Member postings for Dr_GMJN

This is the exact method I use. I’m no machinist, but can often get things centred to within half a thou in one go, mostly two though.

With two chuck keys, it’s a doddle, and with my NOGA dti stand with fine adjustment *at the base*, I actually find the process quite therapeutic (the base mounted fine adjuster makes zeroing the dti laughably easy because you don’t actually touch it or the arm, therefore there’s no spring back).

This is the exact method I use. I’m no machinist, but can often get things centred to within half a thou in one go, mostly two though.

With two chuck keys, it’s a doddle, and with my NOGA dti stand with fine adjustment *at the base*, I actually find the process quite therapeutic (the base mounted fine adjuster makes zeroing the dti laughably easy because you don’t actually touch it or the arm, therefore there’s no spring back).

Ramon - the idea was/is to build the Proncess Royal version of the Twin Victoria, pretty much to the plans from the magazine. For a second model and with my limited experience I think it's about the right amount of scale detail; it was never going to be some kind of perfect replica.

I'm all for trying to make a few minor embellishments like glass oilers etc, but I'm also fine with it being 'semi-scale', such as with the main bearings we discussed previously. I suppose that attitude might seem strange, but I think I'll be happy with it once it's complete.

The parquet thing was just a whim, and since I've not seen it before on an engine model I thought I'd have a go. If it looks a bit naff I'll bin it and try something else - probably plain wood.

BTW the very first thing I noticed at the Midlands show last Saturday was the Twin Victoria on the Stuart Moldels stand opposite the main entrance. I was surprised to see it fitted to two separate free-standing base blocks (at least I couldn't see that they were connected by anything other than the crankshaft).

Thanks guys - I'll figure something out and see what it looks like.

Roy - OK, the museum isn't a working environment, but the image Jason just posted appears to be?

End of the day it's not a scale model of a specific engine, so if steam engines can be mounted on wood - or at least within a wooden floor environment - then why not do something a bit different?

Probably, but it's a fairly large working steam engine, bolted to a wood covered floor. Good enough for me!

I was thinking of pasting brick paper around the inside of the wheel well to give a bit more interest too.

I'll mess about with some CAD of different options, and might even try a small section of parquet flooring to see how it looks with the various features like Ramon's concrete MDF bases etc.

I suppose I could get some 1" ply and make a temporary base for setting up. After all everything will need setting up again after painting. I can't finalise & paint the beds yet until I've figured out what holes will be needed for whatever cylinder drain pipework there will be.

Thanks guys.

Yes, it's just a wooden base that's got a bit more interest to it that I want. Nothing lost but some time if it looks rubbish; I'd just use a plain wooden one.

Here's one you must have missed Roy!

Object of the week - Mill Engine - Leeds Museums & Galleries

I also made the valve chest a bit wider than the valve face on mine do that the cladding fitted flush all the way around.

Thanks Ramon. I wasn’t aware you could activate PVA like that. It might be good to get the whole lot layer out properly, then iron it. I know some PVAs are re-dilutable with water (Formula 560 Canopy Glue for example), whereas the outdoor stuff is obviously permanent. I always use the former for models because it gives you chance to correct things.

I assumed the beds wouldn’t be placed on wood, I suppose it’s a bit of modeller’s license. I guess you could say the pieces might have butted up to the bed frames? I was going to use plain wood, but then when I inherited these chips I thought it would be good to use them, otherwise they will be scrap.

I’d like to make a metal jig that holds at least 10 strips at a time. Shouldn’t be too difficult.

I’m also pondering whether to make the cylinder jackets out of wood, like your marine engine. I don’t really know how to fix them though. The brass band method can to my eyes look a bit “added on later”, especially the band fasteners when they screw into the cylinder casting.

Anyhow first I need to finish the bearings, the with the shaft done I can at least say the two halves can be linked, and that will be a decent step forward.

Cheers.

Thanks Jason. From what I found online, top rails should be a minimum of 950mm above the floor, with 1000mm being common. Of course these are modern standards. Maybe there were none back when engines like this were used, and perhaps people were shorter?

Whichever scale it is, it’s only a matter of about 0.5mm difference, and since I’ve got a shed load of 4mm strips I might as well use them. I’ll have to make some kind of length trimming jig for multiple strips, and get a very sharp saw…

All, I think this might have been touched upon a while back, but I can't find where: I'm wanting to start the base for the model, and to do a parquet wood effect. I need to know the approximate scale of the model to get the floor looking right.

Looking at the railing height, from floor to top rail, it's 3" or 76.2mm. A standard real-life height is about 1000mm, so this gives an approximate scale of 1:13

I was given a load of birch wood sections, which I think may have been for OO gauge sleepers:



Which are 4mm wide:



One of the standard parquet floor wood sizes is 60mm x 210mm, so this would give me a scale of about 1:15. I'd say this is close enough for the job.

Obviously I'd have to trim each piece to the correct length (about 15mm), but this would then double or even triple the number of strips I've got to work with. I'd need about 2500 to do the complete floor. I think it would look quite nice:



My thinking is to print the CAD of the floor onto paper, align and glue the paper to the base with PVA. Then in turn PVA each strip in place over the paper. I think it would be strong enough, since I use PVA on paper ship models and there's no way they're ever coming apart.

Any thoughts? Thanks.

By the way are the PEC edge finders available in metric? I’m used to a 6mm diameter cylinder.

Thanks all - mixed reviews, but I’m sure I’ll enjoy it.

