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Member postings for S.D.L.

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

Thread: Thread Size
24/11/2014 18:31:49

Posted by Jack Foreman 1 on 24/11/2014 09:39:54:

A bit of a shot in the dark.

Can anyone, offhand, tell me the size of the internal drawbar thread in a Clarkson 30INT chuck please? I have to make the drawbar for the mill to secure the chuck.

Thanks
Jack

I have seen M10, 3/8 BSW, 3/8 UNC, M12 and 1/2 BSW, and I expect there was 1/2 UNC as well. I brought some threaded rod back from the U.S. for the UNC one.

Try some bolts or if very carful some Taps to try them.

A lot of auto locks have the size in very feint writing on the side, if tarnished try cleaning up wit a bit of WD40 and fine scotchbrite.

Steve

Thread: Boiler thickness and pressure
24/10/2014 18:36:15
Posted by JasonB on 24/10/2014 15:24:04:

From SDL's posting the temperature is taken account of by a separate allowance and the safety factor remains the same at 8.

J

The martin Evans book that I took this from has good worked examples and certainly the tube thickness is what is in the Northern association guidelines. Note these design guidelines are separate from the testing book. This should not stifle developments but few boiler inspectors are going to have the experience to review FEA but this should not stop people adding blind bushes for fixings of door runners etc

Please spare a thought for your Boiler inspectors, many do a thankless job, at the end of the day its them that has to sign off and pass things. At our club for many years the boiler inspectors thought they were covered by the club insurance, It was only when I raised a question in writing during the review before the last code change that it was made clear that the club needed separate indemnity insurance for the boiler inspectors otherwise there assets are on the line. as you could imagine we took this out promptly. This insurance is shown on the southern fed form but historically the implications had not been understood.

Steve

24/10/2014 13:24:20
Posted by JasonB on 24/10/2014 11:26:54:

SDL would it be possible to put some figure sinto that formula particularly the stress value that you used as that seems to be one of the big variables.

Figures I used are shown below from my spreadsheet based on Martin Evans book which are the same as the Northern Association guidelines I mentioned earlier.The .9 join allowance is what I would allow, drawn tube is 1.

this gives .091" or 2.32mm

 

Steve

Barrel thichkness

Source

Model locomotive and marine boilers

By Martin Evans

ISBN 1 85761 138 1 P28

Where

P Plate thicnes in inches

D OD of Barrel in inches

 
F Factor Of Saftey 8
 
WP Working pressure PSI
 
S Ultimate tensile strength cu 25000 psi cs 60000 posi ss 70000 psi
 
R Riveting allowance single rivet = 0.5 double rivet 0.7 silver solder=0.8
 
C Corrosion allowance cu 0 ss 0 cs 0.5
 
T Temperature allowance <100psi = 0.8 100-150psi = 0.7
 
 
I used as below
 
 
  P =     0.091 "
when D 5.875 " OD      
  8        
  WP 70 PSI      
  S 25000 PSI      
  R 0.9 Joint Factor    
  T 0.8 Temperature Factor    

 

Edited By S.D.L. on 24/10/2014 13:26:06

24/10/2014 10:58:13
Posted by fizzy on 23/10/2014 21:55:00:

Hi Julian. I can assure you that I am far from bonkers! The fact remains that there is a published and accepted formula which if applied to the letter would allow the use of the gauge I referred to. As a scientist I can either accept the formula or reject it. It is either right or wrong and the fact that no one has published a boiler to this specification is completely immaterial to the fact. I have no intention of building said boiler without thorough understanding, but as yet I have not seen a single argument which in any way proves the formula to be wrong. Indeed if we had never departed from accepted standards we would still be building wooden battleships and car bodies would be made of 1/4" steel plate. I openly welcome constructive input and criticism but without supporting evidence it is merely an opinion and they don't stand up to scientific scrutiny. I still fail to understand upon what grounds an inspector could fail the boiler other than he didn't much like the look of it. Why should it be rejected if it satisfies published and well used formula?

Hi Fizzy

The answer that I posted earlier was based on the Martin Evans formula. I have been rooting around in my workshop and found a guidance note titled.NORTHERN ASSOCIATION OF MODEL ENGINEERS BOILER INSPECTORS SEMINAR. Boiler Design Materials Calculations. In this they recoment that the Martin Evans formula of

P=( D*F*W.P)/(T.S.*R*C*T*2) be used

Now if I was a Boiler inspector at a club in the northern federation that is what I would use until the guidelines were changed.

On a different note, I have never used a strength of 1 on welded joint design even with coded welders hence my use of .9. When you were coded did the welds still have to be x rayed on butt welds and dye pen on fillets?

Steve

21/10/2014 13:13:05
Posted by fizzy on 20/10/2014 14:55:04:

Im fast aproaching completing my 71/4 invicta. Now moving to the boiler design phase. Im planning on using copper for this, the thinner the better as far as construction ease goes (TIG Welded) so I put the following for discussion:

ID is 5.625"

Using 3125lb/in (safety factor x8) and 16g tube I can run WP 70psi.

