Member postings for not done it yet

He's not curious, but probably cautious. Likely previous experience?

A thread on the performance of our athletes has, regrettably, sunk to the level of pros and cons of watching the Google box. We don't have one, don't want to want endless drivel on a small (or large) screen.

That makes no difference to the performance of our olympic athletes. They have already done superbly well. That is whether you might watch it or not. Remember, topic is their achievement, nothing else. If you want to winge, make a thread and see how much interest you get.

It's likely not so much an improvement. Our athletes do the very best they can, often being disadvantaged in comparison to other nations (for more than one reason). They are clearly some of the best in the world and maybe got on so well because of the anti-drug system improving so much, recently, thereby removing some undeserving competitors from the Olympics.

A dedicated bunch, and they deserve every medal they win. And all the rest of the team can be proud to have even represented their small country at such a high level.

A good repair and well done for getting it done!

I note the statement 'I sobered up a bit'. I hope it was not caused by machining while 'under the affluence of incahol' Or did It drive you to drowning your sorrow?

Even the best (that doesn't include me, btw) occasionally need to make repairs. Keith Fenner recently had a 'slip and climb' mistake to repair on u-toob. My most remembered failings in the past is that of making two of the 'same handed' items, even (or especially) after knowing they need to be of 'opposite hand'? Now that is annoying for me! Especially if they need to match exactly, dimensionally,

Duncan,

I'm m with you.

The one and only positive for changing back to Imperial is in thread cutting imperial thread forms. As you say, better to have learned metric - sooo much easier! Imperial measurements are only useful for converting imperial drawings to, say, 1/4 scale as far as I can see. Any particular length, area or volume will be the same length, area or volume whatever units one might specify. It will not change just because one calls the units something else.

Most 'imperial ' bearings have been metric ones for years, the Americans reportedly missed Mars with one probe due to someone using an incorrect factor for converting their units to metric (yes, space travel calculation/iterations are done by computer using metric numbers, not feet and inches!). What about degees in a circle, for instance? Used in both systems but derived from what? Multiple factors is one suggestion. Perhaps we should adopt radians or even astronomical space unit these days. All have their place in science, but some are better than others in different fields. Railway lines - the width of two horse's rear ends? The furlong - how far a couple of oxen could drag a plough before needing a rest (while turning around). Even the Fahrenheit scale of temperature was a current unit, at the time, adjusted for a different zero point (which does not hold true innthe light of scientific development - zero Fahrenheit is no longer the lowest temperature attainable).

My lathe uses Imperial scales, but my vertical mill is metric. Makes no odds (apart from screw cutting) when dro's are fitted. Remember, too, that 'thous' are metric in nature (powers of ten).

The power requirement is a function of mass flow through the pump,

Not quite true. The amount of fluid pumped will depend on the head. At maximum head, the pump will provide no flow but will still consume power. The stated flow rate is likely at zero head, hence a high figure for prospective purchaserscto ogle over! Impellor pumps are notoiously inefficient once off the pumping curve. Water providers now save huge amounts of power by speed regulation, rather than throttling the output.

Actual power used will be a function of running the water pump plus mgh, the potential energy imparted to the water, where m=mass, g= gravitational field strength, a h = the lift height. Values in SI units, of course. At maximum lift, the mass of water pumped will be zero.

Presumably for vertical milling? Does it have a drawbar? If not it is only useful for drilling as any side thrust forces (particularly intermittent) would loosen the tooling, with potentially disastrous results.

Only guesing, but he horizontal arbor appears to be held in place by the support centre and not by a dra

wbar. S

o unless the shaft(s) can be bored/arranged for a drawbar, it is only a horizontal mill with drilling head. Good piece of kit for small jobs, mind. I like old iron.

Probably not so worn due to its restrictive use, I would think. Horizontal mills are not so popular as vertical ones because they will not carry out such a range of duties, but they are certainly better, by far, for those they were designed for - think here flatting a surface (for squaring up a block?), where each pass is always flat to the previ

ous, provided the table and cutter are parallel (vertical mills need to be perfect in all three directions).

mandrel handles are one of those things which seem to be essential equipment for model engineers,

I'm in Duncan's camp. I can turn the chuck by hand, if really needed, for starting a thread with a manual tool. Apart from that I use the lathe motor. My LJ turns at a reputed 36rpm minimum in back gear and a lot less if I reduce the motor feed Hertz. Who could want it any slower than that?

Can't help, but will just ask what is wrong with the crow bar and pipe roller technique? It may be slower, but cheap, effective and no time constraints on the job.

I fitted a self centring chuck to my rt, but in hindsight, an independent 4 jaw would have been better for accuracy. It is the part that needs centring, not the chuck. A dti should get you closer than a chuck with run out. More trouble, perhaps, to centre with an independant jawed chuck, but how often is it used? And odd shapes can be accommodated. Win, win for the independant chuck, I reckon.

Depends on what you wish to thread. If it needs to project down the mandrel, the options above are good. On the other hand, if none need to be mounted further back than the chuck jaws, a threaded taper sleeve at the chuck end of the mandrel will suffice, the handle being tightened to the mandrel by a locking nut on the drawbar. Nearly all lathes will take a centre for turning between centres, so it is unlikely your lathe mandrel is a parallel tube?

