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

Member postings for Stewart Hart

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

Thread: Tuna Can Blower
22/01/2020 13:49:57

Why do they call steam raising blowers when they suck ?. laugh

On with the mater in hand, I've tired various blowers and I found the best to be the ones made from 24V ex-military radio cooling vans you could get these quite cheep at one time but with scarcity they are getting expensive. And as is my natural curiosity I've stripped a fair number of blowers down. Then when making myself a lunchtime Tuna sandwich I looked at the empty tin and had the idea of making a blower out of it, I took the empty tin with us when we next went to the supper market looking for a suitable tin to make the inner fan out of to me delight I found that the smaller tins of Tuna they sell would just fit the bill. 24V electric motors are easy to obtain of the net.

A few manufacturing shot




Drilling the base of the fan the vanes were put in with a wood chisel whilst the inside was supported by a lump of wood.


The gap for the exhoust vent


The exhaust with its paper pattern


Soldering the exhaust


Machining the top and bottom plates these were made from 100mm dia ally blanks bought of the net.


Completed blower

And yes it does work I recon at that size it would be fine for smaller 5" gauge and 3 1/2, 2 1/2 locos

If you need a bigger blower you'd just have to find some bigger cans.



Edited By Stewart Hart on 22/01/2020 13:54:23

Thread: Stewart Hart
05/01/2020 11:39:27

Hi artful

Thanks for your interest in my helping dad mill engine there have been a lot built I hope you enjoy the build if you need the drawings just send me a pm with your email address


Thread: 2-6-0 Horwich Crab
23/12/2019 07:49:46

Well I guess its time for a progress update:- I've spent the last 12 months building the tender its now more or less complete just a little bit of tidying up required.




I'll crack on with finishing off the loco next year.


Thread: Beginners models
11/12/2019 18:30:14
Posted by SillyOldDuffer on 08/12/2019 09:39:55:

I always recommend Stewart Hart's Potty Mill engine : no castings, simple, but challenging enough to make you think!

Stewart is active on the forum and his engine is discussed in a number of threads, for example this one.

Plans available without bother: I used this found on the web without finding any mistakes. As technical drawings go it's rather cramped, and I believe Stewart provides better laid out drawings?

Possible negative for some, it's a metric design.

As a training exercise, I built one in Fusion 360, this image being when I was struggling to learn moving joints!

assembly v27.jpg


Edited By SillyOldDuffer on 08/12/2019 09:44:49

Thanks for your endorsement Dave. If anyone wants a set of drawings just send me a PM with your email address


Thread: Clutch type lubricator
11/12/2019 12:05:19

Thanks for the tip John I have two on order


09/12/2019 09:51:26

Thanks Brian I forgot about them they do good stuff so two ordered via number one son as Christmas/birthday presents


09/12/2019 08:37:14

Hi can anyone point me to a supplier of clutch type lubricators, I've tried all the usual suppliers:; Blackgates, MaccModels, Polly and they only do the ratchet type although they will supply the clutches to fit in your own lubricators, but I want to short cut the process and by a finished lubricator.


Thread: Potty:- Helping Dad Grasshopper Engine
29/11/2019 17:43:18

Hi Jim

Thanks for your interest in my grasshopper engine design unfortunately despite encouraging noises from editing team I don’t think it will be published in the near future you could try giving the Ed a gentle push


10/11/2019 08:16:08

Yes I made a 100mm one this makes the calculation easy my version is different in that it has a swivel base, this also makes it easy to set up. I submitted an article to ME workshop but as yet its not been published if any one would like a set of drawings just PM me.





Thread: South Cheshire Model Engineering Society Annual Gala
05/09/2019 09:31:09

I’ll ask tomorrow Dek if it’s ok I can give you a lift


04/09/2019 09:18:54

poster v2.jpg

South Cheshire Model Engineering Society will be holding its annual Gala on Saturday 7th Sept 11:00am - 4:00pm Steam Train Rides, Exhibition of model Refreshments.

Thread: Making High Speed Steel Injector D Bits
18/06/2019 08:05:22

Thanks for your valuable input again Juilian

When I attempted to make a 12oz injector I wondered about the need for the 6 deg reamer for the delivery cone at some point in the future I'll have another go at making a 12 oz. For my first attempt I used the 24 oz basic cone sizes one of the difficulties with this was the hole depths its bad enough drilling a No 70 hole but when your trying to drill it nearly 1/2" deep is a bit tacking. Especially with dodgy quality drills I got some of flea bay supposedly German Manufacture of a make I'd not heard of 50% were next to useless with the point not ground correctly or not at all. When I worked for a living we use to swear by Titex small drills but these are eye watering expensive unless I can drop on a good supply of cheaper drill I'm going to have to bite the bullet and buy some.

For my next 12oz attempt I'm going to reduce the length of the cones to give myself a fighting chance of drilling the holes.

I would agree with Julian and Nigel its not a Black Art its just a matter of gaining an understanding of how they work and how to make them (I have a good coach) and this only comes with having a go, being patient and persistent learning by your mistakes and not giving up and taking the easy rout and resorting to cheque book engineering and buying one.

As an aside I've just tested the second vertical injector to my own design, and it worked though we did have to reseat the ball to get it to work. The test boiler is electrically heated so when we got it to 90psi we turned the electric off started the injector and watched the pressure drop as it put water into the boiler:- when it got to about 55 psi it started to splutter (stop and start) but it didn't stop completely until it got to 45 psi.

The design for this vertical injector is very much in the development stage I want to try refine it further.


17/06/2019 08:04:29

I'm pleased you like my grinder set up Nigel.

I have covered the slide ways some time back, I used the lorry curtain side material its ideal for the job.

