# Making Safety Valves.



## Tony Bird (Oct 22, 2012)

Hi,

Having constructed several boiler,  fittings for them need to be made.  Normaly these fittings are made in batches but none are left.  Some months ago I bought an inexpensive Chinese tail stock turret.  The last time I used one was when I was an apprentice!  The turret was modified to suit my Myford lathe and has had some use producing boiler bushes and gas regulator valves which now means that it is now up and running.  Yesterday a start was made making the bodies for safety valves, this is the first time that all 6 stations of the turret have needed to be used. The turret though fairly cheap to buy costs a lot more to fill ith Jacob chucks and tool holders. I have found the turret very useful and quick but I make all of my own fittings usually in multipules.  The following photographs show the sequence used making 12 safety valve bodies each body took about 10 minutes to make and the set up of the turret about 40 minutes.






Turret set up.




Marked out.




Centre drill.




Tapping drill.




Drill for steam entry.




Drill to make bottom of hole flat.




Tapping.




Turning sholder.




Parting off.




Turning shoulder for thread.




Threading.




Finished.

For those interested the internal thread is 1/4"x 40tpi the exrernal 3/16"x 40tpi.  With the bodies finished its the srew that holds the spring in next.


Regards Tony.


----------



## Herbiev (Oct 22, 2012)

Thanks for sharing that Tony. I have never seen one of those turrets. Where did you get it?


----------



## Tony Bird (Oct 22, 2012)

Hi Herbie,

It has no brand name.  I got it from a company called Arc Euro Trade in the UK.  They do have a web site.

Regards Tony.


----------



## Tony Bird (Oct 22, 2012)

Hi,

Finished making 12 safety valves adjusting srews.  The photographs should show how they were made if not please ask.














































Rods to be made perhaps tomorrow.

Regards Tony.


----------



## lee9966 (Oct 22, 2012)

Tony, can you comment on the depth stops on the drills? Do they have just one locking screw?  I would have thought that could just happen to land on a position on the drill where it would just catch an edge on the spiral and tightening the locking screw would move the stop a bit off where you want it.  Am I dreaming up an issue that doesn't ever happen?

Thanks for showing the turret, quite nice.


Lee


----------



## Tony Bird (Oct 23, 2012)

Hi Lee,

There doesn't seem to be an issue with the 3mm locking screw, it either does or doesn't fit into the slot of the drill or tap.  It is possible that there might be a problem with when it just doesn't go into the slot but as yet I haven't had a problem.

Regards Tony.


----------



## SilverSanJuan (Oct 23, 2012)

Great stuff Tony.  Thanks for posting this.

Todd


----------



## Tony Bird (Oct 24, 2012)

Hi,

I managed to complete and test one safety valve yesterday.  Decided to try and make a semi 'Pop' type.  One of my larger locomotives is a 5" gauge saddle tank with one safety valve.  In recent years with more stringent boiler testing regulations being applied it was a mute point whether the safety valve would keep the boiler within the 10% increase in pressure allowed.  In the UK safety valves on model boilers above the 3bar limit must not allow the boiler pressure to increase more than 10% above the boilers normal working pressure.  This is done with the locomotive stationary and the blower full on.  I was about to make a new safety valve for the boiler when a member of our model club said that he had seen an article in the ME on altering a standard safety valve to a semi 'Pop'.  These valves release more pressure more quickly than the standard designs.  They open and close very quickly with a 'Pop' and do not allow the pressure to drop very far.  The alterations to the safety valve of the large locomotive worked very well its working pressure of 90psi only increasing by about 5lbs during tests not the 9/10psi of the original valve.
Not that I think a 'Pop' valve is necessary for small boilers but it would be a bit of fun to see if one could be made to work.  Results in video below, more of a phut than a pop but it is quite a low pressure.






Regards Tony.


----------



## skyline1 (Oct 24, 2012)

Hi Tony

Those safety valves look familiar are they the old "LBSC" design from many years ago. They are very reliable and just do the job. I have made several of them myself.

Great example of how to mass produce things like this I might investigate one of those turrets myself. I presume that it is not self indexing like a capstan turret.One of these would be great for doing union nuts as they are getting pretty expensive now. Anyway it's much more fun to make your own especially if you can mass produce them like this.

Regards Mark


----------



## Tin Falcon (Oct 24, 2012)

> Thanks for sharing that Tony. I have never seen one of those turrets. Where did you get it?



