Member postings for Ramon Wilson

???

How long is it in comparison to the shaft ? - if its well over long then any error will increase if you need to bring the tailstock closer to the chuck to machine the shaft

Ideally you want the tailstock quill extended an inch or so when you take a test cut with the tailstock in the approximate position you are going to use to turn the shaft. That way you don't move the tailstock only the quill to get the shaft in and out after you have set your tailstock.

I should have said - lock the quill before taking the test and adjusting making sure you do the same when turning the shaft.

Make yourself a between centres test bar Doc -

Take a piece of mild steel about 1/2 to 5/8 diameter and turn about an inch in at each end to about 3/8 to 1/2 diameter. Centre deeply each end as you do it. Set between centres and turn the middle part to roughly the same depth - finish is totally unimportant leaving portions of the full diameter about 3/4 long at each end.

Now take a very fine cut across the large diameter section nearest the tailstock and not changing the cross slide setting move the carriage to the section near the chuck and repeat. Try to get as a good a finish as possible - you only need to take a few thou off.

Measure each end and adjust the tailstock accordingly to any difference found - put a clock on the tailstock and adjust to half the difference - take another test cut and measure again. Unlikely you'll get it perfect but within a thou is good over 8 inches or so. Bear in mind that depending on the state of the lathe that's only as accurate as the bed is in shape so make your test bar to encompass the crankshaft length and try not to move the tailstock position till the job is done. By doing this you don't have to cut that portion between the measuring spots.

When turning the shaft work in from each end of the shaft from the tailstock end - reversing the shaft to do so. This will minimise any errors and be as accurate as your lathe and your measuring will allow

If you can't quite picture what I mean I'll take a picture of the one I made years ago - still in use on the original larger diameters.

Hope that helps

Edited By Ramon Wilson on 21/07/2022 16:01:54

Well, as said so long before - "Listen to all, make your own mind up and go for what you consider best"

Jason has built some fine engines and his skill is not in doubt. Often, however, I see things from a different perspective and try to convey that - not in opposition or disagreement but from an ease of machining perspective to arrive at the best accurate result with limited kit.

In an ideal world the shaft would be drawn with dimensions clearly toleranced as would the components to fit it. Each tolerance, if worked within, would ensure the correct type of fit. As we are not in an ideal world so compromises have to be made.

So - stock material - in my book all you can do is measure it and make everything that goes on it to suit - Flywheel, bearings, eccentrics and cranks - we haven't even got to fitting them yet. Stock material rarely has a surface finish you can accept for such a fit as a running bearing. Okay, maybe, for line shafting but you are making a precision item. Each bore has different requirements so all need separately required measurement. If however, all are bored beforehand - even if slightly different in tolerance, then the shaft can be made to fit each part - much easier to do with the shaft off the lathe than trying to insert the shaft in a small item in the lathe (flywheel excepted) To use stock material as a plug gauge in order to turn a fit suitable for a running bearing is not, in my opinion, a way to go about obtaining such a fit.

So, in my simplistic approach, the parts require a uniform bore (of varying diameters if desired) and the shaft is turned to suit - easily measured for certain - and the shaft brought to size to suit each component.

The book text, you say, confirms what I'm advocating - turning the shaft from larger material.

There you go then Doc - paying money and choosing is your option

Best - R

Edited By Ramon Wilson on 21/07/2022 14:03:28

Unless it's Precision Ground Mild Steel bar Jason no stock material would really be suitable due to the reason you state - likely to be undersize. I don't know what Stuart supply but didn't Doc say he only bought castings?

Short of using PGMS two thou down is not an ideal starting place unless as you say the bearing is turned to suit and not reamed to stock size - that would be a rattle fit as far as a main bearing tolerance is concerned let alone the fact that basic stock material is not truly round either - even silver steel

It's 'horses for courses' of course but I would have assumed anyone making an engine of this nature would make the bearings and shaft a very good running fit to each other.

If I were to make another of this design I would certainly make the shaft with stepped diameters for ease of assembly. ie no spoiling of the running surfaces as the fly wheel and eccentrics are positioned. Once the cranks go on of course, that's it.

