Member postings for Colin LLoyd

Sorry - last post completely round the wrong way - I was thinking of the male and female tools - not the resultant machined threads. So best to "Tap" the female thread first, then us the split die to make a tight fit male thread.

Thanks Hopper - that makes sense. But a useful bit of info, implied in your answer, is that if you are making matching threads, then you should make the male thread first because then, in making the female thread you have this adjustment - that would be absent if you made the female thread first. That is a very useful thing to know.

In this months MEW (Autumn Special 2018 - No. 272), Neil in his "Lathework for Beginners" series describes that Split Dies can be adjusted to get an accurate thread size - without saying how you would measure the difference in diameter - and why you might need to do this?

I have a range of split and unsplit dies, courtesy of my late father, and I have never questioned why the two types were different - assuming that this was a manufacturing option. I can see that by adjusting pressure on the screws in the die holder you could alter the overall diameter of the "screw" but never thought to do anything other than make certain the die was secure in the holder, whilst aware that undue pressure would alter things.

Can someone please explain why there might be a need for different diameter threads (if this is the adjustment), how you would measure the difference and thus adjust the die accordingly, and why there is no equivalent adjustment for Taps (although here I can see a manufacturing difficulty)?

Thanks John - and for pointing out my possible "search" error. Now to start making one.

Good idea - but where exactly are the free plans? When I did a search for Rod Bending Tool - the MEW search engine produced no results.

Has MEW or anyone created plans for a general purpose Rod Bending Tool for metal rods between 5mm and 10mm?

Hi Thor,

Yes - that's about the size of bearing I was thinking of. And the use of nylon for aluminium as well. Although I'll try and get similar size ID bearings to standardise on the fittings.

Thanks Gordon. As I only have a mini-lathe, my work-pieces are not very large. I was just going to add bearing races to each of the standrad fixed steady arms - with the aim of reducing friction on what will be, as I said, small diameter pieces. More experienced lathe operators than me might just find my reasoning a little naive - so I was just sounding out what other people thought.

I'm thinking about modifying my mini-lathe (Amadeal CJ18A) fixed steady with roller bearings. My question is: is there an optimum size of roller bearing for such a modification (i.e. large or small bearings) or would a whole series of bearings differing in outside diameter to match the diameter of the workpiece be more suitable. You evidently can't use large diameter bearings on small workpieces as the bearings would come together before the workpiece was enclosed.

Perhaps being a novice, I find "parting-off" to be the most imprecise, "fingers-crossed and hope" operation on the lathe. I've given up with it. I now just cut a V-groove where I want to part off - to a depth that provides a guide slot for a hacksaw blade to run in, and then just gently run the hacksaw back and forth while the lathe is turning. It works - and I know it will work every time - and the finish is good enough to only need a light facing-off if necessary. Because the V-groove operation works so well - I'm thinking of grinding a V-point onto the front edge of a parting tool to see if that makes the classical method work better for me.

I agree - but it wasn't meant to be a fair test - just one to see what effect occurred. The 24 hour period was one of complete closure of the workshop - so variations to the machinery or even the internal air mass were kept to a minimum.

But I know from experiments I established in west Africa to look at where mosquitoes were most likely to settle inside the local mud huts - just mapping the internal and external temperature and moisture regimes involved logging 30 thermistor/humidity sensor pairs, as well as other external weather parameters using automatic multiplexed loggers over a period of a month. It took that long before I had any idea of the variation caused by internal responses to the local external environment in what are traditionally and superficially very cool and dry habitations. Despite the open nature of these huts - there were pockets where temperature and moisture were markedly different to the overall average.

Following my purchase of a "Root-It" horticultural heating mat, I did a little experiment:

Placed the 9W "Root-It" horticultural heating mat (25cm x 35cm) below my Lathe (but not in contact with the lathe) and covered the lathe in a thin cotton sheet. Left the adjacent Milling machine without a heating mat and uncovered. Left the workshop to acclimatise over 24 hrs. Then applied a thermocouple to the vertical column of the milling machine - which recorded 14 deg C. Applied the thermocouple to the bed of the Lathe - recorded 17 deg C. So looks like even a low wattage mat and slight insulating cover has a positive effect in raising machine temperature above the ambient workshop temperature.