IIRC most of the tool importers sell those. enco, LMS, shars cdco, ..... not expensive. they do require some time and tool making to set up .

you can use bushings instead of drill chuck to save z axis space. 

a nice set up saves time changing tail stock tools easier than building a capstan or turret. .
tin


----------



## GVH (Oct 24, 2012)

Tony....nice post....thx


----------



## Tony Bird (Oct 24, 2012)

Hi Mark,

*Those safety valves look familiar are they the old "LBSC" design from many years ago. They are very reliable and just do the job. I have made several of them myself.*

They are a similar design to LBSC's and many other peoples, they are my own design as much as it is possible as it to design a safety valve.  I did do the volume calculations and probably came to the same results as many others.

*Great example of how to mass produce things like this I might investigate one of those turrets myself. I presume that it is not self indexing like a capstan turret.One of these would be great for doing union nuts as they are getting pretty expensive now. Anyway it's much more fun to make your own especially if you can mass produce them like this.*

The turret does idex but not like a lever operation like on a Capstan lathe.  A lever is pressed and the turret moved around by hand.   I am very happy with my purchase because I sometimes make a lot of the same bits.   I have a long bed lathe which was an extra £27 when it was bought a long time ago.  The turret does take up quite a lot of room and would take up quite a lot of room on a standard length Myford.   But as has been suggested bushes could be made up to replace Jacobs chucks which would shorten it but the tap and die holders are quite long.  As a draw bar cannot be used in the tailstock so I have fitted a set screw to stop the turret rotating on its Morse taper.











Regard Tony.


----------



## Tony Bird (Oct 24, 2012)

Hi,

This is the difference between most safety valves and the semi 'pop' variety.  The usual valve is on the right and the recently made 'pop' on the left.   As can be seen the ball is in a cup on the pop valve and in the open on the other.  The ball in the cup is a good rotating fit.  When the ball fits in the hole in the valve body the edge of the cup is only a few 100ths of a mm off the valve body.  It works (I think) as the steam pressure increases the ball lifts slightly and instead of going directly to atmosphere the steam acts on the inside of the cup and given this extra area opens the valve quickly with a distinct 'pop'.  The valve also seems to close quicker and doesn't seem to weep as much as the usual type of safety valve.   








Regards Tony.


----------



## Tony Bird (Oct 24, 2012)

Hi,





Marked out.




First cut.




Second cut.




Third cut.




Forth cut.




Parting off.




Needing facing and drilling.




Facing.




Drilling.




Adjusting ball depth.




Adjusted.




Ball depth jig.




Maximum amount of clearance.




Seven of the twelve safety valves used.

The tailstock turret has now been used to make Goodall water filler valves, gas poker burners, gas control valves and now safety valves for the above boilers with a couple of each components spare for other models.  Still to be made are gauge glasses and steam regulators.  But a little time off on other jobs first I think!


Regards Tony.


----------



## ChooChooMike (Oct 24, 2012)

Nice collection of boilers !!


----------



## pandy (Oct 24, 2012)

I see you are using a vertical hold  tool bit holder for this project. Is there any chance that you could post details of source, dimentions or even a photo

Many thanks 

Pandy


----------



## Tony Bird (Oct 25, 2012)

Hi Pandy,


*I see you are using a vertical hold  tool bit holder for this project. Is there any chance that you could post details of source, dimentions or even a photo*

I have used what is known as a Diamond Tool Holder for more than twenty years and I am am very happy with it.  Mine came direct from Australia but there is now a UK importer.  See.

http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=2&Itemid=17

I wish they made a right hand version of it and a square on one would be useful as well.

Regards Tony.


----------



## Tony Bird (Oct 25, 2012)

Hello again,

Just had a look at the DTH site they now do make a right hand  version which I will order.

Regards Tony.


----------



## pandy (Oct 27, 2012)

Thanks for the info, Tony, I have had a look and will be placing one on my Christmas list!!!

Pandy


----------



## skyline1 (Oct 27, 2012)

Impressive collection of boilers Tony. Now I know why you need so many safety valves If you fired up all of 'em at once I'd see the cloud of steam from this side of the Severn.

Regards Mark


----------



## Beachside_Hank (Oct 27, 2012)

Tony Bird said:


> Hi,
> 
> This is the difference between most safety valves and the semi 'pop' variety.  The usual valve is on the right and the recently made 'pop' on the left.   As can be seen the ball is in a cup on the pop valve and in the open on the other.  The ball in the cup is a good rotating fit.  When the ball fits in the hole in the valve body the edge of the cup is only a few 100ths of a mm off the valve body.  It works (I think) as the steam pressure increases the ball lifts slightly and instead of going directly to atmosphere the steam acts on the inside of the cup and given this extra area opens the valve quickly with a distinct 'pop'.  The valve also seems to close quicker and doesn't seem to weep as much as the usual type of safety valve.
> 
> ...



