Member postings for andrew lyner

Ah yes - "jack screw" finds the sort of thing I am needing on Google. But what I am finding tend to be on the big side. It would be nice to use it for pieces of one or two cm size that could be subjected to some serious forces (not just hacksawing) And on my mini mill, vibration is always with me and some good balancing in the milling vise could help with that.

"A none issue in a workmate - there are 2 screws just balance the loading." oh yes of course - silly me - we do that all the time with a workmate. I need 'that other screw' for other equipment too.

My main problem is on my metal bandsaw which is held by a clamp with a single bolt. Short pieces cannot give a balanced load and something of identical size needs to be put at the other end. That saw is magic and it leaves a smashing finish with a good square cut. If I could use it conveniently and more often, I would be very happy.

This must be a common problem. You have a small object that is held out to the side of a vise. You do the vise up tight but it always worries me that there's a tremendous asymmetry / twist to the load on the guides and vise frame. I often rummage around for a similar sized piece to put on the other end of the jaws and, when both pieces are held firm, I reckon I'm saving the vice from needless damage. (Ditto my Workmate.)

It would be ideal if I had a small screw jack to balance up the load. I have tried a pair of thin, reverse-tapers and that works. But is there a specific name for such a device? I'd like to have a look at some alternative approaches - or even buy something.

Every one of you who read this will have had this problem to solve. Problem is that it crops up half way through a job and never really gets my full attention.

"There's got to be more to your problem than 0.6mm end float in the nut to account for a whole turn of the wheel to take up the backlash."

One mm is 1.5 turns iirc so that 0.6mm talks directly to the drive.

This afternoon, I took a 1.5mm copper strip and beat it out to around '.6mm and cut out a D shaped washer / shim. With a bit of persuasion, I got it down in the slot with the nut and it's pretty rigidly home. That seems to have taken care of the backlash for the moment. Time will tell if the copper will creep; it was work hardened after the final annealing and bashing sequence and there is no deliberate movement in there (not any more there isn't). As no one has suggested a possible problem I will leave it in there and see how it goes.

Like / dislike / informative / skeptica / glooml etc etc buttons are all available choices and the designer should consult with users and tell 'em what he's going to do.

The need to have an album for your images is crazy; that (in the same way that the lack of a like) leads to more effort and confusion. The software was clearly designed a long time ago and many of its features show it. Strange that members are pleased to accept useful new machine technology but are shy of making use of good innovations in the IT direction.

There are so many helpful and knowledgeable members on the forum that I don't let it bother me too much.

"Old??" I wonder what the average age of members is. I am up there with most of you. I suspect - but I did start using computers some while before Personal Computing was available so I refuse to le IIT intimidate me when I need to use it and I do appreciate applications that are done properly.

Already, I have found places in this thread which would have suited a 'like' but not a full reply.

Edited By andrew lyner on 01/10/2021 20:20:42

I have been chasing some annoying backlash on the x axis (in particular). There is an annoying snatch at times and there is about one turn of the wheel to take up the backlash.

I took off the table and looked at the D shaped brass(?) nuts. The Y axis nut is well jammed into the apron(?) but the X axis nut has about 0.6mm slop in it. (See attachment).

I was proposing to use a brass shim to eliminate / reduce the slop. Any reason why not? I can't see how that nut can have become loose as there are no signs of damage on it. The previous owner was presumably making do with how it came from the factory.

I have moaned about the creaky nature of this forum software. It really is pre-historic. For no apparent reason it has rotated the image and. of course. the way of actually getting an image to sit here is particularly arcane. None of the other fura I use are quite so archaic - but last time I suggested improvements (e.g. a LIKE button), existing members jumped on me.

Drag and Drop is not a new-fangled idea these days.

I did wonder about that. They don't seem to sell them, though. But, go ahead; wax lyrical.

There are loads of diagrams showing how to grind lathe and milling cutters. However, the tool in a fly cutter is held at a (fixed) angle from the horizontal. The angle specified for the bottom face always seems to ignore the tool mounting. Is this because all fly cutters have the same mounting angle?

Funnily enough, because the work has a flat surface, it's very convenient to see and measure the actual bottom clearance so why isn't that angle quoted (in my experience)?

I have always found that the face angles for a fly cutter are actually easier to appreciate and make more sense than angles on other cutting tools.

HAHA. Been there, done that. They are all well short enough now!!

That could be useful information. Thanks, I'll have a look. I didn't make the point that I have three units (XYZ) and they all seem to be the same. I will have a fiddle and see if they will loosen up a bit.

It's not drastically stiff - just more than I would expect and worse than my digital calliper - and it's always worth casting a stone into the ME pond for ideas. I did read a comment somewhere of a version of the DRO slider that has a bracket on it and there were doubts about how strong it is.

The option against lubrication confirms my opinion.

Compared with my digital calliper, the DRO slide is fairly stiff and there is stress on the coupling to the table. I've made the coupling fairly rigid but it worries me that it can become loose. (= backlash, eventually)

The units are Shahe style from Arc Eurotrade iirc and I'm wondering if I could use some lubrication on the rails. Or, is it possible to loosen the 'grip' by reducing tension in the screws between the two halves of the slide? Lubrication could gather grot, of course.

I get the impression that several people have used these cheap DROs and I imagine it's a common concern.

That's a lesson learned for me. Thanks.

