Member postings for Ramon Wilson

It's very easy to make an expanding mandrel to suit the job in hand from quite tiny to fairly substantial.

Best made from free cutting mild steel, they can be made from brass or ali but the latter do run a risk of the job spinning and galling making removal potentially difficult.

The mandrel is roughed to the shape shown to with .5mm on diameter, drilled and tapped for the expanding screw - I've done them from 8BA to 8mm - as an average 2BA/4mm is fine for most needs and deeply centred with a centre drill.

The screws are nominally cap heads that have been previously turned to have a 60 degree taper on them.

Remove from the lathe and cut the slots - 2 - 4 or 6 depending on size - with a hacksaw, return and clean out the thread and insert screw to just nip up. Turn the OD to suit the work , Using 60 degree as opposed to a standard countersink means a lot less torque required on the screw for a given grip and use.

This is one as shown above in use to reface a slightly misaligned surface

And here's an example of a tiny one - 8BA screw

They can be reused by careful setting in a four jaw but I prefer to recycle them down wards so each is fresh to the new job.

Yes I do have a set of arc euro ones (not the same as OP) but have never used them - Nicely finished and ground their range never has never fitted any job.

Not to take a sale away from Ketan but the cost of one would buy a fair amount of EN1a to provide a good range - just needs a little bit of time and of course there's only the need to make the one required at the time - not a 'set of them'

Hope that's of use

Tug

Edited By Ramon Wilson on 05/10/2022 10:53:18

Hi Noel, Hope you are well.

Spoken like a fine foundry man

I did consider a core but at the time the extra work to the mould to hold such far outweighed the extra work to bore the castings from each side whilst the respective faces where being machined.

I offered the above purely as an example of what I did and the end result achieved - certainly not the only way to approach this

Theres an awful lot of cats in this one for sure.

Best - Tug

Ha ha, fame at last eh Bill

Crumbs thirty years eh where's that all gone? I do hope everyone has a good day - sad not to be there but I've reached that point.....

I'm not that sure when you took that pic but things have progressed some - that M'cOnie is finished and painted, theres five more CI engines plus a sparky and of course the Corliss is finished. Shame I'm not up to bringing that but here's a pic that will have to suffice.

Again I wish you all well

Tug

Well done Jason

As one of those usual suspects this is the first year for many that I won't be attending as an exhibitor. That's something like my fourth in all the time it's been running so not a bad average. No reason other than age creeping up (well it's crept all the way I guess) I've sent Bill an email to wish all well.

Same for anyone on here who decides to give this event a look.

Have a great day if you go - as always I'm certain you won't be disappointed if it's a first time

Regards to all - Tug

When I was making parts for the Bentley rotary engine there was a need to cast the manifold elbows in aluminium.

I made a mould from two pieces of EN1a steel located by taper dowels and machined each side separately to tight tolerances to ensure alignment

I proved the mould by using lead and smoking the surfaces with a candle

Though I carried out the above fairly early on in the making it was not used 'in anger' for many years until I loaned it to someone who was also building the same engine.

He not only successfully cast sufficient elbows for himself from it but enough for my project too

As you can see the mould was quite heat stressed but unaffected by the twenty plus parts.

I have an idea that the OP wants to create a mould from a pattern similar to a silicone mould but though that will take molten lead or white metal I doubt it could withstand the temp of molten aluminium

Might be of help though

Tug

Though a completely different kettle of fish and at the other end of the spectrum to that discussed previously, take a look at this video if you are interested to see a model airplane rubber(elastic) motor being wound.

Whilst the principle is identical the torque involved is far in excess of that of any indoor motor.

https://www.youtube.com/watch?v=TFMkJ9gd6W8&t=46s

Well you are in luck Cap'n but only sort of as this is a much simpler version than you show but it will I assure you will work just as well at the kind of level you need for the rubber section involved if you make a simple torque meter to attach the rubber to when winding if measuring/gauging torque is required.

It's always best to wind off the model anyway as I'm sure you are aware.

Sue and I used this for years of indoor flying back as far as the early eighties. Unfortunately all of the indoor 'stuff' collected over that time was passed on to someone who was so-oo interested who then passed it on to someone else who was much the same - totally wasted I'm afraid.

I do have a fair amount of 36 x 2 1/32 balsa of varying grades that you are welcome too as well - not actual 'indoor' quality, never the less it was well chosen for the purpose.

If you are making your own kit for the hobby and you have not made a beam balance yet then theres one of them too sitting up the loft. I can't do it today now but I will take a pic for you next week.

There is little left of our involvement in indoor flying but what there is you are welcome too - it is extremely unlikely it will do anything but languish where it is for posterity so it would be good to see it go to someone who will get some use out of it

The Williams book was a game changer when it came out - I saw my copy quite by chance in a local book shop. I still have it but gave away the others I had - none were in the same league though.

