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

Member postings for Sam Longley 1

Here is a list of all the postings Sam Longley 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Tolerance for needle bearings?
05/08/2019 08:22:56

deleted

Edited By Sam Longley 1 on 05/08/2019 08:25:59

Thread: RENAULT DAUPHINE
03/08/2019 19:25:17

Back to the IMP- BMW made an equivalent to the Imp about the same time. I seem to recall that it had an odd crankshaft which may have had roller bearing big ends

02/08/2019 13:56:40
Posted by Cornish Jack on 02/08/2019 12:55:45:

Re. the Imp, wasn't one of the major problems the pneumatic throttle operation? Never had one but heard tales of the throttle tube coming adrift. Seem to remember they were much favoured for racing.

rgds

Bill

Yes ! used to watch them at Brands Hatch coming out of Druids , down the hill & round the South Bank with the inside wheel off the ground racing the minis. Finally lost out to the Anglias.

Thread: IC engine tractor conversion query
01/08/2019 07:02:47
Posted by AdrianR on 31/07/2019 13:47:47:

I think the conversion to an electric motor is easy, the hard bit is getting the batteries.

The energy density of batteries is very low compared to fuel and to have a decent run time you need huge batteries. Which if are lead acid are also very heavy.

Your 12HP engine would need to be replaced with a motor would draw 11KW assuming 80% efficiency of the controllers etc. At 48V that would be 229A, so for 1hr at full power you would need about 500AH of battery (lead acid max discharge 50%).

If you want to be green, buy biofuel.

Look at golf cart batteries. Designed for a bit more than 50% drop . Come as 6V I believe but H duty

Thread: RENAULT DAUPHINE
01/08/2019 06:55:07

The TV advert, a film of the car with a big box on the roof & the family inside.

"It holds the road whatever the load, it's the Renault Dauphine"

Thread: Up and over door seal
30/07/2019 13:30:13

I had a brush seal but it was useless as the water just goes through the brush. i now have a 100mm piece of damp proof membrane fitted to the door ,faced with a 20 mm wide strip of aluminium to clamp it to the door. There is still a small leak each end but the DPM has been left a little long & I have cut notches in the frame to accept this, so leakage is really very small

The best solution would be a piece of timber plugged & screwed to the floor inside, on a bed of mastic, to form a simple rebate. This would catch any water running down the door jambs, as well as under the door

Thread: Aldi bargain laser level
16/07/2019 07:56:15

Jason

Apologies

I did try to delet the last post when i realised it was totally out of context but the edit was stopped

sorry

15/07/2019 22:03:01

I am beginning to recall the method now. One doubles the angle & forms a triangle with 2 equal angles at the base & the top angle is  the observed sextant angle- (or is it twice the observed angle, or was the base angles each half the observed angle- cannot recall?). The base being the line between the 2 observed points. From that top point one strikes a circle through the 2 stations. But i seem to recall that one had to know which side of the stations one placed the triangles. Trial & error based on dead reckoning. Or obvious from the position of the land I think !!

Now I am going to have to find a b..y book & read it up for no other practical purpose other than reminding myself how !!!

Trouble is that reading a sextant horizontally through 2 points is almost impossibly on any small yacht in any sort of sea. The method possibly stemmed from the days of square riggers with a stable platform. There was also a special protractor for setting out the triangles. Forget the name. Will have to sleep on that one.

Edited By Sam Longley 1 on 15/07/2019 22:46:41

15/07/2019 20:55:43
Posted by andrew lyner on 15/07/2019 20:04:37:
Posted by Sam Longley 1 on 15/07/2019 20:02:03:

I would back the accuracy of my Sestral Handbearing compass aimed at a single point up against my sextant held horizontally, whilst trying to fix on 2 points any day.

You don't have to "fix on" two points. You adjust th sextant until the two objects coincide. It doesn't;t matter if they are jigging about.

What sort of accuracy can you rely on with your hand bearing compass and have you ever tried a HSA reading?

