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Member postings for Brian Wood

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

Thread: New Myford Owner
18/11/2019 12:42:29

Hello Darren,

Welcome to the Forum, you will have plenty to do by the sound of it

Regards Brian

Thread: Mitutoyo DRO Fault
16/11/2019 18:04:09

Brian,

I am a bit confused in my interpretation of your testing analysis. I am just a simple soul really!

If you take the X channel for example, does that give a different reading [as it should] when the X position is changed? And then, with the X input transferred to Y channel, do you still get another series of results that change as one expects? If so, the scale and reader are both good as well as the display.

Taking the same two tests but now using the Y channel instead. if the scale or reader are faulty then the same fault condition will be seen on either test.

I think you will be able to establish by these means whether a scale or reader are at fault and which one or whether the fault lies in one of the amplifiers in the readout

Spare ;parts like scale and/or readers may still be available from Mitutoyo. The display module too perhaps, but that is likely to be expensive.

Regards Brian

Thread: How do I undo these leadscrew nuts?
15/11/2019 15:50:40

C--C-- Baloo,

No, not really. It is more a case of feeling the degree of resistance to motion that exists in the bearing when the nuts are clamping it, especially the thrust bearing, and reproducing that later when you reset them. Doing that by counting or marking won't be sensitive enough

Too much pressure on a thrust bearing can in time indent the race and the bearing begins to feel 'digital' I can't think of a better description. For that to take place it would have set been so tight as to be stiff to move and clearly unhappy Too far the other way and it is then too slack to take up end play. The happy medium is to achieve no detectable end play along with free rotation of the bearing.

It is all a question of judgement which was why I suggested you felt it's rotation characteristics by hand before you disturb the setting of the two nuts and return to that condition after you have done whatever you are doing.

I hope that helps.

Regards Brian

Thread: What is this Tom Senior colour?
15/11/2019 11:40:24

And me again in reply!

An off white would be just fine---I have no idea what the "official" colour is but that would look OK.

Regards Brian

Thread: How do I undo these leadscrew nuts?
15/11/2019 11:35:41

Yes, they are double nuts, one locks the other and they are used to set the pre-load on the bearing

You can release them with spanners shaped like hook wrenches, but with pins to fit the holes rather than squared off hooks. They are not difficult to make really. Test the pre-load on the bearing, one of which is a thrust bearing, before you release them so that you have a feel for how they were set beforehand.

Before I made such spanners, and you will be surprised at how often they are used on machinery, all in different sizes of course, I used a pair of water pump pliers when I had to move mine in a hurry. Being slim they are about the right size.

Regards Brian

Thread: Boxford metric lead screw fitted to imperial lathe?
11/11/2019 14:51:54

Hello again Cupboard,

How satisfactory to hear at last the full story. I don't think it would have been possible for anyone here to guess at the way the drive was coupled to the leadscrew; no wonder the results were odd and confusing. Thank you for completing the saga

I am reminded of one query we in the forum were able to solve 'remotely'. for a posting some time ago. It all boiled down to him using a change wheel of 54 teeth that had been incorrectly stamped as 45 teeth and only by suggesting he actually counted everything was the truth of that situation found

Regards

Brian

Thread: What would you call this tool
11/11/2019 14:38:22

Possibly a positioning aid for precision welding

Brian

Thread: Workshop series
10/11/2019 18:32:16

I endorse the series too, lots of good information

Brian

Thread: Cutting an unlisted thread on colchester student
07/11/2019 08:29:45

Hello Ian,

Thank you for bringing us up to date with the outcome of your experience. It is always gratifying to hear that suggestions have worked, as planned, and that you are pleased with the outcome.

Happy threading

Regards Brian

Thread: Cutting stainless steel rod. Bandsaw or chopsaw?
04/11/2019 14:41:48

IanT

I don't know what tooth count you are considering but my experience has been that 10 tpi is a good general purpose choice for hacking though stainless steel bar, cast iron to 4 inch diameter, the cuttings literally pour out of that and other materials.

Not good on thin walled tube though, it hates it and for that I use 14 tpi as a compromise between getting some pace out of the job and cutting it cleanly. Good on S/S tube as well

Tuffsaws are now selling variable pitch bi-metal blades; my old choice of 10 tpi is now catered for by 8-12 tpi. I haven't actually tried one yet as I'm using the last of my older stock.

I certainly won't be using carbon steel blades again in the future, their life is desperately short on the more demanding materials

Regards Brian

04/11/2019 10:34:36

I did a lot of 30 mm diameter 304 bar cutting recently on my Axminster bandsaw and was getting through good name 10 tpi carbon steel blades in two cuts per blade. I expected rapid failure and was glad of the excuse to clear my stock of four in favour of far better specification bi-metal blades in the same tooth pitch from Tuffsaws. The customer will have the cost of the new stock added to his bill anyway.

The difference in performance is marked with 10 cuts in that diameter on this material already and now I have a number of 12 mm diameter pieces in 304 to cut to go with this job. So far it happily cuts away without wandering or struggling

Noise of an angle grinder probably wouldn't bother most of my neighbours being elderly and hard of hearing, I just didn't fancy the heat induced hardening through which I needed to drill and tap deep holes [M6] at the bottom of 10 mm diameter reamed pockets.

Brian

Thread: Boxford metric lead screw fitted to imperial lathe?
30/10/2019 13:59:03

Interesting as all this has become, it is perhaps easy to overlook the fact that it only came about because of the rogue fitting of a metric leadscrew to the imperial screwcutting gearbox on an imperial lathe, giving rise to the work-arounds that have been proposed to save the owner the expense and hassle of re-equipping the lathe

What might be instructive now would be to see if similar solutions can be found for a case where a metric gearbox has been mated to an imperial leadscrew.

