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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: Cast Iron For Boxford Change Gears?
22/05/2019 09:00:22
Posted by DC31k on 21/05/2019 20:41:17:
Posted by Brian Wood on 21/05/2019 18:06:08:

Doing the maths, 135/127 = 1.06299 where 68/64 = 1.0625. There isn't another choice available either I'm afraid

 

There are in fact three other choices available that give better approximations than 17/16 (or its multiples). 84/79, 101/95 and 118/111.

While none of these are common gears, to say that nothing else is available is not correct.

In any discussion of change gears, the many continued fraction calculators available online for free are an invaluable resource.

You are of course quite right, I was being a bit economical with the truth, but in my defense I would suggest that for most joining threads or short couplings of say 25 mm in length, the 17/16 approximation and it's multiples, will make quite adequate joints with tolerable errors, and from wheels of sensible sizes.

The alternative combinations all include awkward primes and the last at 118/111 is perhaps a lot of work to make, you might just as well go the whole hog at that stage for 135/127

I'm sorry to have misled people

Regards Brian

 

Edited By Brian Wood on 22/05/2019 09:01:14

21/05/2019 18:06:08

Hello William,

Nigel Bennett suggest a combination 64/54 delrin gear as a translation gear. The material will I'm sure do well for your needs, BUT be careful over specifying the tooth count if you are following up on his link

Boxford 280 lathes come with either 6 mm or 4 tpi pitch leadscrews, yours might be 3 mm as would seem to be the case with a 135/127 translation gear and a better fit to your needs would be with 68/64 for a leadscrew of that pitch.

There is an error over the pukka conversion which amounts to 0.05 mm in 100 mm of thread, per turn of the leadscrew.

Doing the maths, 135/127 = 1.06299 where 68/64 = 1.0625. There isn't another choice available either I'm afraid

Regards

Brian

 

Edited By Brian Wood on 21/05/2019 18:07:20

Thread: Grizzly Beers
19/05/2019 10:25:25

How many 'hats' can you wear Neil ? !!

I can't be there unfortunately, but I hope the event goes well and makes lots of dosh for a good cause

Best wishes

Brian

Thread: Harrison's Equipment
18/05/2019 11:11:40

Haggerleases,

Nostell Priory, a little north of Wakefield in North Yorkshire. has a running Harrison clock that is on show to the visitors to the building. It is a National Trust establishment and this is the only one of his wooden long case clocks kept running now. There are two other examples, one at the Science Museum, the second is at the Worshipful Company of Clockmakers in Guildhall London, This one, the youngest, by about four years, was made in 1717.

In 2008 I made a nylon and aluminium winding key for it to spare NT the use of the only remaining copy of the wooden one they were using at the time, itself a beautifully made copy in boxwood of the original. I never got a word of thanks or even an acknowledgement that it had arrived safely in the post, along with spare parts, which I now understand were separated from it and promptly lost! I do though understand that my key is used.

Engineering in Miniature published an article of mine on the construction of that key in their issue of April 2013

I believe winding days are on Wednesdays at 11 am, it is something of a ritual

Regards

Brian

18/05/2019 09:46:25

I understand that Harrison is also credited with making caged ball bearings for his sea-going chronometers, all in the interests of reducing frictional losses as much as possible.

The man was well ahead of his time

Brian

Thread: aching ribs - posture
16/05/2019 18:49:26

Hello Mick,

I don't know how tall you are, but would putting the lathe onto raising blocks give you a more upright posture in use?

Regards

Brian

Thread: Bandsaw blade jig
12/05/2019 13:35:34

I agree with you Phil, very neat indeed.

Brian

Thread: Myford ML7 - Size of Mandrel Through Drilling?
11/05/2019 18:33:07

mgnbuk,

My apologies Nigel; mine is clearly a much younger model. Sorry to doubt you, especially as you found an ingenious solution to read it.

Regards

Brian

11/05/2019 13:32:15

mgnbuk,

How can you miss it Nigel? It's on the front shear vertical face, right beside the gap and in the easiest position imaginable.