Is 70 psi likely to be enough pressure or will I need to calculate this also?

Can i justify a lower safety factor?

Thanks

Using Martin Evans numbers I get minimum 0.082" wall allowing a .9 factor for the Tig butt weld.

Silver solder lap joint would be 0.8

Steve

Thread: New addition to the family.! ;)
17/10/2014 12:09:41
Posted by magpie on 17/10/2014 11:55:19:

Nick, if the head is nice and square on, leave it where it is and buy a tilting table or a tilting vice. Unless of course you don't mind spending ages traming the head up again every time you tilt it.

Cheers Derek.

Surely the reason for the tapered dowel is to give correct alignment???

Steve

Thread: Clamps,
30/09/2014 10:26:21
Posted by XD 351 on 30/09/2014 02:59:39:

There isn't much in making making them yourself mostly basic metal work with a bit of turning and threading thrown in - a good beginners project maybe?

Ian

That's why I posted asking if anyone can remember what magazine an article has been in. Several members at our club want to make some and although I have 1 clamp to copy I remember an article in one of the magazines but cant remember if it was in ME / MEW / EIM or one of the US magazines Home Shop Machinist or Machinest Workshop.

Steve

29/09/2014 20:14:01

Posted by PeterGee on 19/02/2013 11:27:59:

Here is a photo of one of my own Crab Clams:

Crab Clamp

The preview shows the photo as rather distorted, but the background should help work out the true aspect ratio of the photo... I hope.

Does anyone remember an article in one of the model magazines about making clamps to this design.

Steve

Thread: Possible leadscrew nut for light duty machines.
02/09/2014 15:42:04
Posted by Neil Wyatt on 02/09/2014 13:47:38:

This might be a stupid idea, but i was playing with some nylon fixit blocks.

I managed to get an M6 screw into the single hole. After filing a notch in the end of the screw and making several traverses the hole became reasonably free and tidied itself up.

Result? An ordinary M6 screw (without notch) or M6 studding gives a lightly stiff but totally backlash-free nut that could be used under light loads for a 3D printer or grinding machine.

The only downside is that after a few hours stationary it develops a bit of 'stiction'.

Possibly using an undersize taper tap a freer but still usable result could be got. Another option might be working some teflon grease into the thread.

Neil

There is a big discussion here

**LINK**

there might be another thread as well

Steve

Thread: Not a "modeller"!
24/08/2014 10:23:10
Posted by Bill Pudney on 24/08/2014 02:42:17:

To throw another spanner in the works, with my tongue slightly in my cheek, the continual use of the term "Engineer" to describe a person who makes things out of metal, floats my boat. To me that person is a machinist, fitter, sheetmetal worker etc. An Engineer is someone with a Degree in an appropriate discipline, he or she may well practice the art of machining, fitting, sheetmetal working etc etc, but they are also capable of doing the various "Engineering" things, like stressing, complex calculations etc etc.

cheers

Bill

The distinction is if they can do the calculation and analysis not if they have a Degree. I stopped my education at HNC as by then I was married and had a mortgage. I currently spend a fair amount of my time developing sizing tools for our equipment based on the results of validation reports. These reports are usually done by Engineers with masters or PhDs yet still I keep finding them full of errors.

The degree only proves that they are clever enough to pass the test not give them an automatic right to engineer staus. Having started off in a Drawing office where all the Designers were HNC / HND and doing all the design and stress calculations, whilst the Engineers sat in a separate office as project managers and couldn't organise a Pi$$ up in a brewery.

Steve

I Like the name model engineers workshop.

if there is so many motorbike and car fans that want garage articles why haven't they got there own magazine?

23/08/2014 14:57:40
Posted by John Billard on 23/08/2014 11:43:19:

I hope this is the right place to air a minor sore point. That is the description "modeller" for ME readers as in the latest ad for the next issue. We are engineers, not practicing in "modellers" clay, nor are we on a cat walk!

This complaint goes back a long way as I have read that old LBSC refused to use the term "model" preferring the word "miniature".

Kind regards to all - including the editor!

John B

The magazine has been called Model Engineer for decades probably since the good old days whenever that was. I much prefer the term Scale Model when talking about a scaled model of a prototype. A model maker used to be one of the top trades in many companies. miniature suggests to me dolls houses etc and reminds me of steam fairs and the miniature parade with the explanation that whitworth threads live on as camera tripod mounts when it has been UNC for years.

it was natural when MEW was spun off from model engineering to call it Model engineers workshop to try and keep the original readers. Most of the famous old names, Thomas, Radford, Etc etc. We're making tools to improve there models.

Since the spin off others have come in, some such as the famous Sir John (I want my 2 quid back) have brought a whole new range on tools customised for home workshop use through Arc and others. So things evolve and change but I don't expect the publisher to play with the brand name, remember Royal Mails new name??

Steve

Thread: Collets help
04/06/2014 19:14:50
Posted by Roderick Jenkins on 04/06/2014 17:03:36:

Frank,

Putting such force on the collet nut that you have to hold it in a vice doesn't seem to be very kind to the collet or the chuck. My ER25 chuck has a spanner flat on it and I bought a 30mm spanner especially to fit. Even with a ball bearing nut, I regard the force required to close the collet on a 1/8" endmill as excessive.