You have just said something that conflicts-- that you have to get 2 points to coincide. Of course it matters if they are jiggling about. have you never tried tossing about in a swell aiming a sextant at a target. I have enough trouble aiming binoculars in a 2 metre chop, let alone aiming my sextant at 2 shore targets at once. I have to admit that my sextant does not lend itself to horizontal use, I have had it 40 years & it does not have wheel adjustment. I certainly have tried( just testing really) & given up as a bad job. Easy vertically. Lack of use in the last 20 years makes it difficult to pick up now

My Sestral compass is about as good as they get & i can get fairly good top hats depending on boat motion.I use it regularly in places like Channel Islands

To each his own- we are not going to agree- but does that matter- Of course not yes

15/07/2019 20:02:03

I would back the accuracy of my Sestral Handbearing compass aimed at a single point up against my sextant held horizontally, whilst trying to fix on 2 points any day.

15/07/2019 19:24:15
Posted by Frank Gorse on 15/07/2019 18:56:03:

Quite right.one horizontal angle needs a compass bearing to give position. Two horizontal sextant angles on three objects gives a fix where the two arcs overlap and both were still in the textbooks for RYA yachtmaster not that long ago but I’ve never tried either.and shouldn’t want to have to when it really mattered.

 

With the greatest respect, Are you sure about that?

Somehow I do not think that would give a reliable fix.The RYA method uses 3 compass bearings not a sextant angle If one has a sextant one has to work from a point towards the targets

One would have to lay the compass bearing line first then set the angle with a protractor or similar tool & slide it along the bearing line until it met the target. Repeat for the third point. The whole fix would be totally reliant on the first bearing, thus making the fix very unreliable. If one had a compass to take the bearing in the first place then one would continue to take bearings.

If you think about it, there is no advantage in using a sextant which is not only difficult but would produce an inconsistent fix.

Edited By Sam Longley 1 on 15/07/2019 19:27:30

15/07/2019 19:06:18

My first "foreign trip" from Burnham on Crouch to Ostend was in 1969 & I missed Ostend by 9 miles (no lessons for me) I hadn't a clue where I was.

I have just returned from 6 weeks single handed cruise to the Channel islands (picking up the June 06 D day landings on the way) & just as I left, my chart plotter failed. The best part of the trip was having to manage the navigation conventionally. Especially 2 legs of approx 100 miles - part over night,out of sight of land-, wondering where on earth I would end up. The rocks around Channel Islands tend to focus the mind .

Spot on every time- So what I learned all those years ago still worked.

Edited By Sam Longley 1 on 15/07/2019 19:07:07

15/07/2019 16:45:58

A Horizontal angle on its own will not give you distance off because it will subtend an arc which could be any distance from the shore dependent on the length of either leg. You need a compass to determine the direction of the legs. In which case the sextant is not required. Without the compass bearing you would not know where to draw the lines.

However, Charts show the height of light houses which gives the third dimension of your triangle for distance off if you take the angle vertically. You need to be able to see the base & know the height of tide then you can calculate the distance to the object That is unless you know the dipping distance, in which case the vertical angle is irrelevant. But you still need to know the bearing from the light to get a position fix within a reasonable estimate.

The "dipping distance" is the distance at which the light appears to drop below the horizon.Add to that, the dipping distance of the observers eye above the waterline & you have an approx distance off.

Better still if you have GPS & it is not being jammed

Edited By Sam Longley 1 on 15/07/2019 16:47:42

15/07/2019 08:03:15

But a laser level, which is a very common use for them, could be pointing up in the air (or down)

 

Edited By Sam Longley 1 on 15/07/2019 08:05:45

15/07/2019 07:29:28
Posted by Neil Wyatt on 15/07/2019 01:13:37:

 

I'm sure (most) younger readers will struggle as much to know what Dumpy and Cowley levels are*.

Neil

Of course they are antiques now & consigned to the bin.(mine is not, I used it last year) But when Paul used a laser to align his fence & drains he could possibly have used a set of boning rods to far greater effect.

My grandfather was using water levels as did his grandfather before him & mine is hanging in the shed. But ask someone how to fill one (they do not work if they have air bubbles in them) -- there is another question for you

But should they assume that because it is a " laser" the instrument supplied is adjusted for accuracy in the first place? & just because it is modern it does not always make it the best tool for the job

Edited By Sam Longley 1 on 15/07/2019 07:38:49

14/07/2019 07:20:18
Posted by Paul Lousick on 11/07/2019 23:18:46:

Its a laser pointer with a bubble level and not a precision instrument if you only rely on the bubble.