  Your theory of operation is correct as far as I know. I remember in Boilerman school while in the Navy, the seating area of the safety was designed to pop at a given pressure, in the case of our ships boiler that was 610 p.s.i. What the internal flange did was increase the surface area such that the escaping steam would hold the valve open until a lesser pressure was achieved, something like 580 p.s.i. if I recall; simple, reliable, very few moving parts.


----------



## locoman (Nov 10, 2012)

A most informative and well presented thread. And very clear photographs! Well done.


----------



## Luke (Nov 6, 2018)

Great instructive thread and posting Tony, Thank you very much. I'm using your guide to make several myself. One tiny question regarding the used 'ball' what can you suggest where to locate them, or just use some scrap from old ball bearings ?
Thanks,
and Best Regards,
Luc


----------



## Tony Bird (Nov 7, 2018)

Hi Luc,

The balls are stainless steel and I get them from am model engineering suppliers here in the UK; I often use Blackgates Engineering.  I don't think it would be a good idea to use steel balls I have used bronze balls which are also available but I usually use stainless steel.

Regards Tony.


----------



## Buzbey2014 (Nov 7, 2018)

Hi,
Can you tell me which ME had the info on converting safety valves you mentioned?
Thanks
Ken


----------



## Luke (Nov 7, 2018)

Tony Bird said:


> Hi Luc,
> 
> The balls are stainless steel and I get them from am model engineering suppliers here in the UK; I often use Blackgates Engineering.  I don't think it would be a good idea to use steel balls I have used bronze balls which are also available but I usually use stainless steel.
> 
> Regards Tony.


Tony,
Thanks for the info. I will try to get some over here.
Cheers,


----------



## Tony Bird (Nov 7, 2018)

Hi Ken,

*Can you tell me which ME had the info on converting safety valves you mentioned?*

I tell fibs!  It wasn't the ME that had the article but Engineering in Miniature July 2006; it was titled 'SAFETY VALVES-Some alterations in designs' by Gordon Smith.

If you cannot get a copy email me direct [email protected] and I will send you a scan. 

Regards Tony.


----------



## Jennifer Edwards (Nov 9, 2018)

Thanks for sharing this with us. 

That is a really great Turret Lathe. When I actually made a living as a machinist, I loved when I had use of an accurate and powerful turret lathe for multiple part runs. It made life so much easier.

Nice job!


----------



## goldstar31 (Nov 9, 2018)

I see that ArcEurotrade still sell one at £78-ish but Lawrence Sparey writing in the Amateurs Lathe book published drawings.

I've a turret for the bed  on the Myford Super 7--  but have never used it. Cost me about £45 second hand.

For those who want one, Ken Metcalf wrote details of his which fitted his ML7 in Model Engineer.

Norm


----------



## fcheslop (Nov 9, 2018)

I made this unit with a few mods .Mainly to the locating plunger on my version it is tapered in the hope it compensates for wear n tear
http://www.projectsinmetal.com/foru...w-project-plans-for-a-lathe-tailstock-turret/
I keep thinking about using a flat seal as per small commercial  safety valves but have not got round to trying it
Nice work Tony 
cheers


----------



## Jennifer Edwards (Nov 9, 2018)

Thanks Norm,

at the moment I am using an Axminster SC2, basically a 7x12, so it is quite small to fit a turret to. 

But a gal can dream!


----------



## goldstar31 (Nov 9, 2018)

Jennifer Edwards said:


> Thanks Norm,
> 
> at the moment I am using an Axminster SC2, basically a 7x12, so it is quite small to fit a turret to.
> 
> But a gal can dream!



Apart from the length between centres, your SC2 is not much different to his ML7.
I was hoping to remove the tailstock on my slightly larger Sieg C4 now fitted with a Vertical Mill which ----won't work.  I would guess that Ken Metcalf's  turret would give you more room.
Drop me a note if I can help

Regards

Norm

PS. I'm still dream at 88!


----------



## Jennifer Edwards (Nov 9, 2018)

goldstar31 said:


> Apart from the length between centres, your SC2 is not much different to his ML7.
> I was hoping to remove the tailstock on my slightly larger Sieg C4 now fitted with a Vertical Mill which ----won't work.  I would guess that Ken Metcalf's  turret would give you more room.
> Drop me a note if I can help
> 
> ...



orm,

I had no clue that they made one small enough for my lathe. I just had to cut four parts that required three different cutters and a die. it woud have saved me an additional 12 setups if i had one. I will see if I can suss one out. If I strike out I wil drop you a line.