I note you gave much more inf

o on another forum. I would not recommend reducing tool dimensions without very good reason. Later overloading of the machine or tool is one risk, often forgotten after the initial change. Prolly not applicable to this machine-tool combination, but people do change machines....

With regard to hardness, the Rockwell scale is one of several and relates to the ability of the surface to resist abrasion, surface denting, etc. Generally, the harder the material, the less resilient the object is to bending - really hard offerings of the same material will be brittle at high hardness - tools/items can easily shatter if struck too

hard. There needs to be a balance between hardness and flexibility for most items, dependent on application. Shanks are often hardened to avoid damage from chucking.

Go with carbide for easy turning, but surface finish is important and may be a problem. XD351 is likely spot on the money. Using tools too big for the machine is attractive, but not necessarily a good move. Reme

mber, by reducing the diameter by 33% means removing more than half the metal in the shank....

Climb milling or conventional? I might just understand the failure, if the former.

Doesn't look like a very wide contact area for those wheel teeth (only a small diameter worm?). It strikes me that perhaps the worm is fully hardened and rough, while the wheel is in a softened state?

Not a lot of point for a rotary table if it must always be locked down - might just as well use a simple dividing plate?

Cliff,

There are options to continual shimming.

Make a shim (or pack) for each tool.

Get, or make, more tool posts and retain tools fitted, ready for use.

Not sure about fitting any particular QCTP to that lathe, but no need for drilling, I suspect (a waisted central bolt would be adequate?). Often changes need to be made to fit them, but usually this can be achieved without modifying the lathe top slide (Ie change the tool post fitting to suit).

An even cheaper method is to make a table or graph of Hz versus speed (just like a screw cutting chart?). You will soon find that belt pulley changes are rare and you will easily remember the usual speeds at different Hertz. Anyway, do we need to know the real actual exact precise spindle speed to the odd rev per minute or so?

I fitted a simple hall effect counter on my LJ, but rarely take any notice of it. Cutting depth and traverse rate, along with surface finish and how the lathe 'sounds' is far more important than setting it to an exact rotational speed.

Do start by turning a rigid bar only held in the chuck. No amount of off-setting the tailstock will make any difference if the tool position is changing as it traverses the ways. Perhaps tell us what this bed length is and how the lathe is supported? Flimsy timber is a no-no, timber is not that good, but a sturdy steel stand on a solid base is good.

Don't assume anything. All that is likely to do is lead you up a dead end!

Are the locking 'devices' free or tight?

for a new cross slide that im getting made

It would seem to be a sensible suggestion that the maker of your cross slide supplies the screw?

nothing too complicated to set up .

The complication is simply that of disconnection so that the manual feed wheel can be used. Most are satisfactory at slow feeds, but fast traversing is not always fast enough.

Most could easily be converted if the manual wheel was removed and replaced with a power drive. But shifting the table by a tiny amount might be problematic.... Clearly, tables with wheels at both ends are easier conversions and retention of manual adjustment is necessary.

Just wish I did not have to learn via my wallet

Sam,

A fact of life, on occasions, I'm afraid. Nobody but the user knows what their machine is capable of. Large rigid machines will always cope with higher feed rates than a flimsy chinese hobbyist import which may not even be adjusted optim

ally.

25mm per minute would likely be OK, but selection of cutter type is covered, no doubt, in many tomes.

There are well documented surface cutting speeds for machines, but many machines are unable to achieve the advised cutting speeds. Yours did have a higher speed, which you apparently forgot about. Cutting speeds assume the optimum for everything else on the machine.

Different materials have variable cutting characteristics. Aluminium is well documented as requiring much faster surface cutting speed (than steel) and possible difficulties. One is the recommendation for use of some cutting fluid - like WD40 as a popular choice.

Melting point of the mateial being cut is yet another factor. Cutting dry requires steadier progress than lubed cooling. Aluminium, while having a good heat conduction rate will still have a higher temperature at the cutting/shearig point. one possible reason for it 'weldig' to the cutter tip.

I have often made mistakes, sometimes to the detriment of the cutter, sometimes of the manufactured item. It costs time, if not money.

I keep bees and find it soo easy, but many (mainly those with insufficient learning and non thinking) struggle and call it a 'dark art'. But machining metal is far more challenging than wood, per eg.

Think yourself lucky that it only cost you a 3mm cutter. It could have been far more costly!

I went to the show at Donny, this year. The one thing that struck me was the load of cheap unbranded cutters available at supposedly bargain rates. I know that buying cheap often means buying twice, so ignored these so-called 'bargains'. From my woodworking experience, I know that the right tool made of the best material and sharpened properly will work so much better, and longer, than lower quality tooling.

Many will claim high cuttig speeds, deep cuts and/or high metal removal rates. Most of us are much more conservative because our kit is less sophisticated, not so perfectly set up or we are not so highly experienced in selection and operation of tooling and kit. I have long used carbide router cutters for timber, but recognise that not all carbide cutters are equivalent. I bought this my first solid carbide milling cutter at Doncaster and I will use it very carefully, given the cost differential to other similar cutters in other materials.

Experience does cost. Learn from it and move on. On your last posting, consider what might have happened if your 3mm cutter had, say, twenty cutting edges instead...... would it have been better, faster, etc? I think not.