By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for Nicholas Farr

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

Thread: diameter calculation
13/10/2019 22:35:07

Hi Neil, thanks for your comment. The drawing is a bit rough and ready, but the 41 degree angle and the three points were set quite accurately and I think it shows what might seem to be an obscure triangle.

Regards Nick.

Thread: An interesting repair to an Hour Wheel
13/10/2019 18:36:19

Hi, similar techniques were often used on breakdowns during my maintenance years, when production was imperative, although they were repaired or replace during a suitable ASAP shutdown period. If it works and cosmetic appearance is not an issue, then I think it's fine.

Regards Nick.

Thread: diameter calculation
13/10/2019 18:14:19

Hi Gary, a better way of proving the Sine rule works for the example 26 diagram is shown below. This is a half size one but the relationship between the angle and the length of the two sides shown are the same. This shows the integrity of the 41 degree angle and the lengths of the original sides and should help show those who don't quite understand how it works. The extended line B-A becomes the diameter of the PCD for A, B and C and a new PCD drawn on the centre of this line will show the Right Angle Triangle with the red line at a right angle to line B and C and it will be noticed that the new PCD will pick up both ends of the red line and point B.

Excuse the makeshift real world drawing, all the dimensions are close to those actually calculated.


Regards Nick.

Edited By Nicholas Farr on 13/10/2019 18:18:25

13/10/2019 09:07:32

Hi, yes, the question was answered to the OP's satisfaction, If one finds that the evolved thread becomes of no more interest to them, then they are not forced to read it any further, but of course it still interests others.

Regards Nick.

Thread: Help with a boxford c
13/10/2019 08:11:34

Hi Ian, most Boxford lathes were supplied with 3 phase motors, if your motor is a single phase 0.5 HP it may not be powerful enough for some operations. Tony on the Lathes website suggests that at least a 1 HP should used for single phase, which is what I have on mine and I have not had any issues with the lathe being underpowered or the motor getting overheated when being used all day.

Regards Nick.

Edited By Nicholas Farr on 13/10/2019 08:14:08

Thread: Free software and human nature
13/10/2019 07:29:16

Hi Clivel, it happens on this forum often, someone asks a question and gets a bundle of advice from various people and! not even so much as a "Ta" for the effort for the help.

Regards Nick.

Thread: What is this called?
12/10/2019 11:14:12

Hi, have at look at Window Furniture

Regards Nick.

Thread: diameter calculation
12/10/2019 09:12:34
Posted by Howard Lewis on 11/10/2019 16:14:05:

Being simple, I drew a circle with three chords 65 mm long. Then a 30/60/90 degree triangle, with one side being half the chord = 32.5 and used Sine or Cosine to calculate the Hypotenuse. Then doubled the answer to get the diameter, which my calculator said was 75.055535, if you want be frightfully accurate. Me? I'd settle for 75 as being about as good as i could get, although I might set the machine to 75.06 mm or 2.955 inches in old money.

That is about as complicated as my puny brain can tolerate.


Hi Howard, actually you don't need to half to cord, as you can use 65 divided by Sine 60 or Cosine 30 to give you the diameter directly. My original drawing shows using half a cord to get the radius directly, which is what someone asked for a while ago and of course Sine 60 would have given to same result.

Regards Nick.

11/10/2019 13:43:53

Hi S.O.D., I guess I should have filled you in with the proceeding piece of text to example 26 above, which is;


Of course you need to understand the Sine rule, which I'm a bit rusty on now having not used it for a long time. Apologies if I've confused you and others of course. This rule though, would have solved Paul's question also, but the other diagram was already in my album.

Regards Nick.

11/10/2019 10:05:06

Hi S.O.D., I've found this in one of my books, but it does give a couple of dimensions and an angle, but you've asking about random placed points and I suspected it would involve Algebra as Andrew has said. However I could never get to grips with Algebra, which seems that MichealG's search is full of.


Regards Nick.

11/10/2019 08:31:12

Hi NDIY, the OP asked the diameter for 65mm without stating a tolerance of any kind. The mathematical answer is exacting within the practicalities of calculation and from that the OP can fashion his own tolerance and I'm sure he should be able to get it very close to his needs.