Did a little experiment. Placed a 9W "Root-It" horticultural heating mat (25cm x 35cm) below my Lathe (but not in contact with the lathe) and covered the lathe in a thin cotton sheet. Left the adjacent Milling machine without a heating mat and uncovered. Left the workshop to acclimatise over 24 hrs. Then applied a thermocouple to the vertical column of the milling machine - which recorded 14 deg C. Applied the thermocouple to the bed of the Lathe - recorded 17 deg C. So looks like even a low wattage mat and slight insulating cover has a positive effect in raising machine temperature above the ambient workshop temperature.

Thanks also to "not done it yet" - I just love it when a topic pulls in observations that didn't occur to me - and I would ordinarily have no reason to find out. The information about beehives is such a topic.

Hi Dave - this is unfortunately the problem with any form of article. The only way round it is peer-review - which as an ex-scientist, peer-reviewer and journal editor - I know only too well as being too lengthy and time-consuming to be used in hobby magazines. I just hope that any opinion I may offer, and the style in which I give it, does not come over as criticism - just clarification.

Just like to point out, for anyone who has followed SillyOldDuffer's advice to put a vent low down in their workshop because moist air is heavy, that this is wrong. Many people make this mistake because water is heavier than air. But water vapour is not. The molecular weight of dry air is 28.966 g/mol composed of the various % constituent values of Oxygen, Nitrogen, CO2 and the other minor gases. Water vapour molecular weight is 18.016 g/mol (2 x Hydrogen + 1 x Oxygen =2 +16). Without this fact - evaporation from the Earth's surface could not occur to form clouds. Incidentally, the base of cumulus clouds shows exactly where the atmosphere's "dew-point" is. Clouds are not water vapour but small water droplets held in suspension, despite being now heavier than dry air, by turbulent buoyant mixing forces inside the cloud. Only when these small water drops coalesce into drops big enough to counter the turbulent buoyancy forces do they drop out as rain. Mist and Fog at the surface form - not because they are heavy but because there is a temperature inversion, with air higher up being warmer that that close to the ground - so packets of moist but cooler air cannot rise into the atmosphere. Eventually the water vapour concentration rises to the point where the dew-point at that concentration is passed and the water vapour condenses to form Mist or Fog.

Thanks for all the suggestions. I did do a search of the forum before posting but nothing came up.

This all came about through building a new workshop at the bottom of the garden during those recent cold and wet months of Jan-March. I modified the 12 x 8 wooden shed from Dunster House with polystyrene insulation to all walls, doors and roof, all surfaces then covered with heavy duty polythene sheet vapour trap and then complete hardboard covering on top of that. Much advice was gained from MEW's bookazine on creating and equipping a workshop.

But the build, inevitably during this wet period, introduced moisture into the interior space as I made stand-alone benches and shelves, etc for the equipment - mostly through walking the moisture in on shoes. Now the good weather has arrived, the shed interior will dry out to ambient levels of moisture. I then plan to use a low power greenhouse heater (30W) as a continuous shed heater and use Aero 360 Moisture absorbers to dehumidifiy the air continuously. But with the large thermal mass of lathe and milling machines, early morning hysteresis effects might still allow condensation onto the exposed surfaces - so keeping those machines slightly above ambient internal temperature might help.

I take the point about the other metal items around the workshop - and I may well position the greenhouse heater in close proximity (or even thermally in contact with the storage box) to those items. They should then act as a storage heater as well. Compared to the electricity I use for the rest of the house - even a few more 30W greenhouse heaters (probably on daily timers) will not make a lot of difference.

As my workshop is a combined metalwork - woodwork area - a problem I now face and need to resolve is dust. The workshop is arranged so that all the metalwork machines are at one end - and the woodworking machines at the other end. Simple curtains spring to mind - but there may be better solutions that MEW colleagues might like to suggest.

Great idea - and I've got several of these saved from historic breakups of old electrical equipment. Will try them out. Their physical size is the problem - the heat will be concentrated over a small area which may take time to propagate through the machine which may cause differential expansion problems. You really need heating over a large area to avoid this - this is why the heating mats seem like a good idea. Anyway - I've bought one (250 x 35mm) and will comment once it arrives on whether they might fit the bill.

OK if the machines are inside cabinets - my workshop just isn't big enough for cabinets. But nice idea - providing the neighbours didn't think I was growing cannabis in my windowed workshop.

Adding to my post - I've just discovered heating mats for uses such as reptile tanks, pets, hydroponic growing for sale on Amazon. These may be a better option than industrial grade heating tapes. They are self-adhesive, waterproof, cheaper and easier to install than the industrial heating tapes.