I've only ever used it for cutter grinding but yes it would be possible to adapt it for surface/cylindrical grinding but just how accurate it would be would be the ?.

The injectors I make have quite a large delivery rate about 24oz. I run my simplex with one of them along with the axle pump the axle pump does the job of a small injector. I'm planning on using two injectors on the Crab I'm building along the lines of Dags suggestion one large one small. I've tried making a 12oz delivery injector using the sizes from Dags book but failed miserably.

I think I failed on a number of accounts, I was far from happy with the reduced size turned D bits, and I used the body and basic cone sizes as for the 24oz injectors and just changed the hole sizes. At some point in the future I will have another go with ground D bits with a smaller body and cones.



16/06/2019 19:01:22

Sorry if I gave the wrong impression. But I had a few frustrating days trying to get a lbsc injector working it was only when a friend pointed me in the right direction and gave me some coaching on the subtleties involved did I have some success, there are a number of not obvious features that are critical to function and the only place I’ve seen them dealt with is in Dags book


16/06/2019 08:33:21
Posted by Boiler Bri on 16/06/2019 08:09:01:

Thats great. I am just in the process of drawing up LBSC injectors to have a bash at making some. I was going to ask how to make the reamers.

They will be slightly hollow grinding them on the face of the wheel. They look like they will be sharp.



If your going to try and make an LBSC injector "good luck", I've no doubts that his worked but many have tried and many failed the trouble is that LBSC doesn't tell you exactly how to make them he has had many rants at people who couldn't make them:- all he said if you make them EXACTLY to the drawing and they will work but he doesn't say how to achieve this. Also he published quite a few different design that suggests that he was doing quite a bit of development work.

Can I suggest that you get a copy of Dag Browns Book "Miniature Injectors Inside and Out" its very comprehensive and is a good starting point for any one wanting to make there own injectors, but I find some of Dags, methods long winded and the bodies of his injectors are far to complicated there are other simpler designs around.

These are mine


and a vertical one



16/06/2019 08:06:10
Posted by Harry Wilkes on 15/06/2019 10:58:02:

Interesting rig you have there yes


Thanks for your interest Harry

Here are some more pictures of the set up.




The grinder it self was quite easy to put together Its just a Myford vertical slide with an ordinary bench grinder mounted on it you have to remove the base of the grinder and do a little rewiring to mount it securely and a X,Y table mine came from axminster but there are plenty of other suppliers of these tables out there. and it all mounted on a bit of ally plate but a friend made one and mounted his on a kitchen work top off cut.

As well as the end mill grinding jig I've also made jig for sharpening slitling saw and lathe tools.

Its far easier to put together than a Quorn cutter grinder or one of the other home built cutter grinders designs around.


15/06/2019 09:53:52

Its usual to make Injector D bits from silver steel by machining the taper on the lathe then sectioning with a file or mill then to heat treat, whilst this method can produce a perfectly functional D bit there are a number of draw backs:- you need a razor sharp turning tool to machine the taper to avoid distortion like wise when it comes to sectioning and heat treating can be a bit hit and miss.

This got me to wondering if it was possible to make some D bits from High Speed Tool Steel in a home workshop.

The starting point was to buy some 5mm Dia HSS tool blanks these were 4" long so I cut them in half then using the hand drill I roughed them out on the bench grinder.


I have a "home Brew" cutter grinder that I put together using commercially avaiable parts:- Grinder, an X,Y Table and a Myford vertical Milling attachment


The first job was to dress the wheel up square to the table, using a diamond.

I have a home made grinding attachment that uses a Er32 collet and an index plate for sharpening end mills by taking the pin out of the index plate I could rotate it by hand. The attachment was set over at the required angle


And the D bit ground to the required angle


To section the bits I first roughed them out on the bench grinder then with a grinding point in the mill set a max speed the Bits were sectioned off to size



I've just used them to make some injector cones and they cut far better than the silver steel bits and it looks like they are keeping their edge well.


Edited By Stewart Hart on 15/06/2019 10:04:07

Thread: Vertical Injectors
01/06/2019 19:05:47

Thanks for your interest David

I’ve been slowly moving Towards a firmer design and a more robust system of manufacture when I get there I’ll write an article for the magazine



Edited By Stewart Hart on 01/06/2019 19:07:08

Thread: Small air compressor sufficient to run a Potty Mill
01/06/2019 06:49:34
Posted by John Duncker 1 on 31/05/2019 20:50:07:

I need a small air compressor sufficient to run a Potty Mill 16 mm bore 32 mm stroke

Will this sort of thing do do ?


I suspect not.

I guess I can use it to build up some pressure in an air reservoir [ plastic coke bottle ] then use that.

Space and weight matters as my workshop is a tiny cubbyhole on a boat.

Yes it should I've run my engine on one. also used it to run my twin cylinder over crank engine that has a far greater cylinder volume.

Try inflating a child frog hopper bouncer and couple it up:- to increase pressure just get some one to sit on it smiley


Thread: Water Tank for Wagons
31/05/2019 08:22:16

Some time back I bought a part finished Tender it was my intention to use it with the Crab Loco I'm building but when I got round to looking at it I realised that it wouldn't be suitable, so it sat under the bench. Then last winter as a change from working on the Crab I decided to convert it to a water/coal wagon for my Simplex Loco. The basic conversion went well, but I really struggled to convert the brass sides into a leak proof water tank it must have more solder than brass. This got me to think if any one has converted a plastic container or made a plastic tank any comment would be appreciated.

Any way this is my Water/Coal Wagon.



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

Support Our Partners
Eccentric July 5 2018
Eccentric Engineering
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