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Member postings for Howard Lewis

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

Thread: Hydrogen embrittlement in steel?
03/03/2016 16:42:44

Also, why paint it black anyway?

Black is a good radiator of heat, so silver paint would radiate less heat, and so aid the external insulation.

Howard

Thread: MEW/ME Mugs going cheap!
03/03/2016 16:24:48

I thought that this was a new slant on "Ceramics in the Workshop", until Neil said that he would look into it.

Reading the Tea Leaves, yet another skill displayed on the Forum?

A long time ago, I had a mug with glazed greasy handprints on it and a nut and bolt inside, but it was withdrawn from service as unhygenic.

Howard

Edited By Howard Lewis on 03/03/2016 16:27:59

Thread: Hydrogen embrittlement in steel?
02/03/2016 19:59:12

Why not get it galvanised? Greater thickness of zinc, and no electrolytic problems.

Not sure that I'd like to be near any pressure vessel where the steel had any hydrogen embrittlement!

Howard

Thread: Useless light bulbs.
28/02/2016 13:48:18

The linear Q H lamps at church seem to fail fairly frequently, which is awkward as they are so high up. They normally run for more than an hour.

In contrast, the security light outside my garage seems to last fairly well, for several years. Maybe this is because it is only on for short periods, and so does not get so hot.

The 24V 50W Q H worklight on my lathe used to eat bulbs, until I filed two slots on opposite sides of the reflector, to improve ventilation. Since then (asking for trouble!) have had no failures. Just as well as around here, (East Anglia) none of the electrical stockists, trade or retail, seem to stock. Fortunately, when I could, I bought a load for stock.

Maybe the problem is related to: frequency of "switch on", (current surge of cold filament); length of time running; ventilation; or a combination of these factors.

Certainly, normal GLS lamps do not like running cap down, (possibly lacking the ability to dissipate heat into the cap, fitting and wiring?), and are reputed to be designed to run cap down.

All types of Fluorescent lamps are better if left running for long periods; again no doubt, because of the effects of the voltage surge generated by the choke and capacitor to make the tube "strike".

Howard

Thread: Vertex HV6 - Corrected Division Table plus universal dividing spreadsheet
27/02/2016 20:01:34

Apologies to everyone!

Somehow, I managed to incorporate the very error that started this thread, because it has cost me so much time and material, and led to my making up the spreadsheet.

Have checked and E mailed a corrected version of the chart to Neil who will post it as a PDF.

13 divisions SHOULD read "6 turns and 36 holes on a 39 hole plate"

This is correct as I have now cut a good 13T gear, and it went into service yesterday.

Again, abject apologies.

Howard

24/02/2016 22:43:14

The spreadsheet was made up for the Vertex HV6 which has a 90:1 ratio, but presumably, copying the spreadsheet, and substituting another ratio for the "90" in the formula, would produce a set of results for a R T or D H with that particular ratio.

Today, using the figures from the spreadsheet, I have produced a fairly good looking 13T gear, so one calculation seems to be right!

Howard

24/02/2016 07:53:33

Have E mailed my revised chart, as a WORD document, to Neil, in the hope that he can transpose it in to a PDF.

The Print out will be laminated for use in the workshop, and an additional copy kept in the folder with the Vertex manual.

My Spreadsheet for all the calcs, running to four worksheets, (One basic, and then one for each of the three Division Plates) is on EXCEL. Most of the results co-incide with the Vertex chart, but NOT ALL. It looks as if some errors are typos, and others, like the 13 Divisions one, of misreading handwritten figures (30 instead and 36 in this case)

If anyone wants this, it is for a 90:1, but can easily be amended for different ratios, (but check a few results against known "good" results, to be sure), send me a PM with an E mail address, and I'll forward it, (Its only 64Kb).

Unless Neil wants to put it on here?

Howard

23/02/2016 17:39:25

Thanks!

So, despite my misgivings, the Vertex manual does contain some errors, (found others as well) and my spreadsheet looks to be correct! Ah well off to turn up another gear blank to Loctite into place, ready for turning and gearcutting.

One day, I will get this job finished.

Howard

23/02/2016 15:49:02

Trying to cut a 1.5 Mod 13T gear, and produced two scrappers.

Thought that it was my miscounting the number of holes, but the second attempt still resulted in the final tooth being much thicker than the others. So it looked as if the increment was a little too small.

Spent some hours setting up a spreadsheet to check the Number of Turns and No. of Holes for the three Division Plates and the various Divisions.

According my calculations, the movement should be given by 6 turns and 36 holes on a 39 hole Plate, not the 6 Turns and 30 Holes shown in the manual. The slightly greater increment would be likely to make the final tooth thinner, and it is possible that the compiler read a 6 as a Zero.

There appear to be other errors, possibly merely typos. Has anyone else had similar problems?

Howard

Thread: My rest with brass knobs on !
17/02/2016 14:10:35

Wish that I could make something as good as that!

Howard

Thread: Wet Belt
16/02/2016 16:52:03

Ford have had a policy of more than one supplier, for many years, to ensure continuity of supply.

At C A V in the 60s we were developing Fuel Injection Equipment that we knew would only go into production if Simms failed to deliver for some reason.

The life of the toothed belt used on the Perkins Prima diesel was never really known. We never managed to fail one in development; so arbitarily set the change period at 70,000 miles when other cars were setting periods of less than half that.

I did the pre production validation testing. This was the same as for the larger industrial engines, and there were no problems. Taxis were covering nearly 300, 000 miles with only routine servicing.

Sadly the emissions stasi in Brussels killed off an reliable and economical engine.

Toyota use a "silent" chain ( to a long proven propriety design) in their engines, and it lives up to its name. And, the marque has a good reputation for reliability.

The Japanese respect quality, and take a longer term view than European or North American manufacturers.

The irony is that the Japanese Quality Systems are those first promoted by an American, Deeming.

Howard

Thread: Sir John to the Rescue
15/02/2016 12:03:08

I made myself a square, and a hexagonal block for both ER25 and ER 32, only to find later, that John had made a more refined and better looking version. Very useful!

Before anyone asks "Why square ones? You can, mill round all sides when its vertical in the vice"

Stating the painfully obvious, lying horizontal, one or more flats can be milled on long material, and it can be held closer to the cut.

Howard

Thread: Bending steel
15/02/2016 01:59:14

Seeing the required end product, my thought was Bending Rolls.

If you want another project, why not make some? The G H Thomas book (Model Engineering Techniques - from memory) has text and drawings in Chapter 18 for a 10 "wide set. I've just finished making a 12" set based on this geared design. If SWMBO complains about the leadtime for her lights, explain that you are making the tools to do the job. Hopefully, she will realise that it is not a "can you just" job.

Howard

Thread: tailstock tapping jig
15/02/2016 01:41:19

I have a Tailstock die holder, so made a tap holder, to use ER collets, to slide on the same arbor. Like the Die Holder, a stud is screwed into the body, to rest against the fourway toolpost, as an anti rotation device.

The slight clearance between Holder and Arbor allows a bit of float to allow alignment.

The grip of the ER collet, even when tightened hard, will still allow the tap to slip if it jams, or bottoms in the hole.

Tempting fate, so far have had no broken taps, even with 3/16 x 40, which was the reason for making it. 40tpi taps will not pull a Tailstock along a lathe bed, (certainly not mine) preferring to strip the thread.

Howard

Thread: RF-25 Belt-sizes and Table Stop Info Please
15/02/2016 01:24:58

Hopefully, you won't have this problem, but my Warco RF25 shredded its primary belt within 6 months from new.

When fitting the replacement, (bought from a local belt/bearing factor) I aligned the motor pulley with the intermediate pulley. (it was out!) This entailed shifting the motor on its mounting plate. About 14 years on, the original secondary, and my early life replacement, belts are still going strong, and look to be in pretty good condition.

Howard

Thread: A question of Mandrels..
15/02/2016 01:14:18

If you have the work on a mandrel, remember that heavy cuts may deflect the mandrel , or cause slippage, as you have already found.

2mm sounds like a roughing cut to me. Better to spend time taking more smaller cuts, than to risk damaging work by trying to rush.

This isn't piecework is it?

Howard

Thread: Making Threaded Studs
15/02/2016 01:01:57

The devices into which a threaded component is screwed, and locked with a screw, are known as stud boxes in my world. They are easily made from hexagon bar, and the locking screw can be of any type that suits, (hex head, Capscrew or grubscrew. The lockscrew ensures that there is enough friction to stop the workpiece rotating whilst the thread is being cut on the other end.

If made of hexagon bar, rather than round, they can be used to set, or to extract studs. To set a stud, drive using the setscrew. To remove a stud, rotate using the spanner on the hexagon bar, but keep the locking setscrew tight with a second spanner. Once finished just slacken the locking setscrew, and the studbox should unscrew by hand.

If using a hexagon head setscrew it is preferable to use hexagon bar of a different size from that of the setscrew head; unless you have lots of spanners of each size.

Howard

Thread: Die defeated by mild steel
15/02/2016 00:49:07

Funnily enough, a few days ago, I did try to cut a M10 thread with a die. The workpiece was JUST under 10mm. With the die adjusted to a good quality M10 bolt, it caused the belts to slip. Then the job slipped in the chuck jaws. Eventually, I got enough threads cut to remove the job from the lathe, hold it in the vice and use a fairly large die holder. The thread was cut by slightly opening the split die, and backing off every quarter turn, to break the rather large curls of swarf. Once "roughed out", the die was reset and cleaned up by hand. As a lubricant, I used bacon fat, (too idle/tight to open the tin of Rocol STD) The nut, of the same quality as the bolt, was an easy fit, which made it ideal for the intended use.

Howard.

Thread: Dial Indicators
15/02/2016 00:34:55

Since a thread on Dial Test Indicators has become one of semantics, remember the story of the foreign gentleman who fell off a cross channel ferry.

As he floundered in the cold water, he cried "I will drown. No one shall save me".

So the crew took him at his word; and he did!

Howard

Thread: BH600G Fine Feed Help
15/02/2016 00:21:37

My memory failed! For anyone contemplating halving the feed rate.

The backgears are 1.25 Mod. (Looked at the cutter and its the only Mod cutter that I have, so for once, must have got it right)

Howard

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