, why does my Britool set have 9 and 15 mm spanners when, as far as I can find, they shouldn't fit anything?

Brian

I'm trying to avoid anything that couldn't be replicated without me Neil, and sadly even burning a PIC falls into that category (only one member is familiar with Arduinos and he is probably leaving soon). Might have to give it a try though, I could always leave a programmed "module in a box" as a spare.

Brian

Thanks

It seemed too good to be true as unless there was some kind of feedback in the driver, the only connection between the first rotor and the second would be from induced current - but I had to ask

The application was to allow a single "cab" to be controlled from multiple locations by turning knobs, a slip clutch could protect the potentiometer, so all the knobs could rotate continuously and catch up any lost steps. I really don't want to go down the rotary encoder and software route as I would be the only member who understood it, which is never a good idea. It looks like a conventionally motorised pot with +/- buttons at the remote location will be the simplest solution, and the easiest to repair.

Brian

Back in April, Neil, describing his Prusa 13 Build **LINK** said "Something that surprised me, was the effect of having two steppers wired in parallel for the z-axis. You turn one, and the other moves in unison!". Does anybody know if this is normal behaviour for stepper motors or if a particular combination of motor and driver is required?

(If practical and reliable, it would provide a way for a model railway controller to be operated from more than one panel, solving a problem at our club.)

Brian

Hi David

Martin Evans gives 1/16 or 3/64 copper or brass snap head rivets for LBSC's unfinished Evening Star in the same gauge, but doesn't mention spacing I'm afraid.

Brian

One thing to watch out for Matt is that the Prest-O-Lite (POL) connectors used on Propane cylinders in the UK may not be suitable in Canada (according to Wikipedia the POL connection is illegal in the US **LINK** - I assume as you are thinking of buying from the US that the same is true in Canada). As a result you may be better to import the torch, nozzles and hose but buy a regulator (or a hose failure valve) locally to suit the available cylinders.

Brian

We used to have "Out of Town" to showcase traditional crafts, but there doesn't seem to be anything like that now. Perhaps the difference is down to early exposure in Germany to "Die Sendung mit der Maus" (The Show with the Mouse) and its excellent short documentary films like this which shows the manufacture of lolly sticks.

Brian

ER collets can also hold drill bits, so there is no need to change to the Jacobs chuck for drilling.

Brian

Just got the chance to measure our 80mm mini-lathe chucks. The 3-jaw has a 16mm bore, whilst the 4-jaw has a 22 mm bore, allowing full use of the 20mm headstock bore. (Amadeal list a replacement 100mm spindle, but the bore is still 20mm).

Brian

Is there a specific reason you want the new version of the mini-lathe Martin? As Dave says, it could be a while before any appear second-hand - although it is worth checking if Warco have any ex-demo at their open days (there is one in November), my son's mini lathe came that way with enough of a saving to pay for its tooling.

Apart from the brushless motor, the rest of the improvements can be easily retro-fitted to a second-hand lathe if you find you actually need them. (I fitted a speed readout like this **LINK** for less than a tenner including a case).

One problem with the old model's 80mm chuck is that it has a smaller bore than the headstock, so an 80mm or 100mm 4-jaw with a larger bore is a useful addition - at least with the mini-lathe, accessories like chucks, steadies, quick-change toolposts and milling slides are readily available, as well as the full range of spares.

Brian

What is the point of having more words than any other language when we have so many meanings for each word? How would we explain to a foreigner the difference between "dogging" and "ferreting" * and why neither involve animals?

Back on topic, I remember a "rabbit" a something made "off the books" for use or sale over the wall. I wonder what names these were given elsewhere?

Brian

* As in "dogging his footsteps" and "ferreting around in the cupboard" of course, I wouldn't want to lower the tone...

 Hi Dean

In most respects (apart from the earliest models) the cast iron DB is nearly identical to the later and much more common aluminium or Zamac SL models. With the exception in some cases of the milling post and the headstock riser block, the tooling is identical. When it comes to cutting tools, 6mm may work without shimming, 1/4" HSS and 6mm carbide are fractionally too tall.

Unimat 3 toolposts and top slides are too high for the DB/SL, and the QCTPs sold for 7x12 mini lathes are too big (I tried my son's). Some of the members of the Unimat Yahoo group **LINK** (it is worth joining for the files section alone) have these US made QCTPs and appear very happy with them: **LINK**

Another option is to make additional toolposts (possibly from aluminium like the QCTPs) as they can then be exchanged without shimming by loosening a single cap head screw.

Brian

Edit:  I just saw on another thread that you are in the US.  In that case take a look at Toms Tool Store for Unimat spares http://www.tomstoolstore.com/

Edited By Brian G on 26/09/2017 10:07:17