One thing I learnt early on was it makes life much easier if, for most part, you put the horse in front of the cart

PS PGMS incidentally is a lovely material to turn further if required - probably close to EN1a free cutting. It turns and screw cuts extremely well. I think EKP offers it as well as M-Metals

Edited By Ramon Wilson on 21/07/2022 12:54:27

Well each to his own Doc but it should be quick to realise that it is much easier to make the bearings and other bores first - preferably with standard sized holes and then make the shaft to fit - as said, unlike a chuck or even a collett if done between centres it can be removed without fear of movement and the shaft parts are much easier measured than bores - ie you'd need to carefully measure the bores to the correct size to suit the shaft and try the shaft in the part rather than the other way round - apart from the flywheel and unless there's no option it's not the ideal way to go about this task.

Just 'polishing' the shaft until the parts slip on is much the easier way.

Here's a pic of the tapered tool. It's one that gets probably more use than any other from a finishing aspect - works in either direction and is ideal for turning those unimportant radii by eye such as transition on crankshafts etc

You have to bear in mind Doc that my advice comes from a time when this way of work was standard in a jobbing shop - get the job done but accurately and at low cost (ie time) with what you had at your disposal bearing in mind the machinery available - no CNC in those days and carbides used only for roughing. In forty odd years of machining I only saw a solid carbide endmill in my last three years - and they were only used on the new Haas machining centre.

I always try to offer my advice well aware of the limitations of an ML7 and the issues you have with your mill

Personally I would use HSS to obtain a fine and accurate diameter. Yes it can be done with carbide but you need to scrape that last few thou to a fine surface and maintain diameter. Much easier to do with a freshly ground piece of HSS

A round nosed taper tool will cut the radius at any increase in diameters as well as providing the fine control

Here's mine in use on the Corliss shaft (note the shaft is pre machined and is set between centres for finish turning - turning the shaft around to finish each end at the tailstock end)

Using HSS gives a finish that allows a fine polish with wet and dry paper to bring to an almost ground like appearance without losing dimension to any great amount.

Jason as a confirmed carbide devotee will have other ideas but that's what I would do.

What material do you intend to use - EN1a free cutting steel is the best option when running on bronze or brass - a very good combination. The last material I would turn too would be silver steel. Not a good choice in my opinion for this specific item.

Just another thought - it should go without saying but you need to have your bearings finished (but not slit at this stage) to use as gauges and like wise the flywheel bore - much easier to do than the other way round. By machining between centres you can safely remove the shaft to check the fits  - off the lathe

Edited By Ramon Wilson on 21/07/2022 08:13:00

Edited By Ramon Wilson on 21/07/2022 08:17:36

Yes, I can confirm one size smaller BA nuts are available from EKP plus several others and they are used constantly throughout my builds. On the smaller sizes I sometimes tap the next smaller nuts out too ie 10 BA Nuts with 8BA thread.

So far have not used any metric.

In my opinion the standard size nut (and head) and the odd BA sizes as specified by Stuarts are way overscale and require a rethink on all uses - for a more scale effect.

All the 1BA hold down nuts on the Corliss engine were made from scratch to achieve this so that's another alternative

That's a great result indeed for a first engine Mark - you should justifiably be pleased with your endeavours.

Always great to see something you've made burst into life and run and yours looks to be running well

'Congratulations' are well deserved.

Fired with such a good result what do you have in mind next?

Regards - 'Tug'

NIce work Jason and a neat result. - that's exactly how I did the Corliss caps BTW - series of fine flats before filing

Looks like you are spoilt for choice now Doc

Well me too Peter - The choice to keep life as simple as possible erodes us daily. A couple of years back - local Nationwide branch - branch assistant - "We don't appear to have details of your mobile phone number" Er we don't actually have one and don't particularly want one either. "Well you need to get one you know you will need one before too long"

No still haven't got to grips with that one.

Like you, I approach my eighties - I'm glad I've lived my life when I did and have had a good one but I really am glad I'm not setting out as a young man at this point in time.

Time - now theres a provocative word - to some it can be wasted at a whim but at our age every minute is precious. Giving ones time becomes ever more a consideration when one considers how diminishing on a daily basis it is and especially when it's obvious it's not appreciated for what it is to us (at our age)

As I often say 'I'm getting old - and I don't bloody like it!'

