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Member postings for John Haine

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

Thread: Further Adventures with the Sieg KX3 & KX1
18/04/2019 17:44:10

I think I will have to take the plunge into F360...

18/04/2019 16:56:28

Thanks Jason. I guess that it could also all have been done in F360?

Thread: Keyway steel
18/04/2019 09:21:49

If you're going to skim it down anyway, just start with ordinary steel bar? Apart from the dimension I don't thing there's anything special about the steel.

Thread: Further Adventures with the Sieg KX3 & KX1
17/04/2019 07:26:42

I'm sure you've said somewhere Jason, but what CAM program do you use please?

Thread: Telescopic bore gauges
17/04/2019 07:24:10

I have one Starret that goes up to about one inch, and a set of Mitutoyo going from about 6 up to 50 (?) mm. The Starret came from a used tool stall on my local market, probably a quid or so, the other set came from a surplus tool stall at an MEX in a very tatty plastic wallet for probably about 15 quid a while back. I find them very useful and pretty accurate one you get the knack. Moral, look for used ones or a set of good quality.

Thread: Boring on a light mill
12/04/2019 13:48:30

The first would be much preferred if you can get it, but the arbor (which is not a leafy glade) may not be easily replaceable. I have a small Arrand boring head and one of the generic 2" jobbies, the Arrand is a joy to use but the big one decidedly hit and miss on getting an accurate feed.

Thread: Black Holes
12/04/2019 11:23:06

Certainly an amazing discovery. Actually it was a clergyman called John Michell who first suggested them in 1784! He just observed that a massy enough star would have an escape velocity faster than light. And it seems that Einstein actually didn't predict black holes himself though other people did using his theory shortly after it was first published - details in that Wikipedia link.

The Event Horizon Telescope has a website which has a load of excellent information on the system and how it works, well worth browsing.

Thread: Would you mesh with this?
12/04/2019 08:57:36

Sam, while your work is of not much practical relevance these days, it is extremely interesting to clock nuts like me. Quite a few years ago I spent many hours trying to analyse "cycloidal" gears by a series of spreadsheets to get a handle on their performance, because as far as I could tell though there were standard profiles there wasn't any data on just how well they worked (or didn't). I was looking at how well simple circular profiles might work, which are easy to make. Also, all clock gears are made with symmetrical profiles but only one side of each tooth ever engages, at least in the power train. I could see that an article on your results would be very appropriate in Horological Journal or Horological Science News.

Thread: Free 2D drawing programs
12/04/2019 08:49:10

Ian, unless you want to export your drawings to CAM then a free, reliable, and easy to use package is Open Office, which gives you "Draw" as well as word processing and spreadsheets.

Thread: Would you mesh with this?
11/04/2019 12:47:36

Torque variation will affect any escapement. At the least it will vary the impulse, hence the amplitude and circular deviation. If the escapement isn't giving a central impulse it will also cause varying escapement error.

But this is far from the only problem. One tends to think of a clock train as if smoothly moving, but of course it moves in jerks as released by the escapement. Some research has shown that when the escapement releases, the gears only start moving as the sticktion between the mating gear faces releases, so the drive torque gets rather noisy and "chaotic". Interesting paper on this here.

So clocks like Harrison's and "Clock B" at Greenwich have remontoires driving the escapement wheels to try to isolate them from these torque variations. Even then I've seen results from Clock B that show cyclic variations in rate as the escapement wheel rotates due to small inaccuracies in its manufacture.

Thread: Further Adventures with the Sieg KX3 & KX1
11/04/2019 12:36:00

I tend to be a bit wimpish with feeds and often find myself turning the feed up once a cut has started when it's evident that it's too slow.

Thread: shop vac at B&Q
11/04/2019 12:34:16

I have one badged Stanley Fatmax which is good but BIG. At that price, if the size is OK then go for it.

Thread: Folding Bike design & build
10/04/2019 19:35:27

The way the handlebars fold looks as if inspired by a yoga pose! A very nice design and nicely executed.

Thread: Would you mesh with this?
10/04/2019 15:17:31

Sam, if you mean that the velocity ratio changes through the contact cycle, well, that's what cycloidal gear approximations do I think. As noted in the article in Sparks that Michael linked to, that's why the automotive industry started using cycloidal but very quickly switched to involute when they found them noisy running at speed.

Thread: Further Adventures with the Sieg KX3 & KX1
10/04/2019 15:10:05

Andrew, do you touch off the master tool on the table or the height setter? Presumably the latter if the heights of the other tools are measured using the setter? Is your master tool solid or is the tip isolated?

10/04/2019 10:38:20

Tool height setter made from the scrap box, except for one spring and a neodymium ring magnet. Edge finder used a length of 10mm ground stainless from an old printer, one short length of M5 studding, a blob of araldite, and some scrap brass. I started using dowels etc for setting but the speed, convenience and accuracy of even simple methods was a revelation.

10/04/2019 09:29:40

Ron, one way is to use a tool height setter that automatically sets the height to a known value.

img_0209.jpg

"Here's one I made earlier". This is a simple gadget with a TC button springloaded to be exactly 38.84 mm above the table, that fixes down with a magnet. The button is electrically isolated and connects to the probe input on the controller - when the tool touches the button "Z" is set to 38.84 and the tool retracts to 50 mm. You can also see in the chuck an edge finder that works in a similar way which can set the controller X and Y zero to the work edges, or find the centre of a hole, with high precision. Sorry the photo is on its side.

Thread: Would you mesh with this?
10/04/2019 09:02:42

Aha, found it, thanks for the links Michael.

**LINK**

10/04/2019 08:59:03

In a word, tradition. Actually cycloidal gear teeth are not cycloidal but made up of arc segments because the ideal tooth form is very hard to generate (or was, today one would use CNC). Supposedly cycloidal gears don't have "action before the line of centres" which reduces friction, but this may be a myth. I believe that Sinclair Harding, one of the few makers left of high end mechanical clocks, use involute gears in their products. Somewhere I have a link to an article by a production engineer involved in making millions of fuse mechanisms in WW2 that thoroughly shows that the involute was better for precision timing mechanisms. I'll try to dig it out.

10/04/2019 06:55:59

Sam, please don't keep us in suspense! What direction was the pinion rotating?

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