Member postings for Chris Heapy

Two bolts and two dowels locate the fixed jaw. It appears to clamp down securely when tightened down firmly, and I don't have a problem with that. It can also be repositioned in one of three places relative to the moving jaw to acommodate workpieces of different width - one of the features I found attractive. It is supposedly a British design made abroad. It is made well but I feel the design has fundemental faults (which to be fair I should have spotted at the outset). http://www.warco.co.uk/vices--vice-jaws/110-dh-4-precision-vice.html

As stated, the position of the screw is too low:

The rear of the vice is prone to filling with swarf so I made a cover for the gap:

Apart from the fact it doesn't work as a vice I was quite pleased with it...

I don't have any suitable lead sheet, but I have put a hard steel parallel in and tightened up on that and it's easy to twist it in the jaws - clearly it is tipping quite a lot. I will try shimming the the top of the moving jaw until I can't easily twist the parallel, then I'l remove the jaws and rub them across a coarse diamond lap to roughen them up. However, I've lost confidence in it and will always worry whether it will hold...

That was decent Clarkson 1/2" endmill, and the first time I've broken one that big. Broken plenty of smaller cutters but not 1/2" sized. The problem was caused by this new machine vice (below) which simply won't grip/hold anything. I'm not sure why - maybe a combination of the very smooth/slippy jaw faces and also the poor geometry of the moving jaw (which is very tall compared to the position of the screw). I had it tightened up very firmly after having suffered slipping workpieces before with it, but it just failed to hold the part and that caused the breakage. If I can't think of a way of improving it then it will have to go because I simply can't trust it.

Some progress on the ball turning attachment(s), I took the day off yesterday to go ride my motorcycle as it was such a nice day Today is not so nice so back in the workshop. Still not decided whether to make it a worm-driven thing (which is a bit slow in action), or gear and pinion driven, or just use the long handle option.

Made from mild steel section but with a gib-strip so any wear in the dovetail can be compensated for. This is one of those jobs where I rarely measure or plan anything, it's all in my head and I just cut away anything that doesn't look like a ball-turning attachment.

Edited By Chris Heapy on 03/05/2013 19:03:36

I've been using one of these for a short while. When I received it I was disappointed to discover the shank of the thing is made from aluminium rather than hardened steel, that may be OK in a collet chuck but it's liable to get damaged if held in a keyed drill chuck. I was also thinking it might be useful for aligning my mill head (or a long workpiece mounted on it) by making a little device something like a 1ft spirit level with a prism at one end and a line at the other. Any deviation from 90deg will be immediately apparent by a shift of the dot above/below the line.

Started on making a couple of ball turning tools for the lathe, only got as far as machining the dovetail slides.

Oh, I also fitted a couple of roller thrust bearings to the S7B cross-slide, still got 3 thou backlash - better than 10 though. Will adjust again after the bearings have bedded in a bit.

Edited By Chris Heapy on 01/05/2013 16:20:33

Andrew: I keep speed down for that reason, although the grinding paste I use is quite viscous and doesn't tend to get thrown around much anway. Can't tell you the RPM as I adjust it on the fly (3-phase/speed controler) but I would guess 800-1000 -ish.

Tell her not to worry, and you'll listen out for the doorbell for when she gets home...

I know, but the key word is 'finish' - the appearance of an engine-turned finish, which is quite different from using a cutter to form complex surface geometry which has actually been 'engine turned'. However, we are splitting hairs and the name is not mine in any case.

Bazyle: The finish described above is just that - a decorative finish applied to an existing metal surface, and has been called Engine Turning for donkey's years. Ornamental turning generally employs a cutter to produce a new surface, often in 3D, using complex geometric chucks or machinery offering similar funtionality. I don't know where you get 'Modern Marketing' from given its history, and it isn't a poor substitute for anything - it is what it is. Used appropriately and executed well it can enhance appearance (dependent on the eyes of the beholder of course). As mentioned above, it also has a practical application in improving lubrication of sliding surfaces.

No adverts at all showing on mine (Firefox), learn how to configure your ad-block and banner removal if it bothers you.

Absolutely right Rik - like the thread title says! In fact there are many other names too but I'm not sure if any particular one is 'right'

Thanks John, I had to Google 'Cratex bobs' described as 'rubberised abrasive wheels', can you say how soft they are? How long do they hold their shape/pattern? I've tried many things like this - but not those actual parts. For the ones that I used I found as they wear the pattern they produce 'softens' overall and this was noticeable as the work progressed, so later parts were less distinct than earlier ones. I also tried shaped pieces of hard rubber in combination with grinding paste, but the rubber invariably breaks down leading to an indistinct edge. One advantage of the brush is that it can cope with uneven or spherical/cylindrical work (provided the radius is not too tight) because it can flex a little. Also, the method is not reliant on abrasive integral in the rotating head so new sharp grit is always available to it.

Another consideration is the material that is being worked on - soft aluminium will respond to nylon blocks quite well, steel brush and abrasive being a bit harsh for this. Hard steel really does need the carborundum paste though (in my experience).

I must say your workpiece looks beautiful, so clearly your method is working well.

Edited By Chris Heapy on 29/04/2013 00:19:03

Edited By Chris Heapy on 29/04/2013 00:31:09

Plenty of info on the web about this but no threads on here that I can see. If you're a beginner you may not have heard of it but old hands surely will. There are many ways and tools that can be used to achieve this traditional attractive finish to smooth steel but I thought I would just describe the tools and method I use.

A jewelled finish looks like this:

Essentially a series of overlapping circles in a regular pattern. A photograph fails to capture the dynamics of the beautiful finish which moves and shimmers as it is turned in the light.

