Member postings for not done it yet

BODMAS (or BIDMAS) is the mathematicians rule.

I’ve flashed the field coils on countless dynamos, over the years. Simple and works.

That stud looks suspiciously over-long. If out of sight, one could remove some thread at the end of that stud as a lead-in - and as Hopper states, put that fixing on first and leave the easy ones until later.’ Or even maybe altering the order of fitting the parts together?

Edited By not done it yet on 14/06/2018 06:09:11

Eugene,

I am inclined to disagree with your statement that it is a one piece casting - unless you. are carefully ignoring it consists of a casting and a machined item It looks like those four fixings are securing a back plate to the main casting, Removal of those fixings may reveal how the screwas were fitted?

Nige,

Why design your own? There are plenty of working designs out there already and yours will likely mirror one of those already existing - or maybe a combination of several. Some are better than others and yours may well not be as good as the best out there.

Make your own, by all means, but my advice is to choose a design which is proven to work (popular reiews) and get on with it.

I would be using easily purchased, good quality, reliable wheels from a good supplier. Making those as “few offs” is neither cost effective nor easy. Replacing, or adding, wheels later would be simple - and a lot less hassle than making your own to exacting standards.

Your choice in the end, of course, but that is what I would suggest. Re-inventing the wheel has been done umpteen times, but few have bettered the basic age old design of a circular rim running on an axle!

Just look at a practical scenario - that of one man moving a large plane on a flat runway. Simple, when one thinks about it.

There is no weight on any flat track in the direction of the applied force of the engine. Gravity works perpendicular, so towards the centre of mass of the Earth. It is only the friction between the track and wheels that provide anything more than the inertia of the load to get it rolling and to accelerate.

The load will accelerate according to Newton’s Second Law of Motion, once the static and rolling resistances are overcome.

As Duncan says, a snatch force will be greater that the simple tractive effort fom the loco. Laws of momentum come into play on this scenario.

Look up f = m*a and m1*v1 + m2*v2 = m3*v3 in respect of the two laws.

Remember the track with one end elevated to provide constant velocity, when doing experiments to demonstrate Newton’s Second Law at school? Or perhaps recall experiments with a linear air track? I do.

Mick,

My reply to the other thread, that was censored yesterday, was that I would not be wanting one of their gift cards but would certainly not turn down a gift card from Arc EuroTrade if they ran a similar scheme.

Ahhh, so not really an ‘aerospace quality’ thread at all. Nick’s reply above might have answered the right question at the first post.

Mick, you have a PM.

Here is a rough draft of what I would have posted on your censored thread yesterday evening.

“Some good, some rubbish. They ony sell for others - a collective of possibly lower quality, or failed as first quality.

Just don’t spend money that you can’t afford to lose as their customer service, IMO, is rank. They will try anything to avoid putting things right for the customer.

I bought a set of ER32 collets through them. Collets are OK, but the morse taper on the holder was not a morse taper - it touched at the inner end and basically waved in the wind at the cutter end, so could have damaged the socket as well. Their customer service was total rubbish. You won’t know how bad it is until you need some service.

Another item was a dial indicator. The fit of the supposed dovetail connection was useless, but the item was good apart from that and it did not really bother me as it is held with an alternative fitting.

There were loads of complaints re their ‘burning’ lasers not burning anything. Some are almost certainly bonafide complaints. Mine was much improved when I fitted a collimating lens and works well for the intended purpose - now.

Your choice, your risk. Cheap and cheerful. They are buying the advertising sevices wherever they can - as long as the reviews are positive. Emma Ritson gave an honest review of a set of angleplates and has not been asked to do any more - just too honest. The angles were OK, but they would not stand upright on a horizontal surface!

Doubleboost, xynudu, mrpete222, chrisb257 and a few others on u-toob are getting loads of free items. Look for what they don’t say, rather than the positives they keep plugging. I would not want a set of angle guages if they would not stand perpendicular on edge. My machining has enough tolerances without more introduced by cheap under-spec tools.”

SOD,

I think half a dozen Apache ‘copters might have made a considerable difference on the Falklands!

Admittedly a bit before their time, but, all the same, if the Atlantic Conveyor had not been sunk there might have been more choppers (particularly Chinooks for heavy lifting) that would have played a very positive role at most stages of the operations.

Whoever allowed the container ship inside the aircraft carrier line (so within range of enemy aircraft) missed a trick on that occasion, perhaps? Or perhaps the Atlantic Conveyor was not designed for operations in the lower half of the ocean!

I think I covered that in my post above. That is where the ‘precision’ would be applicable to this device. Your OCD is concentrating on one aspect that is not important.

Further to my post above, consider the forces between the vise base, the movable jawand the the screw. The screw will attempt to always drive one side of the movable jaw upwards and the other downwards, altering the frictional forces between the jaws and bed. This is likely what is causing one end to advance more quickly than the other. Try loosening the jaws - you may well find the opposite action in that direction!

350W motor.

900m/min cutting speed!

IF the band has about 4tpi, it is most certainly not for metal!

Wouldn’t a simple triac be the norm?

I would suggest you search out aero kit suppliers if you require this material for anything that lifts a human off the ground and into flight. It will likely require all the certification that goes with aerospace usage.

I think the ‘precision’ was referencing the angles of attachment to the drill press table.

Does it lay flat and parallel to the table? Does it hold workpieces perpendicular to the table when fixed in the other planes? Does it hold items correctly and firmly?

It is a drill press vise. I would not be expecting to need a soft wire, or other aids, to clamp a workpiece square with the fixed jaw - like needed for a milling vise (even the precision versions of those).

Does the jaw pivot easily by hand when close tho clamping? I would always expect an unguided jaw to always have one slightly looser side than the other. Look for its good points, is my advice - not the unnecessarily picky parts of its operation.

Nearer £200 if paid via paypal!

Edited By not done it yet on 09/06/2018 19:35:56

Three screws? Am I missing something?

Great job. I will stick with my hobby lathe!

Even a grub screw, screwed into a dimple in the blank end would do. Easily removed if ever necessary. The loctite will likely never move and the extra is just insurance - costs little and gives peace of mind.

Guessing you are going to fit an ER collet holder in the hole? No reason, if you want ‘belt and braces’ security, for not drilling and pinning after the loctite has cured (not before - or the piece may be pushed off-centre).

The technique is the same for 1/4” as for 1”.

Practise on small diameter bolts or scrap rod pieces is my advice. Far, far cheaper, but will need a supporting centre, to afford more rigidity to the workpiece..

Of, course, for smaller thread forms, there are specific 90 degree feed type cutters, rather than the historical ‘cut on one side’ cutting technique.