Yes you have to wary of assuming everything is cheaper at a show. I was gutted to miss out on a punch and die set ‘on offer’ from the manufacturer at the Telford plastic model show a few years back (they only had one left and when I decided to go back and get it, it was gone). When I checked online the exact same thing - again from the manufacturer- was around £10 cheaper even with postage.

Is the model engineering hobby in decline - hence fewer display models? No idea, but people were saying that 16 years ago when I got my ML7, yet they seem just as expensive now for the same thing. I doubt many people scrap ML7s, so supply would be pretty constant.

Everything seems to get worse the older people get: My Dad always said attending a Grand Prix at Silverstone was best in the ‘50’s & ‘60’s, yet I only knew it as an ‘enthusiast’ from the ‘80’s & 90’s, and thought it was awesome. These days I wouldn’t go if they paid me.

Ill no doubt enjoy the show, and I’ll hopefully pick up an edge finder (I’ll check online prices first though) and some hexagon stock and some BA fasteners; the last lot I got were a nightmare to get delivered. I did buy my 10V kit from Stuart’s at Doncaster, and IIRC they did give a bit of show discount (can’t remember 100% about that though), and of course no postage to pay which made it a worthwhile purchase, plus it’s somehow nice to attend a show and come home with something.

Thanks all.

All,

I'm planning on going to the Midlands show on Saturday. I've only ever been to two engineering shows (Doncaster 2017 & 2018 IIRC) before lockdown. This was before I'd started my 10V, so I'll be looking at things with a slightly different eye now that I have an idea of what's what.

I was wondering if there are any things that you can get at these events that are cheaper than online, or are you better just buying stuff like inserts from say Cutwel and be done with it? Reason I ask is that often you can find things that seem like bargains at events like this, but they turn out to be tat.

So are there any suppliers that regularly attend shows that usually do good deals on inserts or tooling? I'd also like to get an electronic edge finder, but have no idea what to look for or what's a good price for what you're getting.

Thanks!

Thanks all.

All, one of my original Myford drip oilers has never worked properly - despite stripping and cleaning, it’s either full flow or nothing for some reason. The spring often binds on the pin or bore, giving the feeling of gouging metal when turning the knob. I’ve fiddled about with it to no avail.

Years ago I bought a new pair, but they were pretty cheap and nasty and didn’t work well at all.

Where can I get some original Myford oilers? EBay?

Thanks.

Did some length measurements:



Best case end-to-end is 0.01mm difference, worst 0.11mm.

Difference from nominal lengths best 0.05mm, worst again 0.11mm.

(I think I may have twitched when doing an undercut, hence the odd high readings).

Central length is 0.02mm off nominal, overall length, 0.01mm off.

Central diameter is consistent all the way along.

Surface finish looks ok too, so all’s well that ends well I suppose. Now for the bearings.

Ramon, if you read the summary, I mentioned I’d turned the three diameters on one end to the drawing, within the limit of my calipers, so it’s not like I’m totally inept. Using ‘my’ method just ensured the opposite ends were identical. Plus I’ve proved it works with no issue. What’s not to like apart from that some machinists wouldn’t do it that way in industry?

So this evening I machined the shaft using ‘my’ method. I was careful to evaluate after the first pair of diameters. I made up the three slip gauge stacks ready for the three length setups:



To compensate for the centre drill error, I used a piece of doubled-up Rizla paper. I wasn’t bothered about the tiny error anyway, but thought it couldn’t do any harm to try to (approximately) eliminate it.

Apologies in advance for mixing units again, but: Got the metric step diameters spot-on (at least to the 0.01mm accuracy of the calipers), and as discussed, left the final cut tool setting well alone before swapping ends round.

Removing the workpiece and swapping the carrier and re-fitting took less than 60 seconds, so it’s really a non-issue.

DIAMETERS:

The result was 3 out of 3 diameter pairs were identical to within the 0.0005” accuracy of my digital calipers. I then switched to my micrometer (0.0001” accuracy) which showed 1 out of the 3 diameter pairs to be identical, the remaining two were 0.0002” different.

There is no way I could have got that consistency by turning individual ends. Clearly I’m relatively inexperienced and not saying for a second that others couldn’t do it, but for me, this method seemed completely legit, and the micrometer doesn’t lie.

As an aside I asked one of our machinists at work about it (time served, very experienced) and he said he’d turn that particular shaft using exactly the same method; there was no reason he could think of why, if the centre setup was correct, it could ever yield different diameters (assuming no significant tool wear).

I had to make at least one error, and so it proved. The middle continuous turned centre piece was supposed to be 14mm diameter, but ended up 13.9mm due to me forgetting to halve the difference to apply to the tool. Thankfully I caught it at 13.95mm due to incrementing down (I took the 0.05mm off to make final cut a fine one).

LENGTHS

Lengths seem OK to within a few thou, but are difficult to measure. I’ll set up in the mill at some point and use the edge finder to bet a better idea of how accurate and consistent they are.



This is after finishing with fine abrasive. I’ve left 0.25mm on the ends (as per instructions), so the centre drillings will end up a bit smaller:

Also added 0.005” undercuts, just because they seemed to look OK, and would remove any doubt as to binding in assembly.

So whatever the wrongs or rights of the method, I’ve finally got the beginnings of a crankshaft!

Edited By Dr_GMJN on 08/09/2022 23:19:18

Jason, fair enough I’ll give it a go on the two roughing cuts for the crank webs and see what happens. If they’re identical to the limit of my micrometer I’ll crack on. If not I’ll measure and cut each end at a time.