Thanks again,
jen


----------



## goldstar31 (Nov 9, 2018)

I hav e macular  degeneration but Metcalf- as far as I can see, made the turret out of a hexagon with sides 3.75 and the block was 1.5" thick. Again, he talked of lathes other than the mentioned Myfords.

I printed it out - in case?

N


----------



## Jennifer Edwards (Nov 9, 2018)

I would love to read it, do you have a link?


----------



## fcheslop (Nov 9, 2018)

Is this of any use
apologies to Tony for taking his thread of topic
http://mikesworkshop.weebly.com/tailstock-turret.html


----------



## goldstar31 (Nov 9, 2018)

Deleted-  sorry!


----------



## abby (Nov 9, 2018)

This is the ideal machine for mass producing small parts.




It's a Pultra 1750 with capstan turret and cut-off slide.
I collected the basics over a couple of years and built a bench/cabinet.
The 3 phase motor is housed in the cabinet and has inverter control.
I am looking out for a clutch to avoid switching on/off between parts which can be time consuming and not good for inverters.
A mechanical collet closure can also be obtained , along with a bar feed this becomes a serious piece of kit.
Once set up I can safely make a hundred parts without inspection which is helpful.
<iframe width="560" height="315" src="" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
These are banjo connectors for a steam loco boiler feed pump I was designing.
It is easy to get carried away though and make loads more bits than you can realistically use.
Dan.


----------



## fcheslop (Nov 9, 2018)

deleted not relevant to thread


----------



## the artfull-codger (Nov 10, 2018)

Hi Tony, I too have a tailstock turret,mines about 45yrs old & they're really usefull, I notice you using your "diamond" turning tool,I also bought mine from australia I have lh & rh & their parting tool all great quality, one thing puzzles me is are you using it on brass or bronze safety valves? I tried mine on brass once & it self feeded in really bad, I was tempted to grind it flat but never bothered as I have tools with no top rake for brass, nice valves & models btw.
Kind Regards
Graham.


----------



## goldstar31 (Nov 11, 2018)

Jennifer

Whilst looking for 'Flash steeam' information,  I ran across D.M Hughes of his very simple tailstock turret.

Model Engineer  July2  1953-- if you must

Interested??

Norm


----------



## tomfilery (Nov 17, 2018)

Hi Tony,
Could you please say a little about the ball seating jig you show in post#14.  I expect it's use is fairly self evident, however, what wasn't clear to me was how you determine the "maximum clearance" - by the angle of the valve stem, by measurement with feeler gauges, or something else and what the 2.9 stamped on the jig referring to?
I ask the questions because I understand that the clearance (i.e. how far the ball protrudes from it's carrier) is critical to the correct operation of this type of safety valve.
Nice work and an educational post, as ever.
Regards Tom


----------



## Tony Bird (Nov 25, 2018)

Hi Tom,

Sorry for the delay in replying to your query but only got back to the UK early this morning and for some reason didn't get a notification of your post while away.

*Could you please say a little about the ball seating jig you show in post#14. I expect it's use is fairly self evident, however, what wasn't clear to me was how you determine the "maximum clearance" - by the angle of the valve stem, by measurement with feeler gauges, or something else and what the 2.9 stamped on the jig referring to?
I ask the questions because I understand that the clearance (i.e. how far the ball protrudes from it's carrier) is critical to the correct operation of this type of safety valve.*

The 2.9 on the jig refers to the size of the hole that the ball sits in.  The size hole means that a 5/32" (4 mm ish) ball will be resting in it on its radius.  This measurement is arrived at by dividing the balls diameter 3,969 mm by 1.41 which gives 2.815 mm and I usually use the next drill size up.  I have always done this when making safety valves, I must have read it in the ME in the dim and distant, it seems to work.  The clearance of the cup needs to be very little about 10/15 degree lean or as little as can be managed and the ball still seats.  I seem to remember that the article I read about making them suggested 5 to 10 thou clearance possibly to allow for wear?

I hope this helps.

Regards Tony.


----------



## tomfilery (Nov 26, 2018)

Tony,

Many thanks for the response - crystal clear, thank you.

I'd picked up from the Ceramic Burner thread that you were in Madeira, so wasn't expecting an immediate answer.

Regards Tom


----------



## Lois Flakes (Mar 5, 2019)

Yeah!! These are the impressive boilers.


----------