I used one to determine the levels for the storm water drainage piping around my house and because it was on fairly flat land, could only achieve a fall of 1 in 100. Prior to using the laser, I used a length of clear plastic tube, filled with water to mark datum points at several positions around my house and used these points as targets for aligning the laser. Then I could swing the laser between the datum points and measure the depth to the trench for the water pipe.

After the pipes were installed, a council building inspector told me it had to be checked by a certified surveyor. Luckily the cheap laser level and water filled tube did their job and the project was passed.

Paul.

That brings back memories.

When I was 10 years old my fathers foreman ganger used to let me sight down the boning rods when drain laying.

Salt glazed drains with cement joints..

Datums were set with a Cowley level.

Still would not mess about with a laser if there was 2 of us.

Still got the dumpy level & staff he let me buy for my own use when I was 16. An antique now I suspect.

If a building surveyor told me that i had to have a "certified surveyor" to check my drains I would have told him to get stuffed- (Regardless of the fact I am qualified anyway, it would not matter)

One of the questions I used to ask site foremen when interviewing them was, "Can you use a dumpy level" Answer " yes" - OK

Do you know how to check it for accuracy? That used to stump some of them & I suspect that lasers, when hired, borrowed etc. would not necessarily be accurate. Most would just assume they are. But hired equipment gets abused.

I have never used one in anger; but if i did I would know how to check it.

I wonder if others have had the problem- is it an issue with lasers?

So here is a question for you.

How would one check a "hired in" laser for accuracy prior to use?

 

Edited By Sam Longley 1 on 14/07/2019 07:30:33

Thread: Rudder Bushes on Boat
15/05/2019 07:22:11

Before beginning to make rudder bearings it may be worth looking on this site. Jefa make roller bearings for a wide range of craft & by the time one has invested in the material one could have bought a ready made bearing

**LINK**

But in any event do NOT use nylon. I use tufnol in my rope cutter bearings, but in rod form, can be very expensive-- depending on diameter, of course

 

Edited By Sam Longley 1 on 15/05/2019 07:25:32

Thread: Anglepoise Lamps & CFL/LED lamps
07/05/2019 16:52:44
Posted by Peter G. Shaw on 05/05/2019 19:33:55:

Following on from the thread about Lathe Lights & the Anglepoise copy. I have a many year old genuine Anglepoise which was originally designed to take either 40W or 60W, can't remember which, incandescent lamps.

At the moment I have a 9W LED installed which is somewhat heavier than the incandescents such that the springs are just that bit too weak to hold it in the set position and the light slowly but surely drifts downwards.

Thoughts please.

Peter G. Shaw

Keep it for a few more years. You will find that after a while, you will tend to drift down with it as the day goes on.surprise

Thread: "Screwing" a car round a corner!
27/04/2019 20:30:53

Mythbuster's investigated drifting to see if it was the fastest way to get round a race course. It's not. Although good fun and looks cool, it's slower than cornering conventionally. They didn't compare tyre damage, but I suspect drifting is murder on the rubber.

Dave

Perhaps they should have watched John Rodes cornering the works Cooper S at Druids (Brands Hatch) when he used to sling the back of his mini out wide by flicking the hand brake then squirting the throttle to get it to head down the hill towards South Bank

Thread: Dol starter or just a plug is it really worth it?
26/04/2019 08:05:46
Posted by Emgee on 25/04/2019 20:28:48:

Grant, whichever method you use it is best to consider an easily accessable Emergency stop type button to switch the spindle motor off in case of an emergency when you are using the lathe, it could safe you serious injury or even worse,

Emgee

What? worse? you mean as in damage a couple of days work??sad

Edited By Sam Longley 1 on 26/04/2019 08:06:23

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
Ausee.com.au
Eccentric Engineering
Meridienne Sept 2019
Advertise With Us
ChesterUK
Warco
TRANSWAVE Converters
Eccentric July 5 2018
emcomachinetools
Allendale Electronics
Subscription Offer

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