Clearly your experiences differ from mine and the polite and non-aggressive way is to not call my experience nonsense.

cheers,

Rod

Edited By Neil Wyatt on 04/06/2014 18:23:03

Correct torque is about 75ftlbs, which normally requires a holding fixture. The bearing nuts are better .

This force goes up for ER32.

Steve

Thread: New kid on the block !!!
05/05/2014 18:54:19
Posted by Toys4boys on 02/05/2014 23:01:35:

Firstly, hello all !!!!

I've only just signed up here and can already see it becoming a very useful resource for the foreseeable future. Having Googled many engineering related subjects I have often stumbled across this site anyway, so joining up seems the logical thing to do having the benefit of everyone's individual input derived from personal experiences.

Anyway, I've been sorting out my garage workshop for the last few months, and sorted some nice kit, Colchester Chipmaster, Fobco star, AEW Viceroy vertical milling machine, AEW wet grinder, RJH Gryphon bench grinder/polisher (New old stock - eBay bargain !!). Along with the machines I've sorted out a large amount of quality second hand tooling so pretty pleased so far.

I've managed to sort out an operating manual for the lathe along with some other literature at no cost by downloading and printing out, but I can't seem to find any info for the milling machine other than the history on Lathes.co.uk. Does anybody have a manual for the this milling machine (vertical model) they are willing to part with or copy etc, or know where I could download one free. I know you can get them from Tony at lathes.co.uk, but rather pricey from memory (£40)

Any help or advice appreciated

Hi

As John Stevenson said I have a manual which I will scan in and email to you, have to be next week as I have just got back from a work trip and there isn't much time this week as it's Harrogate Friday .

drop me a pm and you will have it next week

do you have all the gears for the powder feed?

if yes can you give me the tooth count.

Glad to see another fan of the multifix tool holders as well.

Steve

Thread: Chuck for Rotary Table
01/05/2014 01:45:29
Posted by Danny M2Z on 30/04/2014 23:48:22:
Posted by ChrisH on 30/04/2014 20:04:13:?

Chris, for a four jaw chuck it's as good as your best dti and your patience.

Regards * Danny M *

Not when it's self centring.

Steve

Thread: Sherwood Jobber Drills - anything known?
01/04/2014 13:11:05

I bought a load of Sherwood roughing mills on offer in there sales leaflet and they were shipped direct from Sandvik so it looks like they buy in quality products.

I have had no problem with dormer since Sandvic moved the drills to Brazil and the end mills to Italy.

Steve

Thread: 71/4 wheel width?
01/04/2014 13:07:45
Posted by richardandtracy on 01/04/2014 10:56:42:

face 20

For some reason I find the idea of having a Euronorm for something as parochial as garden steam locomotives hysterically funny.

Is there no end to bureaucratic interference in inconsequential matters? [Don't mind me while I wipe my eyes.]

Standards are good, so why don't we have lots & lots & lots & lots of them? Oh yes, while we're at it, let's make sure they all change every 2 years too just to keep the money rolling in when people have to buy new copies of the standard. Scrub that latter idea, the British Standards Institute does that anyway.

Regards,

Richard

There must be at least half a dozen UK sets of standards 5" Gauge society 7.25" gauge society "O" gauge publish 3 or 4 standards finscale, coarse, etc. then you have S7 S4 EM etc etc

Steve

01/04/2014 13:04:33
Posted by fizzy on 31/03/2014 18:55:00:

Can I get away with an overall wheel width of 3/4 inch, and what is the norm dim for the flange?

You can download all the dimensions here

**LINK**

Looks like you might get away with being 1/16" short

Steve

Thread: Beaver mill
18/03/2014 14:01:45

Best hope is it was replaced with a more up to date and capable machine.

There is still lots of machining in this country, but to compete its got to be good metal removal rates unless used on repair work.

Steve

Thread: Buyer beware
11/03/2014 11:08:01
Posted by Russell Eberhardt on 11/03/2014 09:27:54:

Does anyone make drills in the UK now? snip

Russell.

Presto do, last time I looked

Dormer are still good wherever they are made with the ones I have had.

Steve

Thread: Different types of copper boiler tube
08/03/2014 21:46:39
Posted by Baz on 08/03/2014 17:38:44:

S.D.L. Receipts are pointless, all they prove is that on a particular day you purchased something. Julian Atkins boiler inspector should ask for Certificates of Conformity if he is concerned about the type etc of the material. By wanting a receipt all he is proving is that it was paid for and not nickedcheeky

Baz. The last lot of metal I purchased stated the section and the Material on both the delivery note and the Invoice (receipt) which I think is as good as a c of c, but if you want to go down the route of that might not be the right paper you will end up at PMI as many people will not accept mill certs nowadays in the commercial world.

The original point being argued was the contention that the boiler inspector does not need to check the material, I pasted the section where i think it shows the boiler inspector seems to know what he is doing.

Steve

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