We flew locally and occasionally at Cardington which was an awesome experience.

Best - Tug

PS Much to my wife's horror a friend and I had our lounge looking like the pic in the book when making some microfilm. A heavy odour of dope and dripping frames all round the room when she arrived home. Making it was easy enough getting it light enough was a different matter. Ah happy days

Edited By Ramon Wilson on 17/09/2022 11:35:19

I recognise that page instantly ! I still have the book which I bought must be forty years ago. I wore the print off the page at one point.

Had quite an interest in indoor at one time - only the other day I found two tapered mandrels I'd made for making rolled tail booms lurking in the back of a drawer

I can't recommend the gears but I'm pretty certain I still have one of those yellow and white commercial 10- 1 winder up the loft - if I do you are welcome to it.

What kind of models are you interested in? I was never a scale person but made many 'half scale' commercial kit models of my youth for indoors - KK Senator, Ace, Veron Sentinel etc. Also liked the Penny Plane and EZB designs too

I shall be off line for a week later today but if you PM me I'll respond as soon as I'm back on

Tug

Nothing Doc, it's always down to individual choice - just not the way I would advocate doing it based on personal experience. - and no one I should think, certainly least of all myself, considers you 'totally inept'

There always many ways to skin the proverbial cat - just some are recognised and others are not - doesn't matter which you choose if the end result justifies it as you have proved - doesn't make it right, or wrong, for that matter.

FWIW On lathe or mill I use digi calipers a lot to give me an idea of 'where I am' but always use a mic to tell me exactly.

Good luck with the rest of the shaft parts and make up

Ramon

Doc

As I said if you don't have confidence in your own ability to turn to a given diameter it's going to be a testing time at times ahead

As for the remark about being time served you've touched a raw point. I've had the pleasure to work alongside some fine time served men in my days from whom I gained much knowledge but I've also witnessed more than enough poorly skilled ones to know that a comparison cut's no ice with me.

The finest precision form grinder I knew who worked in a machine shop I ran was a press operator before he was trained in house.

Yep I've heard all the arguments about time served versus non time served but its what you put on the table at the end of the shift that counts

Jason - I would have thought it obvious by now that I've not been saying it won't work merely that its a fandangled way of going about the process of machining between centres just to get two ends identical. Besides it's a bit disingenuous to say now 'that way works best' for you after the event

Horses and water spring to mind however.

Nice result Doc but now try it the conventional way - you might surprise yourself but ditch the digi calipers for accurate measuring of parts on the lathe - use the mic at all times.

Now that has opened a real can of worms no doubt, nothing wrong with digi calipers of course but they are not the tool for the job for measuring accurately in situ even thou they do measure down to 2 tenths.

I'm off to ponder what I missed by spending my first years of 'working life' in the Army when I could have remained a low paid welder on the shipyard - not even a single bit of protective gear supplied - summer or winter and all the rust you could eat.

So what you are recommending then Jason - if I follow correctly - is

Set roughed out shaft between centres and tighten carrier in place at one end

Take first pass of 6 thou. Stop, remove component

Swap carrier to other end and, without altering the dial, repeat

Take second pass of 2 thou cut. Stop, remove component

Swap carrier to other end and, without altering the dial repeat

Take third pass of 2 thou. Stop, remove component

Swap carrier to other end and, without altering the dial repeat

Really ???

Well each to his own but that's a strange way of going about things to me. Like I said if one hasn't got the confidence to work to a thou or less off a Mic then maybe it's time to reconsider the options

Sorry - not onboard with this one at all

Doc

Why not indeed - by all means do it as you want to I'm just pointing out to you that you are over complicating things unnecessarily.

You're an academic - I've spent years on the tools - that's the difference.

It may not have registered but I'm trying to show that you really don't need to go down this route in order for accuracy but if that floats your boat then jump in.

I began my model engineering journey just like you - completely without machining knowledge and experience. The only difference was there was no Internet to guide me on a daily basis - just the monthly magazine and club meeting and the odd person - well only one actually - who really helped me. I think I may have mentioned somewhere being passed from person to person at a club meeting when I asked someone what is the best way to cut a thread on silver steel - a difficult material to do that on at the best of times. Each person just passed me on to someone else until I gave up. It would be years later that I realised that in all probability none of them actually knew!

I made an awful lot of mistakes before I gave up a lucrative career in order to machine metal for a living such was its attraction to me. Correct training was a beacon - doing it for a living was a passion. Three of the four jobs I held until retirement were jobbing workshops where time was money and mistakes were an anathema but eventually I ran two of the four machine shops.

I'm just passing on that experience - not trying to vie with Jason or force you down a route you don't want but if something's fundamentally wrong, it's wrong - I think you might agree I would not be doing you any favours by not pointing something out.