I feel a full bottle of gin might become an important aid in bringing those answers to an eager public!!

Brian

30/10/2019 08:35:06

Bazyle,

What a mine of information, thank you. And all very clever too. With the working laid out as you have done I can follow the logic now, it certainly wasn't obvious to me before.

Most helpful

Brian

29/10/2019 16:57:13

Bazyle,

Now you have confused me completely! I could not follow the logic in your expression for Colchester conversions of 19/13 /29

Please enlighten me over what I feel sure is a typo somewhere.

Regards Brian

29/10/2019 09:36:02

DC31k,

Thank you for your endorsements; as you might have guessed I like the mathematical challenge such opportunities present, particularly if the outcome is to be able to avoid having to re-equip what might be a perfectly satisfactory machine.

I too would recommend Martin Cleeve's splendid book on screwcutting, it is a bible on my bookshelf and is now stuffed with little notes and markers I have put in it over the years

I liked your neat table for the metric arrangements, it was a clever way of presenting the necessary information as a simple ratio and a method I shall remember and use if I may.

Cupboard

You have found me out! That was exactly my thinking which led me on to the adjustment gears of 55 and 52 and they came from the method Martin Cleeve uses to establish gear pairs from a ratio value. As for holding a pair of gears as a compound pair it is basically a second stud, readily available from Boxford as a standard part.

Regards to you both Brian

28/10/2019 18:18:23

Hello again Cupboard,

I have been "playing" again with your dilemma and I think there is even a way round the 3 mm pitch leadscrew [without having to change it] to be able to get imperial pitches as direct reading values as if the lathe was equipped with the standard 8 TPI leadscrew.

What is needed is another set of adjustment gears interposed between the 20 and 56 gears to fool the system into thinking it has the right leadscrew

These are a compound pair, running in place of the 80 T spacer of 55 teeth mated to 52 teeth.

Setting up the chain this time is now 20 driver, 52 driven with the 55 T of the compound gear driving the 56 gear into the gearbox. As before with the metric set up we looked at earlier, the 56 gear will need a spacer so that it can mess with the 55.

Checking the maths for a few standard pitches we get for 8tpi the following

20/52 X 55/56 X 3mm pitch (leadscrew) X 2.8 (gearbox ratio for 8 tpi) gives a pitch of 3.173 mm which is 8.0048 tpi

and for 32 tpi we get

20/52 X 55/56 X 3( as before) X 0.7 (gearbox ratio for 32 tpi) gives a pitch of 0.793 mm which is 32.019 tpi

A third result for 40 tpi is

20/52 X 55/56 X 3 X 0.56 (gearbox ratio for 40 tpi) gives a pitch of 0.635 mm which is 40.024 tpi

I agree these aren't exact values but it is more readily achieved with realistic gear sizes than 120 and 127 which do give exact result. Ask your friend to print a 52 gear, the 55 is I think a standard wheel.

Time for a stiff gin now I think

Brian

 

Edited By Brian Wood on 28/10/2019 18:20:22

27/10/2019 20:28:28

Hello Cupboard,

I don't think you need another stud, but you might need a spacer at the gearbox end.

Taking an example:- A good one might be the 1.75 mm pitch that I spotted as incorrect

Using the correct values, you would set up the whole train, ignoring the reversing cluster gearing, as 20 driver, 40 driven which is also coupled, on the same stud, to a 35 driver[, that in turn drives the 56 input gear to the gearbox.

That gives a pitch of 1.7498 mm [ ie 1.75 mm] with your 3 mm pitch leadscrew. The spacer will be needed to position the 56 T wheel on the gearbox out by one wheel width to couple it to the 35 tooth wheel. If these wheels are too small to make the linkage, as I suspect could be the case, then an idler can be added at any place in the chain to 'fill' the gap. Being an idler, it plays no part in the gearing calculation any more than a belt does linking two pulleys. It will though have the effect of reversing the leadscrew rotation, readily corrected by moving the reversing cluster to the other position.

If you have the gears, the 7/8 ratio could be set up as 70/80 instead, that will bridge any spacing issues

I hope that makes things somewhat clearer

Brian

Edited By Brian Wood on 27/10/2019 20:29:17

Edited By Brian Wood on 27/10/2019 20:31:31

27/10/2019 18:37:09

Cupboard,

You have the right idea, but what DC31k has omitted to say is that the driver on the spindle (after the reversing gears) will be 20T and the gearbox entry spindle needs a 56T gear in all cases.The change gears are fitted in the chain linking those two.

Sadly, and I hate to have to point it out, but there is one error in his table in the listing for 1.75 mm pitch. The change gear ratio should read 7/8, which could be 35/40 as you have interpreted the ratio.

As listed, you will get a pitch of 1.1427 mm. Otherwise, all is well

Kind regards

Brian

Thread: Packed Boring Bars
24/10/2019 10:52:40

ega,

I saw only coolant pouring out of the chuck, not chips. I did also wonder if the timber " cushion" was being shaped by the cut edge of the hole being bored as the bar was powered down into the hole. They were described as sacrificial so I assume new ones, roughly shaped, were fitted for each tube being bored.

Clearly the lathe in use had a long bed; it was rather frustrating not to get a view of the holding arrangement on the saddle end of the boring bar. The process did leave a nice looking finish ready for honing to size.

Thank you Clive for the link, it was interesting and a process I have not seen before

Regards Brian

Thread: Manual machinist, local to the North East required.
15/10/2019 08:49:29

Neil,

I've sent you a PM (personal message) Look for a flashing inbox symbol top left on this page to read it

Regards

Brian

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