Regards Nick

10/10/2019 23:41:40

Hi Mike, have you been using my calculator?

Regards Nick.

10/10/2019 21:21:12

Hi Paul, a little bit of Trigonometry will give you the answer, just substitute the 100 shown on the diagram below with 65.

trig solution0001.jpg

Regards Nick.

Edited By Nicholas Farr on 10/10/2019 21:21:47

Thread: Help with a boxford c
09/10/2019 20:54:52

Hi, there seems to be two versions of securing the intermediate pulley shaft, for the underdrive lathes, the older one being with bearings on a pair of hangers and the later one which is fixed into the sides of the cabinet. Mine is the later version and the intermediate pullies rotate with bearings on the shaft and this shaft has no adjustment of any sort.

2019-10-09 12.04.37.jpg

I assume the hangers on the older version have slots in them for the bearing bolts, however I guess these slots are not very long and are provided for initial adjustment at the factory build, as according to the "Know Your Lathe" manual, the instructions for tensioning the link belt is to remove links as necessary.


Regards Nick.

Edited By Nicholas Farr on 09/10/2019 20:56:16

Thread: I am a metal sculptor and happy to be here!
08/10/2019 06:35:35

Hi Patrice, very nice work, I like them.

Regards Nick.

Thread: Grinding wheel 'washers'
07/10/2019 23:09:55

Hi Bill, or just get some Blotting Paper

Regards Nick.

P.S. there are others available, the link is just an example.

Edited By Nicholas Farr on 07/10/2019 23:13:45

Thread: Help with a boxford c
07/10/2019 23:03:31

Hi Ian, Brammer Link belt is usually fitted to Boxford lathes Brammer Type much quicker and easier than having to remove the headstock spindle. This type of belt is widely used on industrial machines. My underdrive Boxford has this type and I've only had to remove about three links in the last 15 or so years, to take up slack as the belt wears as there is no tensioning adjustment for this belt on the underdrive models. Of course you can get the modern type of Power Twist if you don't like the pins.

Regards Nick.

Thread: Resistance Soldering question
06/10/2019 08:37:40

Hi Patrice, I'm not familiar with resistance soldering or its techniques, but like Kiwi Bloke has said, maybe pre-heating could be an answer. If using a flame directly is not desirable, then maybe a hot plate of some description might in order, which could be heated in a few different ways. One way I used a hot plate instead of a soldering iron or a direct flame, is shown below where I soldered a thin piece of brass shim to a thicker brass ring and then turning it over to solder another one on the other side.

hot plate soldering.jpg

The heat source is a cheap camping stove type attachment for a gas blow lamp cylinder and the block on top is just to hold it down. Hope it can help or give you inspiration for some other technique.

Regards Nick.

Edited By Nicholas Farr on 06/10/2019 08:40:58

Thread: Good practice for lathe circuit design
04/10/2019 15:02:04

Hi Rainbows, as far as your E-stop goes, it should stop anything that can automatically start again after a power cut or when the E-stop is released, i.e. anything that moves, things like DRO's should be OK unless a sudden return of power would cause a surge into any electronics etc. and do them damage.

Regards Nick.

P.S. More or less what David has said.

Edited By Nicholas Farr on 04/10/2019 15:04:23

Thread: Metal expansion
04/10/2019 14:42:36

Hi, if you think about it, being that most things expand equally in all directions, unless otherwise restrained, think of the metal bar in a vice being heated up and then just drops out when it cools without opening the vice, then take the amount that the metal would expand towards the hole compared to the circumference of the hole, then it stands to reason that the inside of the hole will expand a greater distance and will have to become bigger. Of course, this is assuming that the whole piece is heated uniformly, because if it was only heated around the hole, it would be restrained by the cold metal surrounding it and the expansion would be greater sideways and the hole may even stay more or less the same size.

As for water does it really expand when it freezes? water becomes ice when it freezes, so maybe it can be considered no longer water. Ice of course is less dense because it expands and is lighter than water for the same volume, hence it floats on water.devil Change of state and all that.

Regards Nick.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Meridienne oct 2019
Eccentric July 5 2018
TRANSWAVE Converters
Eccentric Engineering
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest