Has anybody built Beng’s Danni Steam engine.

[Perko7Participant @perko7]

Brian, i purchased one of those 'inexpensive' vertical slides from Hare & Forbes and found that the square nuts used in the T-slots would strip if the clamp screws were tightened up enough to firmly hold the workpiece. I made up some proper T-nuts out of square steel strip which gave me more than twice the thread depth and no more problems.

[HopperParticipant @hopper]

Hi Brian, yes, something like a 12mm diameter end mill should do the job for you. Spin it at about 400 to 800rpm and see how you go.

[Lawrie BradlyParticipant @lawriebradly72996]

Hi Brian, Yeah I reckon a 12mm cutter is what I'll use. My approach is to take cuts of only about 0.5mm to 1.0mm deep at a time – nice and slow. That way you don't get a lot of stress and vibration – and for me 'time isn't of the essence.' Regards, Lawrie

[Brian JohnParticipant @brianjohn93961]

Geoff : any chance of a photo of the T nuts you made ? How much thread have you put on them ?

[Brian JohnParticipant @brianjohn93961]

Another holdup : I have spent the last two weeks moving house (wife's idea) and cleaning the old apartment to vacate standards. The new workshop has much more room than the old living room ; lots of cupboards and storage space.

The drill press seems a bit wobbly for some reason and that will have to be looked at. The lathe bench is firm and stable. I have spent the morning rereading this thread and working out where I am at. I don't even remember making some of these parts !

For Australian residents : Now that Miniature Steam are no longer selling bar stock, who are you buying your brass and gunmetal bronze from ? What is the smallest diameter gunmetal bronze that you can readily buy ?

 

 

Edited By Brian John on 25/07/2017 04:47:36

Edited By Brian John on 25/07/2017 04:50:50

[HopperParticipant @hopper]

Brian, the new workshop looks good. I buy my bronze and brass from Allied Bearings usually. Not sure how small they go down.

[Brian JohnParticipant @brianjohn93961]

Thanks Peter, I was not aware that Allied Bearings sold that. I called them just now and they have some 1/2'' gunmetal bronze in stock which seems to be the smallest available. He said they do not keep brass and but they can get it in on special order. Is that what you ask them to do ?

[Brian JohnParticipant @brianjohn93961]

The vertical mill slide arrived today and I have been watching some youtube videos on milling in the lathe. Some people seem to think that holding the milling bit directly in the lathe chuck is a bad idea and it should be held in a collet to avoid damaging the chuck. Is this correct ? What type of collet should be used ?

[JasonBModerator @jasonb]

It won't damage the chuck, some say a 3-jaw won't hold the cutter as firmly as a collet but if you just take light cuts then it will be fine in the 3 jaw. That Minnie traction engine in my avitar had all the milling done on the lathe with cutters held in the 3-jaw

[Brian JohnParticipant @brianjohn93961]

Trying to fit the vertical mill slide. I removed the top slide from my lathe. It looks like the supplied steel bush fits in the hole on the mill slide then using a washer and a M6 X 44mm socket cap it will be screwed onto the cross slide. Unfortunately I do not have an M6 x 44mm socket cap or an M6 X44mm bolt of any type so things will have to wait until I source that.

Am I on the right track here ?

Sorry : I should have taken a photo showing the hole in the mill slide which takes the bush.

Edited By Brian John on 29/07/2017 10:09:33

Edited By Brian John on 29/07/2017 10:10:39

[JasonBModerator @jasonb]

To get you going why not use the long stud that is laying next to your tool post and a nut, may need a bit of scrap tube or a couple of larger nuts to use as spacers if the thread is too short.

Is there just one hole in the bottom of the slide casting?

[Brian JohnParticipant @brianjohn93961]

Here it is with and without the bush :

Why did they make the bush so long ?

Edited By Brian John on 29/07/2017 10:46:51

[JasonBModerator @jasonb]

by raising it up you will get more swing on an allen key allowing for the length of the short side of the key.

I'd definately try it using teh stud from teh toolpost and a packer if needed.

[Brian JohnParticipant @brianjohn93961]

Wonder of wonders : Bunnings had some M6 X 45mm socket caps on the shelf. I used two washers to get a good fit and it looks like it is ready to use.

What sort of cuts should I be taking with equipment like this : 0.5mm or 0.25mm at a time ?

Do I lock the carriage in place like I would with parting off and remove Xmm from the whole face before unlocking and advancing the carriage to remove another Xmm ?

Or do I remove all the required 4mm from one part of the cylinder and then raise the mill slide to remove the next section.

These may seem like dumb questions but I have not done this before and I do not want to race in and break something.

Edited By Brian John on 30/07/2017 06:37:20

[Thor 🇳🇴Participant @thor]

Hi Brian,

If you can, lock the parts that don't move while taking a milling cut. Since I don't know your lathe my advice is to start with a light cut and see how your equipment copes, you will soon get the hang of it.Take it a bit slow with light cuts to begin with and increase dept of cut and see how the lathe performs. Good luck.

Thor

[JasonBModerator @jasonb]

Yes lock the carrage and vertical slide if it has a lock screw. Start with light cuts and see how the machine handles them, increase if it sounds OK.

I think I would take several cuts at each height setting stopping just short (0.25mm) of finished size. Then take a final cut with the carrage locked and just moving the vert slide about 1/3rd of the cutters dia until you have milled the whole face.

[Brian JohnParticipant @brianjohn93961]

Please check out how I have mounted the cylinder in the mill slide and comment if this is correct. I have removed 1.0mm from one section taking 0.25mm at a time. I am using about 600 RPM on the lathe ; it seems to be working.

[Lawrie BradlyParticipant @lawriebradly72996]

Brian, Success at last. How anyone at Bengs could suggest that 'the flat' could be achieved with a file is beyond me. (Though apparently apprentices at Rolls Royce in the early 20th century had to be able to file a one inch square on a round shaft, to earn their papers.) Anyway, with the vertical slide, for you and the Danni engine hopefully it'll be all plain sailing from here on in!

In the meantime I've been trying to post a photo of my progress making a scratch-built twin cylinder version of the Danni, alongside the single cylinder kit – which still has a long way to go – but I can't access my photo album when I try to post it to the forum. I might have to ask my son how to do it.

[Brian JohnParticipant @brianjohn93961]

Lawrie : I wonder how long it would take to file the flat by hand ?

It is progressing slowly : the only problem I am having at the moment is the top of the cylinder is pulling slightly away from the mill slide towards the cutter (about 0.5mm). I will experiment tomorrow with better mounting methods than the brass bars I am using now.

''A one inch square on a round shaft'' : Was that brass or steel ? Did anybody on this forum have to do that in their apprenticeship ?

[richardandtracyParticipant @richardandtracy]

A colleague took an apprenticeship where they had to make a 25mm square on a round shaft. Most assumed it was to be filed. He couldn't be bothered with the effort and milled it. On the basis that only someone determined to go out of business would file it in this day and age, and being a bit portly, it was also too much like hard work. He got full marks for the assignment, and the maximum for anyone filing it was 50%. The deduction was for lack of initiative.

Have you noticed, frequently the best machinists are the laziest people? They find the quickest and least effort way to do things. A bit of thinking can save lots of effort.

Regards

Richard.

[roy entwistleParticipant @royentwistle24699]

'A one inch square on a round shaft'' : Was that brass or steel ? Did anybody on this forum have to do that in their apprenticeship ?

It would have been steel. the majority of engineering firms in the UK would have the apprentices doing something similar. We had to cut a square hole in 1/2 " plate then ( drilled then chiselled and filed square ) then had to file a square on a round bar to fit. In those days a fitter was expected to be able to use a chisel and a file correctly

Roy

Edited By roy entwistle on 30/07/2017 11:40:00

Edited By roy entwistle on 30/07/2017 11:44:14

[Lawrie BradlyParticipant @lawriebradly72996]

Hi Brian, I reckon I would try to grip the ends of the cylinder with not quite parallel brass jaws – so the outside of the jaw grips (with a bit of clearance) towards the slide. Sort of clamping the work piece against the slide. It would involve making a shallow angle (a couple of degrees) chamfer on the brass jaws. But then, what would I know. My only qualifications are in economics!

[Lawrie BradlyParticipant @lawriebradly72996]

I think the expression I might be looking for is "pulling it into a taper"!

[JasonBModerator @jasonb]

It is only a face to be soldered so not that hard to file to a suitable flatness, the solder will take up any slight variations.

Brian I would take the bottom packing out and move the lower jaw up if needed. You may also need to tap the cylinder back against the slide as you tighten up the screws

[Brian JohnParticipant @brianjohn93961]

I was worried that if I took the bottom packing out then the steel jaws of the vice might leave some sort of mark or indentation on the brass. I am going to try a larger piece of thick, flat aluminium for both top and bottom if I can find something suitable from NORWELD tomorrow.

Edited By Brian John on 30/07/2017 14:01:30

[Author]

Posts