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Member postings for Jon Gibbs

Here is a list of all the postings Jon Gibbs has made in our forums. Click on a thread name to jump to the thread.

Thread: Boring Bar Holder
14/03/2016 17:24:48
Posted by JasonB on 14/03/2016 15:31:20:

I kind of wonder if its worth making a "heavy duty" holder and then putting a spindly 3/8" bar in it, even the larger 5/8" one is not exactly heavy unless the standard Myford topslide and toolpost is that flexible? Or am I missing something?

Probably not but all things are relative

I think the limiting factor in this setup on the diameter of boring bar is the hole through the "plug" which is 3/4" in the drawing but even a 5/8" boring bar on the old ML7 would be tricky thing to hold otherwise.

Jon

Thread: Edge Finder
11/03/2016 13:52:06

Hi Bob,

I have just bought a second hand mill and I also bought HH's book too.

I followed the first few chapters and have made my own tee nuts etc because the stud size of the standard tee-nuts for my 14mm tee-slots is M12 which seems overkill and I'd rather use M10. I also made my own parallels using HH's instructions.

I haven't made the dividing head or the boring head but I might give the latest boring head in MEW a try because many of the techniques from HH's methods could get used I hope and I already have the stock for a round version. I also have a rotary table already so have less need of a dividing head.

I think that where I agree with you is that these two projects look quite daunting at first sight but I'd suggest that in reality, when broken down into their individual operations I don't think they are as big a jump up as you are suggesting.

HTH

Jon

Thread: What Did You Do Today (2016)
11/03/2016 09:39:50

I finally finished off my take on HH's simple end-mill sharpening jig for the bench grinder.

Instead of the square section blocks with holes and set-screws I decided to base it around a home made ER32 block, with a respectful nod to Sir J.S. of Bridgeport, and am pretty chuffed with the results.

I just bought a second hand mill with what turned out to be a load of blunt end-mills and slot-drills so I can see it'll get a fair bit of use.

It's no good for the edges of course but for the ends it seems to do the job very nicely - had to give a freshly sharpened end-mill a go last night and it cut very sweetly.

Jon

Thread: holding small screws
10/03/2016 11:35:46
Posted by Neil Wyatt on 10/03/2016 11:13:53:

This one is in the USA so postage is more than the cost but it should get you started on google...

**LINK**

Neil

RS do the same screwdriver by the looks of it...

**LINK**

Jon

Thread: Brain Teaser
04/03/2016 16:07:24
Posted by Jon Gibbs on 04/03/2016 16:03:08:
Posted by Trevorh on 04/03/2016 15:29:51:

Tube is measured by OD Pipe is measured by ID

+1

and, confusingly, domestic plumbing copper "pipe" is actually tubing since the OD's of 15mm, 22mm and 28mm are the outside dimensions. In the old days 1/2" and 3/4" copper pipe was pipe.

Jon

04/03/2016 16:03:08
Posted by Trevorh on 04/03/2016 15:29:51:

Tube is measured by OD Pipe is measured by ID

i hope

+1

Jon

Thread: Bronze Wool?
04/03/2016 10:21:45

Thank you all very much for the information and special thanks to Julian for your very kind offer.

I'd seen the amazon listing but wasn't convinced that the prices were realistic - but the Brownell's site which I'll bookmark for the future seems to support these prices as reasonable.

I'll get back to my friend with this information.

Jon

03/03/2016 20:07:25

Hi All,

One of my woodturning mates was asking me whether I knew any suppliers of bronze wool which he was told was an engineering abrasive?

He wants a non-rusting alternative to steel wool for finishing but I had to admit that I'd have never seen it or heard of it.

Any advice or tips please.

Many thanks

Jon

Thread: Babbit = Pewter ?
25/02/2016 22:25:15

Some interesting information here...

**LINK**

[I'm not sure I'd be drinking the tea after it'd had molten Cadmium alloy teaspoon in it]

...but, it might be better to create two intermediate alloys first - one a 50:50 mix of tin and copper by adding tin to molten copper and a second one a 50:50 mix of tin and antimony by adding tin to molten antimony.

Then, add these in the proportion 1:1 to 3 more parts of molten tin.

Jon

 

Edited By Jon Gibbs on 25/02/2016 22:28:21

25/02/2016 18:16:50
Posted by Tim Stevens on 25/02/2016 17:19:59:

Not quite that simple - you need to make sure that the various metals all dissolve together, with no 'filings' or other bits left undissolved. This can take time at temperature, and meanwhile oxidation is producing scum or dross, which removes some of the metal (but not in proportion) from the mix.

It can be done, but if it were simple there would be no point in the various off-the-shelf suppliers (who have all gone down the plug-hole of fate, muttering 'bloody lead indium' as they went).

Cheers, Tim

Your point's well made because of the high melting point of the copper (almost 1100 degrees C) and the difference from antimony at 630 and tin at only 230.

...but my guess is that the most deterioration will be to the tin and antimony. So, if you heat a generous amount of tin and antimony with the minimum amount of copper you may get close to a usable alloy for a one-off. All of the metals are fairly stable. But then the mixture needs to get to and stay above 1100 degrees for long enough to melt the copper and get it to mix. The 3 metals all have very similar density 6-8 g/cm^3 and so convection currents in the melt are likely to do the mixing ok with a quick stir.

I think it'd be worth a go for a one-off.

Jon

Edited By Jon Gibbs on 25/02/2016 18:17:42

25/02/2016 01:06:32

In that case, mix your own alloy (by weight I assume)

Simples

Jon

25/02/2016 00:51:05

Some old pewter has lead which may not be what you want and from what I've seen pewter doesn't have as much Cu or Antimony (Sb) as true babbitt...

**LINK**

**LINK**

A good source of pure tin is lead free solder and so you could try your own Sn/Cu mix by melting some tin and chucking in enough copper filings? Antimony is a bit more tricky.

HTH

Jon

Thread: couriers
23/02/2016 20:30:57

Have you tried these folks...

**LINK**

They're not quick but the price is often reasonable and you can get an online quote.

HTH

Jon

Thread: end mill holder
16/02/2016 15:17:13

+1 for ER collets.

You could also make your own ER32 (or ER40 which has same collet internal angle of 8 degrees but larger thread & nut) collet chuck to fit your headstock thread. This will be a cheaper alternative than an MT3 chuck and would also give you another workholding method for stock up to 20mm diameter since you can pass it through the headstock bore without obstruction.

If you make the body then all you need are the collets, nut and spanner.

I can vouch for Harold Hall's instructions here... **LINK**

HH also gives instructions for the closing nut but at around £7 each for a bearing version which is superior then I'm not sure it's justified.

HTH

Jon

Thread: Wood Treatment
16/02/2016 09:58:07
Posted by Michael Walters on 16/02/2016 09:26:20:

and they banned it just because a few people wanted to spray it out of a gun, virtually any paint is harmful to inhale.

Edited By Michael Walters on 16/02/2016 09:28:37

No, they banned it because it is a pretty nasty carcinogen and can be imbibed even through touch. It is harmful to the environment especially if it enters the water table and since it never really dries completely the effect lasts long after application - a particular problem with telegraph poles and fence posts. The funny thing is it's still used for telegraph poles though I think basically because it's the best preservative and big business can ignore such bans in practice.

I agree that nothing's quite as good as creosote for preserving wood but timber is actually cheap enough and is sustainable after all.

Jon

16/02/2016 09:35:19

Sorry but I've heard enough about elm

Elm's a traditional material for coffins and pipes because they stay wet. They even found Roman elm pipes in York during archaeology digs. Under those conditions it will not rot

...but these pads are above ground and will be alternately wet and then dry. Under those conditions elm is no more durable than anything else. Added to that, it is actually quite soft and so would wear away in this application in no time IMHO.

Where elm also gets used is in the hubs of cartwheels and anywhere else where split resistance is a prized property but I can't see that being useful in this application.

For modelling purposes it'd be hopeless too IMHO because the figure is too bold and big.

I agree that the contact with cast/wrought iron would create black staining in oak but that tends to be pretty localized IMHO depending how old the pads are supposed to be on the vehicle.

HTH

Jon

Thread: ML7 lathe
15/02/2016 19:02:33

Reverse is handy even on an ML7 sometimes, such as when cutting metric threads on an imperial machine or vice versa.

In this case you want to reverse the lathe to return the tool to the start of the cut without disengaging the half-nuts. Under those circumstances there's no reason for the chuck to unscrew.

HTH

Jon

Thread: Wood Treatment
15/02/2016 16:29:01

Oak and chestnut heartwoods are almost identical in appearance (save the oak medullary rays) and tannin content leading to similar durability although chestnut shrinks and expands slightly less.

...but oak has superior properties in terms of strength, flexibility etc and is heavier. So, I'd be very surprised if these shoes weren't made of oak heartwood. Sapwood rots very easily and quickly.

I'd also be surprised if there'd be much benefit in additional preservative as it would wear off quickly at least on the underside.

Seasoned oak heartwood will last for years untreated provided it's either always wet or always dry, it's the repeated wet/dry cycle that leads to deterioration. The problem with preservative coatings like paint/tar etc is that they can often let in and then hold moisture that would otherwise run off and dry quickly and that can encourage rot.

I'd stick to the natural maple or lightly colour with perhaps a light oak stain. although the end grain will tend to go "over" unless you're careful.

HTH

Jon

Edited By Jon Gibbs on 15/02/2016 16:33:45

Edited By Jon Gibbs on 15/02/2016 16:42:55

Thread: ML7 lathe
15/02/2016 14:22:37

You can download an ML7 manual here

**LINK**

although you may have to register for the "myfordlathes" Yahoo Group first but that is free.

FWIW I installed a DOL starter between the mains inlet and the Dewhurst switch to save the contacts from being switched under load thus hopefully prolonging their life.

HTH

Jon

Thread: RF-25 Belt-sizes and Table Stop Info Please
15/02/2016 11:19:37

Vic,

Thanks

I must admit that one motive for making, over buying, was that the commercial clamp sets for the T-nut size I have on the table (i.e 14mm) take M12 studding which seems a bit OTT to me and also meant that the M10 studding I inherited with the mill was scrap. So my bits are all sized for M10.

Jon

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