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: Making High Speed Steel Injector D Bits|
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.
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.
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
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
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.
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|
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|
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
|Thread: Water Tank for Wagons|
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.
|Thread: Potty Mill engine materials list wanted|
I never compiled a material list for this engine. The material is mainly low cost aluminium and steel standard stock sizes:- though I've used metric sizes it you will be no problem using the nearest imperial size.
There have been a great number of these engines built to my plans, the drawing in Thors link were done as a drawing exercise that are over complicated, if you want a set of my drawing just send me a PM with your email address and I'll mail them you.
|Thread: Help a beautiful lady|
Thank you for your replies I knew I would get some good replies from the ME community, we'll follow up your suggestion today
This is nothing to do with Model Engineering but this is the only way I could think of of starting a UK wide search. The problem is my 93 year old mother in-law has exstreamly marrow feat size AAA and she is desperate to buy some new shoes before the ones she has fall to bits. We took her to her usual shoe shop in North Wales on Saturday only to find that the shop had shut down and we can’t find any other shop who stock AAA width shoes so does anyone out there know of any specialist shoe shop who stocks them. You would make a lovely lady happy
|Thread: Adjustable workshop perching stool|
This is the thread you want posted by a guy who goes by the name of "Ye-ole steam dude"
I got my plans from the same place, but I made mine from 20mm box section steel. I wanted a project to practice my welding on, my biggest mistake was with my first weld it took me by suprise and I burnt through the box section the other were ok and they got neater the more I did.
No Jim its not the old throne its off an kitchen stool I was using in the workshop, the drawing calls for a 10" diameter seat the kitchen stool was 12" so I just cut one edge of it off to make it 10".
Waste not won't not
If I have to stand at the bench for any length of time my back start to ache I have an old kitchen stool but its height is far from ideal particularly if a move it around bench to lathe or mill or loco assembly table. Then I saw this design on one of the other forums I frequent, the seat has a clever self clamping device to adjust all you do is take your weight off it and move it to the height you want the sitters own weight provides the clamping force.
Before we have any wise cracks about the side ways photos I did turn the the correct way round but this hosting just won't load then the correct way round any suggestion why this is.
Edited By Neil Wyatt on 13/05/2019 15:10:47
|Thread: Vertical Injectors|
|Thread: LBSC Ayesha in Steam|
South Cheshire MES hosted the 2 1/2" Gauge Society at there track on 5th May and had LBSC Original Ayesha locomotive in steam.
Enjoy the video we certainly enjoyed the day
|Thread: 2 1/2" Gauge Society Event at South Cheshire MES|
I hope you made it to the event
For those who missed it this is the Video I took it features LBSC Ayesha running on steam no mean feat for a loco built about 1920
South Cheshire Model Engineering Society will be hosting the 2 1/2" Gauge society this Sunday 5th May. Who will be bringing along LBSC locomotive AYESHA this Locomotive is famous for the "Battle of the Boilers" held in 1922:- this battle raged between Henry Greenly, Curly Lawrence and others in the Model Engineering press for many months until they decided to settle the argument by holding and efficiency competition where Curly pitted the performance of AYESHA against other locomotives the result was a close run thing and was far from conclusive, so the controversy continued. AYESHA was at last years event and managed a sedate lap of our track which is remarkable for an 90 year old locomotive.
Visitors will be most welcome.
Our Track is Rear of Peacock Hotel, Crewe Road Nantwich Cw5 6NE www.southcheshiremes.com
|Thread: Starrett type clamps|
Thanks for your comments and interest chaps
They wern't that dificult to make.
To make the bodies a matching pair I simply bolted them together and machined them as one. I was unsure just how much the cold rolled bar would distort due to releasing the stresses:- so I roughed them out first and let them stand for a couple of days then I skimmed the base and top flat this took out the distortion.
Finishing off body
The jaws couidn't have been easier you just have to drill the M3 hole for the keep first before drilling 6.5 using the self centerng four jaw chuck
I used a M8 coach bolt to fabricate the screw and welded the knurled head in place.
Total material cost about £6 and not much more than a days job
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