Member postings for Mike Hurley

Agree, don't get too hung up on the technicalities at the early stages. Get you hands on an assortment of bits (many metal merchants sell assorted 'short ends'  and see how you get on - you'll learn as you go. But, just turning for its own sake will soon get pointless and you risk losing interest.

Get a couple of books about lathe work that include simple projects - doesn't matter much what those are - but you will learn a huge amount much quicker by having a specific job to complete where you will need to work to tolerences and with differents materials / finishes etc.

Either way, enjoy yourself and don't stress. In many years time as an experienced model engineer then you will need in depth knowledge of the 'right' materials.

Take care. Mike

Edited By Mike Hurley on 16/08/2021 09:56:34

Thanks for the feedback guys.

JasonB - The piston rod and part of the crosshead are a one-piece forging. I have been trying to retain as much of the original parts as possible, and I've already had to modify the ends where they attach to the pistons as those were completely ruined and had to be re-made, but due to severe wear and missing material I had to modify the connections into the piston which now leaves no room for further change. I do take on board your comments about positioning though.

Ian, Had considered this, but my concern here would be re-aligning things after joining as there wouldn't be any room for error as both ends are abviously currently in line, and the tinyest error would stop the smooth running of the mechanism.

Howard / mart. : I'll have a look at how feasible that idea is. Cheers

regards to all.

My 3 x 5 victorian twin steam engine restoration is plodding on, but have come across yet another stumbling block when trying to assemble everything. Due to subtle internal dimesional differences in the two cylinders, (which I should have accounted for but missed!) I found that one conn rod is now a matter of about 4mm too long between bearing centres!

I can't just re-bore the little end in the new position as that would leave no bearing material at the front. I don't think I can just bore a bigger hole for an oversized pice of PB and re-bore as that would leave little steel support top & bottom. One thought was to sweat in a piece of steel to replace the current PB bearing, then re-bore in the new location for a bearing, But am unsure if this would work.

It was a huge job making these conn rods out of solid, so have no desire to repeat the exercise! Any suggestion please?

Dimensions: (mm) overall 250, little end bearing 22 od x 15 bore. 15 deep.

You may not realise, but it's now getting more worthwhile to collect any scrap you have knocking about and pop to your local metal recycling people if one is handy. Its surprising how much the value has inreased over the last 12 months and even small amounts can soon add up!

If you haven't done this before, you may need to 'register' with them and get a certificate, but it's quite straight forward and is supposed to discourage unscrupulous people stealing things like cableing from railways etc.

Often the case Jim, you learn a lot more by trying things out for yourself and finding what works best for your own combination of tools and meterials. There can be so many combinations of factors that affect a job and sometimes the standard rules just don't apply. But still remember that many of these 'rules' have been created by many good engineers over many, many years so are grounded in the real world and apply to the vast majority of tasks..

Just a caution here, many years ago my brother was severley ill with a massive allergic reaction after making a nest of Iroco coffee tables, admittedly in a less than desirable environment. He was VERY ill, and never had anything similar before or since when working with other timbers. Apparently the dust from sanding is a know bad allergen.

Just thought it would be worth a mention.

Take care. Mike

Interesting reading the article on the 'poor mans shadowgraph' in the MEW back issues. Just a bit time consuming for me to tackle at present as its just really an odd one-off job , but many thanks for the suggestion John.

I'm trying a few more versions of some of the earlier suggestions (wax, plastics etc) to try and get a sharper profile, and possibly try a scanner as suggested if I can get a reasonable 'moulding'. They are quite old & not exactly pristine threads, so not too hopeful of the outcome but can only try ones best. I then need to determine the angle of taper (ready to cut new 'plugs' / stopcocks or whatever ends up going in them 'oles!) as I'm not assuming that's going to be any standard either, but will be easy enough to do.

Thanks again for all the feedback guys.

On an engine from the 1850's all the threads are Whitform so far (I've had to repair numerous to date on this machine) some being heavily corroded. The ones in question don't look to bad in comparison but are obviously not in pristine condition so not easy to get a precise 'image' of them. Funnily enough as per your suggestion Michael, I've just gone out and checked and a Metric thread does match pretty well 100%! Could be someone has re-cut it many, many years later and they only had metric kit to hand?

With the limits of equipment / techniques available I don't think I shall be able to precisely differentiate between 25, 25.4 & 26TPI, so I think it will be a case of cutting test pieces of each in brass or alloy and see what is the best fit!

Regards, Mike

Lots of lovely, useful feedback!