The pattern is ground into the surface of the metal using some sort of flexible head (rubber, synthetic, nylon, metallic brush..) as a rotating tool and some carborundum (valve) grinding paste. It is the grinding paste that does the work, whilst the head dimensions govern the size of the pattern. Naturally you will need some method of indexing the workpiece so it is moved in precise steps in X-Y axis (for flat surfaces) or x-rotation (for cylindrical surfaces).

The rotating tool I've found which works best is a small (5mm diameter) wire brush contained within a home-made holder which constrains the brush filaments and stops them splaying outward.

Only about 1/16" length of the filaments are allowed to extend beyond the end of the holder - and you will need to keep checking as work progresses because they will wear away fairly quickly.

This was my setup on my mill for the job shown above, with the workpiece held in a 3-jaw chuck attached to my HV6 rotating table. The mill bed takes care of the X-axis steps by way of the handwheel markings, whilst the rotational steps are achieved with the HV6 handwheel. It is an extraordinarily boring job to be sure, and one that could readily be done on some CNC machinery. However, need must... and the results are worth the effort.

In the picture above you can see the workpiece is coated in a generous amount of grinding paste (180-grit in this example), and the end of the brush is brought into gentle contact with it. Don't press hard! - it is not necessary and will achieve nothing other than premature wear of the brush head. Only a light contact is required, and In this particular job I counted for 15 seconds then released. (Did I mention this was boring...?). If you press too hard you can also end up with deeper scoring than expected and possibly a raised blob in the middle of the circle, either of which will ruin the finish.

Aim for an overlap of about 50% of the circle diameter in both axes, there is no hard and fast rule about this but that is a good starting point. Don't forget to keep checking on wear of the head, I had to re-set the depth once part way through this job. Oh, and make sure you cover all machine beds with rags or paper towels to keep the grinding paste off them - slideways and grinding paste don't mix well.

I suppose the difficulty of attempting this using a CNC setup is the loss of 'feel' which will normally compensates for any gradual wear in the brush head. A fixed depth setting simply won't work. I guess you would have to use a tool modified so it is weighted and able to slide freely (vertically) on a shaft - the CNC spindle will take care of the indexing just fine, the weighted head producing a nice even pressure (with exaggerated Z-movements when moving to the next step). Wish I had some CNC kit to experiment with

Just pottered about in the workshop mostly. I replaced the rubber slideway cover on the mill with one made from a rubber car mat.

The mat was being used as a cover for my surface plate, so I had to make a timber one to replace it:

...and finished off my modified depth stop on the mill too, it's hollow with an extendable rod that can hold a DTI, whilst the actual depth stop now has a thumbscrew with roller bearing so it clamps up tightly. Oh, and I had to make a replacement drawbar for the mill because the thread had stripped.

Edited By Chris Heapy on 28/04/2013 21:07:20

That may well be true, but the Mitutoyo display is also well recessed and far less likely to be impacted. I'm looking whether I can remove the shards of glass from the callipers with a view to replacing with a glued-in perpex insert of some sort. I've had 2 Jocal callipers for donkey's years that have been badly treated on occasion - dropped, knocked, stuff fallen on them... they have resolutely survived all.

I bought a relatively inexpensive 8" calliper recently which suffered an unfortunate accident, I smashed the screen! I had not even realised it was glass and a minor impact - the sort that can be expected in a workshop, broke it. It should not have been made of glass, and to make matters worse the screen is somewhat convex thus standing proud and the first thing that will make contact. A poor buy then...

A better purchase to help a pair of aging eyes was a new Mitutoyo mic to replace my 45-year old Moore&Wright imperial mic (which I bought new ) Not only does the Mitutoyo have a large, clear display, it converts between mm/inches, has 30mm capacity, and is very quick to operate - taking just 10 turns to cover the entire 30mm range.

Many parts like this (external radii) are more quickly dealt with using a combination belt sander/disk sander. It perhaps won't be as accurate as machining the part (depending on what tooling you have available) but if time is valuable to you then grinding is a good method. The finish is also very good. A rotary table with a chuck should also be high on your list of things to buy, you'll find it has many other uses apart from this type of work.

For the belt sander, make a proper table for it adjusted to exactly 90deg, and if you run the belt right up to one edge (and slightly beyond) it curves around the edge a little allowing tight radii to be formed. The disk sander (typically 6" diameter) is good for putting the final finish on the part.

This is a rather poor picture of mine, on the left, but you get the idea..

I don't know if this is an old trick or not (it probably is - few things are new in this game). Anyway, the job is to mount some bar ends in the chuck for facing, and you want them to run true, but neither end is machined so no reference point.

For this I use the 'bearing on a stick' method shown below. Simply, it is a ball bearing (extracted from a broken computer hard drive) mounted on a suitable length of square section steel, which itself is mounted into a tool holder.

To use: mount the workpiece in the chuck as accurately as you can by eye, do not tighten the chuck firmly - it just needs to be tight enough to hold the piece so it won't move on its own, yet able to be repositioned when the bearing is pressed against it. The photos are self-explanatory (I hope). Spin the workpiece slowly and bring the bearing into contact (which will be intermittant), then continue pressing until it runs true. The sound it makes is as good an indicator as any. Back off the bearing and tighten the chuck more firmly and re-check, if OK tighten fully.

By similar means the bearing trick can also be used to make thin-ish disks run true by pushing it up against it's front face, it just needs mounting along the line of the bed instead of across it.

Thanks Trevor. I chipped a carbide endmill trying to cut out the hardened area so I gave up on it. I note for future reference your comment about 'never pilot drill' because indeed that is what I did.