Member postings for Jon Gibbs

If you left a concentric stub on one the faces of the cam you could use a dial indicator in conjunction with your 4-jaw to set the offset from the centre-line precisely correct before facing the stub off and boring through. There'd be no need to scribe and mark up the face first. The TIR is simply twice the offset.

Of coarse if the cam is big enough to project from the jaws then there's no need to use the stub at all.

HTH

Jon

I'm struggling to understand the requirements exactly but a cheap solid angle plate (3" x 3" may be big enough) with a couple of lengthwise keys could be fitted onto the T-slotted area of the ML7 cross-slide and bolted down with t-bolts.

With the angle-plate in-place you could bore it through to locate a drill chuck taper or threaded stud turned on the lathe.

HTH

Jon

+1 for homemade levelling blocks. You'd be very fortunate to get it level enough to turn parallel without them.

Mine have M16 bolts bored to accept M8 or 5/16" bolts from underneath the lathe.

For an ML7 the key dimensions (Courtesy of Wiktoria Jablonska (Anna) from the Myford forum) the rising blocks are on 4 5/8" centres and lengthwise it is 22 1/4" between the holes.

HTH

Jon

+1

It prompted me to send for some cheap Chinese toolholders, boring bars and inserts from eBay that came just before Christmas. They've proved to be pretty good.

Jon

+1 for bearing nut closer & +1 for holding the top pulley/belt

but if it's still tight I sometimes use the draw-bar soft hammer to tap the end of the spanner to slacken off the collet nut. This technique is needed more often for my Clarkson and Posilock chucks with plain closers.

The inertia and belt gearing effect usually provides enough resistance to work.

HTH

Jon

Edited By Jon Gibbs on 11/01/2018 09:39:21

Reminds me of my Dad who was a country bobby in the early 60's complete with pushbike. One day on his regular beat he came across some blokes with the road up and a gas main in the bottom leaking profusely through a hole. The blokes digging the hole didn't know what to do except wait until the gas board arrived. Dad, who was always eminently practical, took a look at the size of the hole, got out his pen knife and whittled a bung out of a green stick from the nearest hedge and managed to stop the leak until the gas men got there.

To be fair, it's not just the Sun, it's being almost universally reported today.

At 70,600 tonnes she'd take 40 years to sink at that rate if they left it

Edited By Jon Gibbs on 19/12/2017 09:31:22

I read this and thought it must be a huge leak.

...but then it boils down to it we're talking a litre of water every 15-20 seconds through a prop shaft seal.

If that's the worst they can find then the new HMS QE must be bloomin' great!

Jon

+1 for Emgee's comments - I don't think you'll notice.

If you want the tooth load on your slitting saw to be equal (and assuming it has an even number of teeth) you could always take a Dremel and remove every other tooth

Jon

I can use 10mm CCMT holders in my ML7 with a good quality Dickson QCTP holder.

Chronos and RDG sell Dickson QCTPs or you could buy a Myford (also RDG) at a premium but the quality is IMHO better. Some of the cheaper import holders have an overly thick lower shelf which restricts the size of tooling but if you keep these for boring bars and other accessories you can save some money.

There are some CCMT 06020X TCT holders and tips bargains from China on slow boats (Make sure your order is under £15 to save on VAT charges) on ebay.

HTH

Jon

In all of the photos I've seen the hatches appear to be positioned fore and aft which would suggest that the cupola was fixed but there appears to be a bit of a discrepancy between these photos...

which seem to show the view-port facing slightly rightwards (first pic) or directly forwards (2nd & 3rd).

So, it's hard to know for sure.

Jon

Edited By Jon Gibbs on 15/12/2017 15:26:27

Edit: Ahhh, Wikipedia says... "The Mk VIA had a return roller removed from the top of the leading bogey and attached to the hull sides instead, and also possessed a faceted cupola.[7] The Mk VIB was mechanically identical to the Mk VIA but with a few minor differences to make production simpler, including a one-piece armoured louvre over the radiator instead of a two-piece louvre, and a plain circular cupola instead of the faceted type.[7] "

So, perhaps the VIA faceted cupola has the two viewports (picture 1) whereas the VIB has the one viewport facing forward. 

Edited By Jon Gibbs on 15/12/2017 15:32:59

Looking at the spindle diagram on lathes.co.uk the recess is clearly there. It seems quite a reasonable idea for completely preventing any possible MT slippage(?).

It might be sacrilege to suggest this but if the MT3 is simply recessed you could turn the square recess off (or at least reduced in depth) the spindle nose with a TCT lathe tool clamped to the milling machine bed?

Jon

...but we're not talking about trading either a musical instrument or a historic artistic artefact here. The OP wants ivory to restore an antique item.

Jon

Not sure whether it's come into force yet but all ivory trading may be banned - at least in theory...

**LINK**

Depending how small the pieces are, I'd suggest either tagua nut vegetable ivory **LINK**

or artificial ivory/bone **LINK**

Plentiful supply and cheap enough.

HTH

Jon

This is all interesting stuff but I'm afraid FF that just because an equation that has been reproduced several times doesn't mean it's correct.

It's 39 years since my A-level chemistry but this is pretty basic stuff. A solution of anhydrous citric acid in water is just going to be a dissociated mixture of H+ ions (this is the definition of an acid) and citrate ions (C₆H₅O₇-). All acids will dissolve rust (and iron/steel) and this one is no different. It's a fairly weak acid but will naturally react with the rust reducing it to a mixture of Fe2+ and Fe 3+ ions and citrate ions, liberating water or hydrogen in the process. The iron citrate will then potentially precipitate out, depending upon the solubility of the iron (II or III) citrate (**LINK** and **LINK**), which are both only weakly soluble.

Citrate ions are stable, and so is iron citrate in both forms, and so I agree with Martin that it is highly unlikely that the citrate compounds will decompose and release carbon monoxide.

Jon

I'm quite surprised to see the equation quoted above for citric acid action on rust. What's it's provenance?

It's a while since I did A-level chemistry but surely, one would expect at least some iron citrate created (C₆H₅FeO₇) with hyrogen and water only liberated.

Jon

I take the point that chalk is "close-enough" for some jobs but surely the advantage of the DTI is that you can determine, based upon the job in-hand, when you get "close-enough". Just because you can measure to within a thou, doesn't mean you can't stop adjusting when you get within 10 thou.

MrPete222 posted this in the last few days for a really snazzy DTI holder **LINK**

Mine uses the stem to mount the DTI which has the advantage that if I have a lot to do and can be bothered I can switch it round and check the face too with this type of holder.

...but I'd argue that in all cases a hybrid is nothing more than a recombination of a previously split line.

Just because offspring are viable though isn't the be-all. Sometimes one of the sexes ends up infertile which isn't particularly smart from an evolutionary p.o.v. - see Haldane's rule **LINK**.

Jon

...but it's easy to get lost in theory and forget that behind it all there are individuals choosing, and being chosen as, mates.

...and as we all know, the mate selection problem is a complex one - often driven by mutual attraction, opportunity or otherwise, based upon innate characteristics which loosely approximate to "environmental fitness". In some cases it's also "the best available at the time"

It can even be arranged by human intervention as in the case of domesticated animals which formed part of Darwin's seminal work (esp pigeons).

I'd argue that the offspring, if viable, are really all individuals. Some may be better adapted than their parents to their environment or less so ... but any classification, even if it's based around the potential for inter-breading, is still somewhat arbitrary and a convenience for us.

Jon

Edited By Jon Gibbs on 24/11/2017 14:31:17