Brian

10/05/2019 17:22:18

0,630 inches (16 mm) on serial number KR 151488. Mine is the ML7R which has the S7 headstock and spindle

Brian

Edited By Brian Wood on 10/05/2019 17:23:27

Thread: Steel boiler storage.
10/05/2019 12:59:56

Brian,

I think the best choice of those you list is to store if full with treated water, making sure you don't leave air pockets. I recall this is the approach used at the Crofton Beam engine pumping station on the Kennet and Avon canal near Malborough.

They have a spare boiler stored outside; I don't remember if they use treated water for that storage but they would need anti-freeze which strongly suggests a corrosion inhibitor is included in the mix

Regards

Brian

Thread: Sump Plug
07/05/2019 17:47:36

I might be tempted to make a square headed socket a short distance away from the end in a piece of 30 mm flat strip having some thickness about it and keep that in the toolbox for when it is needed next time.

A snug fit on the square head of the plug and a thump on the far end with a hammer should shift it with ease in the future.

Regards

Brian

Thread: Chester DB10 thread cutting ???
03/05/2019 10:01:31

Hello Ian,

That looks like a nice piece of work, thank you for showing us what the collective prodding of grey matter helped you produce as a result.

Regards

Brian

Thread: Sump Plug
01/05/2019 16:49:54

Ian

I have in the past in a similar case gripped the square in the jaws of a small vice with a short bar for leverage and used that combination to work it out of the sump.

Try a touch of tightening first to break the grip of the thread and then quickly follow up with the normal unscrewing. Soaking the thread joint with easing oil is a good prerequisite

I hope that helps

Brian

Thread: From the ground up!
29/04/2019 08:36:02

Hello John,

I agree with the analysis from both Nick and Graham but would add that I don't think the catch plate would fit your lathe spindle, the central threaded hole looks too large.

Regards

Brian

Thread: Brazing steel
28/04/2019 18:52:13

Hello David,

Brazing will be perfectly OK on that component, it is likely to need more post joint cleaning to remove the scale. Try painting the other surfaces with Tippex before heating to reduce the scaling

Silver solder would be kinder in that respect,

Regards

Brian

28/04/2019 12:46:08

Hello David,

I have used Sifbronze to make joints and repairs to all manner of steel parts, it really isn't fussy in that respect. You might also like to know it works well on cast iron.

For that case do go to the trouble of careful slow cooling to help any locked in stress to dissipate and use a big propane flame to heat up the parts you want to join before going in with oxy-acetylene for the brazing itself.

In some cases of castings, I use the propane torch to slow down the cooling

So, have a go.

Brian

Thread: Does anyone know where I can source a Myford 34t change gear?
28/04/2019 11:08:45

Hello Rod,

At the risk of sounding rather stuffy, the "cheat" gears as you put it do save a lot of time and leave the fine feed arrangement that is so prized still available, a facility that is lost by mounting up the pukka Myford metric gearing conversion set.

I don't really see what is so dreadful about having an simpler and much cheaper alternative, I'm sure there is room for all in the sales area of these additional components in one form or another. The results in either case are still approximations, some are very close to being mathematically correct and quite good enough for all but the most demanding needs

Brian.

Thread: From the ground up!
27/04/2019 18:52:01

Hello John,

From memory, the gear cover at the headstock end with the two humps in it is very similar to pictures of Mickey Mouse, so I think your's is correct for ML4. The change wheel cover also looks familiar, but the last time I saw mine was >30 years ago, so don't quote me

Thank you for the lavish praise you have directed my way but I think it should really be aimed at other contributors, they have really taken on the baton holder's role now and with my recollections based on such a long time ago, they will be far more likely to give you reliable advice over the mounting of change wheels for instance.

I know you plan to sell the lathe on, but I have a comprehensive gearing pdf for 8 tpi non gearbox lathes that will include yours for a £2.50 contribution to the REMAP charity, a worthy cause that aims at making life a bit easier with bespoke gadgets for those unfortunate individuals who are handicapped in some way.

If you would like a copy, send me a PM with your email address.

Regards

Brian

25/04/2019 18:16:32

Hello John,

It would help us a lot if you tell us all what gears you have with the lathe, then one of us can suggest an arrangement to give a feed of some sort to the leadscrew.

As it seems you will be selling the lathe on anyway, that will be enough to test it out

Brian

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