Just do it how you think best - what can go wrong, will, and if it doesn't, then it doesn't matter

Best - R

Running on air or steam Rob I would feed into the steam chest. Make sure you have means of metering and a bypass back to the reservoir though - doesn't need a lot if it's for display running only.

Are you aware of Albion Alloys copper tubes? They do some very fine bore ones suitable for plumbing oil lines but you do have to make your own unions

Tug

Hi Bob the unit you require for Tina is much smaller than the bearing block that Andrew shows.

I have soldered together all the bearing blocks for the engines I have made without any issues save one where I held it in the mill for boring/reaming with the split line across the vise, not longitudinally. The block parted with the reaming pressure.

I put a series of images in My Albums under the title 'Making Bearing Brasses - the principle is just the same for a one piece unit which the Tina has.  Maybe that's worth a look? I'm not sure how to put a link to that so just take a look at photos under the user name

Here's the last image in that album - much smaller than the Tina I would think

Hope that helps - Tug

Edited By Ramon Wilson on 08/09/2022 14:25:22

Jason, Doc,

Yes I am aware that's what is being suggested but it's not the normal way to go about things when machining between centres.

That the part is being machined between centres, yes, it can be swapped end for end between cuts without changing the settings and yes it might get you very close but if that's the only way one is able to rely on to get a repetitive dimension then I'd say maybe it's time to rethink things.

Whilst he object of turning between centres is to be able to remove and replace the component without loss of concentricity it is not to ensure radial dimension is equal both ends

Had a turner gone about it the manner you describe in the machine shops I ran I would have been seriously under impressed

The point I'm making is that is not the correct way to approach things Jason. Doc has already proved he is capable of machining to a limit so why the sudden reluctance to do the same.

If anyone using a lathe has to require doing what has been suggested then I would say they have no confidence in their ability - how would they get on if more than one part is required to be identically machined in a chuck all in one hanging.

Believe it or not many, many, of us did that on a daily basis with nothing more than a Mic and confidence in our own ability.

Adjustable dials are a huge improvement over the fixed ones so I really don't see or understand what you are so concerned about Doc

R

Edited By Ramon Wilson on 08/09/2022 14:33:47

If you do the first end in a series of cuts to get to size then do the second at the same finish setting on the dial the extra material you will be taking off in one pass will in all probability lead to a differing size. You hold the key to accuracy in your hand - your Mic - and your ability to work to the dial

As a matter of interest do you have the old fixed Myford ML7 dials or have you got the replaceable moveable type?

The former does make things a tad awkward (but a felt tip mark helps) - the latter is something that once fitted you would never change back.

You most definitely would not be changing end for end to ensure each path was identical to each cut - do one end complete then repeat the process - if you've done it once you need to be confident that you can repeat it. Doing what you suggest is not the way to go about I'm afraid.

Best - R

Doc, I'm not quite sure I follow you but once you are happy with the first end and have a reference point from the cross slide dial then I would reverse the shaft and work towards the same reference point as before but measuring as you go to be certain the cut is the same. Technically finishing at the same point on the dial should be the same but there are very small variables that can add up to it not always being so - by measuring you can see if there are any.

Don't rely totally on the dial is what I'm saying - a thou under is under size, a thou up can be rectified and it doesn't take much to be a thou out even if you are boring the parts to suit but you already know my opinions on going about it that way.

When machining to a fine tolerance once within a few thou take another pass without altering the dial and see how much more that takes off - a spring cut will usually take a very small shaving cut but you need to know how much it will remove if you do.

Best - R

Hi Dean, I'm happy to let you have them but I won't need one back though it's a nice thought. Are you still at the old 777 email addy?

I'll be in touch

Tug

Any turner worth his salt would not do the second end at the same setting without moving the tool Doc.

Both ends would be treated the same way making a note of the cross slide setting as the first end is finished and treating both independently, making careful measurement of the second end.

Pre CNC (oh! how easy it is to forget how short a time that was) it was the skill of the turner to make repetitive parts sometimes to very fine tolerances - a mic was all he had.

You are doing fine

Not to disagree with Jeff (Dayman) but making a mild steel holder to take the HSS blank makes things so much easier to maintain the angles and position the tool blank especially when roughing the tool out initially.

I finally made one after far too many scorched fingers. Just a hole big enough to take the diagonal dimension in a piece of round bar with a grub screw in the side is all that's required. Yes you do need to keep an eye on overheating but it's not a major concern with HSS as it is with home made carbon steel tools. Just a container of cold water beside the grinder is all that's required for that.

I don't think I have ever spoilt the hardness of HSS of whatever grade by grinding temperatures and grinding new tools is something I approach with a degree of 'can I get by with something else' but when needs must a holder does take the pain out of the task.

Best - Tug