It's obviously a matter of one more correction loop needed in my processes. I guess it's pretty much always a matter of finishing to fit in the end at 'our end' of engineering. Ford has a slightly different approach, working in hundreds of thousands of units.

From Jason B: "CNC machines have a feature called cutter compensation which can be used so that the machine automatically allows for an under or over size cutter." There you go. Nothing new under the sun.

Ok - makes sense until you say required depth was reached. I can see how the slot will be symmetrical about the mid line but the only info that the DRO has is the position of the centre of the cutter. If the edge of the cutter is not 0.125" then how do you know the slot is the right width? Or do you just measure it with a calliper? The DRO has usefully found the centre line but more information is actually needed for the slot width to be what's required, I think.

You have corrected for the cutter width. If this were computer controlled, then the result would not be right. (I know nothing of automated systems yet)

Edited By andrew lyner on 22/08/2021 14:49:30

So I fitted my new DRO scales and I thought I'd better buy an edge finder and totally eliminate any more accuracy problems. (Har har - not really)

Working to an edge is shown on many posts and they all seem to assume that a 10mm milling cutter is actually 10mm wide. Mine are not like that; there's always a significant shortfall for beastly all sizes that I own. e.g. my nominal 10mm cutter measures at around 9.8mm. My calliper is not suspect because the 10mm edge finder measures as 10.00mm and there are other things to corroborate it so it's not the weak link in my chain, afaics.

What do you chaps all do about this? A slot with my 10mm cutter is pretty much the same size as my measurements of the shaft and across the flutes. It seems to me that I need a calibration note for all of my cutters ???

That has all be useful chat and I took a lot from it, thanks all.

I ended up with the long scale across the front with aluminium angle sheltering it from swarf etc. It's certainly a bit tight to fit the slider between the shield and the lock screw.. I had to turn the screw down to fit (already modified from a lever to a gnurled knob)

I was pleased that my end product looks a lot like the photos that people have shown!!.

Trouble is the DRO unit is the same and the mill is a mini. Also I'm pushed for space and the front of the mill table is a vulnerable position.

That's an option that was my first choice but I really doubt there's room. I'll have another look tomorrow and see if it will fit.

Thanks.

Andrew

I'm fed up with trying to count the marks on the scales on the wheels of my Sealey 2502 and the temptation to everything 'by eye' is great!!! So I am getting three of the fairly cheap magnetic DRO scales with remote display that Arc Euro sell.

The 2502 is more or less the same as the Seig models and the Arc Euro parts seem to be the right sort of size to nestle in, out of the way. But I have a slight dilemma which anyone who's done the same installation would probably have an answer for.

The short one I have bought fits the X axis with no problem or modifications and a long enough one (Z) will fit the vertical column in a position just behind the operating lever with a bit of a spacer involved. In both those case, the scales will be stationary.

However, the Y scale is the right size to screw onto the Y table and the slider will need to be fixed, somewhere on the left end (away from the wheel end). Afaics, the scale will fit in without limiting the X movement as long as the slider is out of the way. But that only works with the concertina swarf guard removed. That rubber stuff actually gets in the way, even on its own..

So it seems that I need an alternative sort of swarf guard apron thingey. It's all a bit cramped round the back and things should really be kept below the level of the table to clear my milling visa when it's there. What would do the job is a guard that's fixed to the moving table, rather than the present arrangement that's fixed to the column - as normal.

A few photos would help me a lot - plus any comments about how well or badly your various systems behave. It would make me very grateful.

P.S. I should add that there are a number of videos which show people mounting DRO on a minimill but none of them seem to mention the problem of restricting the cross axis movement due to the DRO scale. IT's only 100mm to start with and ten or fifteen mm lost if you want to protect the dry from being squashed, that's a pain in the X axis.

Edited By andrew lyner on 28/07/2021 15:20:08

Gears themselves are very susceptible to damage by trying to engage them when moving relatively. Most car and m/c gear boxes are 'constant mesh' type, in which each pair of gears are constantly in mesh and a gear is 'selected' by sliding and using 'dogs' which lock together on a shaft and do not roll together as as the actual gears do. Dogs are very tough and will take all sorts of abuse - clutchless changing up or down used to be easy peezy. A chipped dog is no disaster. The plastic gears on cheaper lathes would never stand up to graunching at speed.

Let's face it, do you save a great deal of time by taking that short cut? It's not like trying to beat the next guy at traffic lights, is it?

I engaged a lady with an Indian accent for some while about some Microsoft security thing. Eventually she said "Wasting my time, bloody" and she rang off. Fifteen all, I reckon.

The 'snap' seems to vary from collet to collet and tool to tool.

Tightening the arrangement up with the holder not in the taper means I can sock it all up a lot tighter. I think that was the main cause of my problem. I may invest in a longer handled replacement for the C spanner supplied. AlsoI'll go for a ball bearing version of the Nut - if I can assume compatibility with the two ER25 holders(?).

BTW, I am aware of a fair bit of reaction against the idea of 'liking' posts with a single button press. This is a typical thread where I could well have wanted to give a brief approval to many of the above ideas but that would have involved explicit quotes of nearly all the posts with the resulting ten mile long post which so one would ever bother to read right through.

Sop here's ONE BIG LIKE and I was shouting this!

Wow. Thanks for that long list of things to look for. The "snapping" could be something that I am missing. There is a slight click but nothing very impressive that I can remember. I'll take more care and tighten it until my eyes bulge.