My sympathies all round, I certainly empathise with you

Stay well, Tug

Totally 100% behind this advise. Especially on a two bed engine. Build, and paint, if you can, as you go so that at each stage the engine is fitted and running as it will finish. Building it to a running fit then stripping it down for painting nearly always results in misalignment issues - slight I agree but can be troublesome

When the Waller was built I did this on a 'building plinth', a direct dimensional copy of which I created as a base and plinth for the final mounting. The engine ran lovely until after the strip down for painting and reassembly when issues arose and the most annoying knock was prevalent that took quite some time to trace and fix.

Just another comment

I don't know what else I can say here Doc but ...

Twin Victoria, Waller engine, Double Diagonal engine, McOnie Oscillating Engine, Stuart Double Ten rebuild, Throp Corliss engine - have all had bearings done as described above. They are two part, as Jason shows too, the pedestal and the bearing. Make the pedestal first then make the bearings to fit the pedestal

Use the four jaw by all means but don't be surprised if a, you distort something or b, they are not both the same. Personally I would not for the reason you state too - the front face may be in line but what about the back inside the chuck.

Just trying to guide you on a path to ensure minimum time and good success.

When I did the bearing caps for the Corliss engine I just filed them from rectangular blanks of cast iron after putting in the lower recess and drilling the holes for the bosses. The plinth that the oil box sits on was a separate insert JB Welded in. There's really no need to complicate things - as Jason alludes, it's a casting you want to represent not a precisely machined component.

Here's a different approach on the marine engine build

Rectangular slots cut in line in the bed plate

Split bearings and caps

As said previously - it's much easier to shim a square bearing into line than a round one - vertically or laterally. Though ideally this should not be a guiding principle - aiming to get it right is - just that if it does need a tweak then you have the means. Relying on movement of the pedestals will work but is not an ideal way to approach matters in my book especially if stripping down in the future.

I hope this helps - obviously having two sources of help is confusing at times but I really cant see how I can help you further on this particular aspect of the build.

Regards for now - Ramon

Ah! you mean like this Jason The oil cup holes on these two caps are just a push fit for the oilers but yes they are usually threaded

Another benefit of square bearing blocks is that they are easily shimmed (out of sight) to fine tune the crankshaft level (important) and, of course, they don't need extra work to prevent them rotating in the housing

When it comes to milling the feet that's where a home radiused cutter (done on an offhand grinder) gets pressed into use.

Wouldn't see that LG2 bronze as a machining problem - that would be a good choice with a turned steel shaft

but then we're all different

Posted by Dr_GMJN on 15/07/2022 08:13:44:

Thanks both for the info. As I mentioned, I’d like to stick to the look of the article model, and keep at least some of the bearing castings (ie the uppers), so ideally I’d have circular split bosses rather than square.

Could you outline how to make these, is it a question of turning oversized flanged bushes, splitting them, then JBWelding them into the bearing castings, then re-joining and boring?

Ramon - I don’t have a boring head for the mill, but you’re saying the housings aren’t strong enough to be clamped in the 4-jaw chuck? I machined the 10V big end in the chuck, but it was a bit smaller/stiffer I guess.

Cheers.

Hi Doc,

No, I'm not saying they can't be done using a four jaw chuck just that the material is easy to distort. If you apply sufficient pressure to hold the part for boring there is a good possibility the pressure of the jaws distorting the thinner walls left. My reasoning is simple, why go there in the first place and risk it - if you machine everything to the bore then that potential is irrelevant.

Doing circular bearings is exactly the same - solder two pieces together and hold on a mandrel - the difficulty is finding the exact centre line from semi circular pieces (if you go that way - just easier and far more accurate to make them square in the first place).

Again, not saying it can't be done just much easier to get the right end result with square bearings which as said are far more true to prototype than circular - on main bearings that is.

This is a pretty simple part to manufacture from scratch - I can understand the desire to use the original castings but to try to compromise is not ideal - as ever "one pays one's money" etc

I have plenty of bronze so can send you some with the form tools - just let me know the overall dimensions you need.

I would agree with you to leave the bed plates as is now but go ahead with scratch built bearing housings and bearings.

I have found the form tools - two pieces of 1/4 square HSS - I note the form was ground in with a true radius so this dates my build around 1983/4 as they were done on a J&S grinder with 'Optidress' wheel dressing/shaping kit. Must have been one of my first 'homers' at a company I joined in 84 !!

Making external form tools from HSS is usually a carefully approached attempt on an offhand grinder - use those small bits I sent you so there's not so much grinding. Internal forms (in HSS) are a different matter without recourse to some special kit so it's then down to creating the shape in tool steel - usually silver steel or gauge-plate for instance - my machining/filing before heat treating. I always quench in oil and if it's a small tool for just doing half a dozen oil cups for instance very rarely bother to temper but keep the maximum hardness. Sharpening is best carried out using a diamond file - hand grinding on the offhand grinder will quickly lose the hardness without extreme care.

Have to go now - breakfast calls.

PS PM your address

Edited By Ramon Wilson on 15/07/2022 07:47:35

Hi again Doc,

I have just created a new album with a series of images for making split bearings in my albums but will post a few? of the basic ones on here as it's relevant to your question - hope that's okay.

You can make split circular bearings but these would not be true to prototype on the size of bearing you wish to represent. Split rectangular bearings are not exactly scale either but are much closer!

Once you have established the dimension you require cut and mill two blocks to overall dimension plus 1mm and long enough to cut into two to give top and bottom pieces

Cut apart and face the sawn edges but do not worry about exact dimension at this stage. Make all blocks the same or at least the two lower blocks and note down the dimension from the split face to the lower surface . Then tin both parts on the split line face ready to solder together.

The parts need to be held together but not clamped. I use a spring clamp made from a piece of 12 swg piano wire. Lay the parts on something flat that will not absorb too much heat and make sure the flat plane is uniform. Heat until you see the solder line go bright and drop a small amount of solder on to be certain.

Clean the blocks of flux then mill the outsides true except the lower face. From this you know exactly where the split line is located so set in the mill and drill bore etc for the crankshaft.

Mill the outsides dimensions to the bore so they fit the pedestals

Then finally make up a simple expanding mandrel to hold them for facing the outsides. This is quite a small one as these bearings were for the layshaft on the Waller valve gear but the principle is the same

As said there are more images in the album which should be self explanatory but if you're not sure about something just say.

Hope that helps - R

Edited By Ramon Wilson on 14/07/2022 20:58:37

Ali will be just fine Doc but some would say it's not a good combination with brass. Personally I'd go with it.

Re making the 'brasses' - I have several images of the process so will post them a bit later for you - just been called for my evening meal - daren't be late for that eh!

Back in a bit

Well, as a Lowestoft lad of 77 years MAX-T is a new one on me Peter. Certainly not aware of anyone in our area supplying small tooling such as you require. That doesn't mean there isn't, just not aware of anything.

I have some pretty crudely ground bits of HSS that do the business - ha! - on another thread I was mentioning working at a jobbing shop - still have the tool I ground up to do internal o ring grooves on a regular job we had.

I took the time to make the George Thomas design boring tool holder which was well worth doing but most of the time it's my old cobbled together 'bits' that see the action (not that there's a lot of that these days!)

You can make very nice small boring bars from old endmills/slot drills - just grind it all away save one tooth

Hope you are keeping well

Tug

Far too long ago to think about I worked in a jobbing machine shop where we did a fair amount of work for two local blow moulding factories. One of the items we did an awful lot of were 'blow pins'. Turned from stainless in sets of three they had a uniform shaped threaded top end and a long varying much smaller diameter lower end to suit the particular moulding (bottles) and varying lengths about 150-170mm long

They had a hole drilled right through which was done from both ends. Agreed, it only had to pass air which meant accuracy and perfect alignment wasn't an issue and yes the drill did wander at times but more often or not the holes would allow the drill to be pushed right through after drilling. If I recall correctly the largest drill was 5mm diameter and with some 4 and occasionally 3mm the latter a particularly fraught time. I well remember doing one when the drill wandered enough it broke through the side of the pin which was about 7-8mm diameter.

Done by hand on a Colchester 2000 lathe only basic HSS jobbers drills were used - standard and long series so nothing special and the drilling began with a short series drill to get a good concentric start.

As has been said pecking and frequent withdrawal with plenty of coolant was essential to aid swarf removal - a tiring exercise when the tailstock was constantly being moved and several batches were sitting there to be done.

My, that was along time ago

Tug

Edited By Ramon Wilson on 14/07/2022 09:02:01