Michael : I greased the thread then squeezed a pellet of epoxy putty on it. Result was reasonably sharp and I compared it under high magnification against my thread gauge, certainly didn't appear to closely match 24 or 26, but was near as at 25.

Nigel - it's a horizontal engine. Originally there was ONE tapered 'plug' in situ. Rather stupidly (on reflection) I assumed it was the correct one and spent about 2 days on and off duplicating a second one exactly the same. Only to happily discover that didn't fit. After the usual round of bad language, discovered the thread I was duplicating was 20TPI and the hole was - as per the object of this thread - much finer. Oh joy. Someone in the past had simpy jammed in what was to hand - fortunately doesn't appear to have cross threaded either hole!

I'll look into the possibilty of the BSB (not something I was familiar with ) even with 26 TPI may be able to squeeze something in at a pinch. If they were for drain cocks, I would assume they would be of brass so logical to use a complimentary thread? BTW however, there's no provision for similar at the other end of the cylinders.

David: Never thought to use the 'wood' trick, you learn something new every day. Thanks

Really appreciate the time and effort all have taken to respond. I'll try and update you on how I get on.

Mike

My 3 x 5 twin Victorian steam engine restoration plods on. The cylinder ends each have a threaded hole which I naturally assume was for some kind of fitting. The only things that come to mind are drain cocks

.
My main query is about the thread size, it measures 1/2" OD ot the top, with a core about .48" narrowing to around .46" about 3/8" in. but it's 25 TPI. I've checked this numerous times. I just cannot seem to find any reference anywhere to 25TPI standard threads at these sizes (e.g. BSP / BSPT).
Are these just one-off specials or is there some obscure 'standard' I've just not been able to locate?
Also, I was under the impression that drain cocks weren't necessary on older slide valve engines, as any water build up can be forced out via the slide valve lifting off its seating. If so, what other purpose could these threaded holes serve?
Any thoughts appreciated.
Regards Mike

I saw the Clickspring video use of a fine filing machine, seemed perfect for the job, but seemed a much smaller, precision instrument than the one I commented on.

Originally when I saw the item for sale I got the impression it was a much heaftier piece of kit, so not in the ordinary clockbuilding arena? Still I suppose in the past, they had to have a way to cut similar sized square holes in much larger gears i.e. for big church / town hall type jobs?

Bob - cunning use of the 2 stroke engine! I really like that, well thought through.

I can appreciate the use for making neat square holes in the absence of broaches etc.

all the best. Mike

Noticed a filing machine in the ' for sales ' . Must say it's one machine I've never had any experience of, but was struggling to think of what purposes / advantages it would have over traditional lathes, mills or shapers?

I've made one off roller guides to aid filing small parts consistently in the past, and am still an advocate of manual filing at times - sometimes being quicker than setting up a machine tool for a one-off.

Anyone got any thoughts?

I do believe a memorial is being officially unveiled today at Normandy for the British who died . Isn't it going to be on TV?

Saw an article about it in the week interviewing one of the veterans

Rod just beat me to it!

Edited By Mike Hurley on 06/06/2021 10:21:13

Use something similar on my rotatry table for holding a spare myford chuck. Just have to be careful on direction of feed / cut to avoid it unscrewing. The plain part is locked in situ with a couple of screws. Only use very occasionaly anyway.

Welcome Mark. Once the staring at the new lathe phase is over (we all do that with new toys) do you have any ideas what sort of things you're looking to do with it? Interested in any particular field or just looking to get general machining experience, There are chaps on here that are more than willing to help whatever the route.

Enjoy

All the best. Mike

Thanks SoD for the warnings, I shall definately take them on board and probably avoid this experiment all together!

Redsetter - had comsidered this but its about 70Kg and quite an arkward shape to heave around. It's currently on a simple stand so that I can work on it, one plan is to eventually make a HD wheeled truck so I can move it easily if I want to take it any Steam rallies etc ( if and when they happen again)

Anyway, thanks for the input both. Take care

Mike

Thanks for the suggestions guys - all very useful info.

I had overlooked that it is in fact double acting, so needed to figure that in my volumes! I think I now have some indication of the sort of values I need to work with, and useful methods on determining necessary pressures / air volumes that may be involved.

Bazyle's idea of oil barrels and water is quite interesting and may well be something worth examining just out of interest, particulary after having had a quick look at the daily cost of hiring compressors of the sort of sizes suggested in the thread! However, after the time and effort (and not inconsiderate cost in materials and tooling) involved in the restoration over the last 3 years, I might just have to grin and bare it.

It's primarily a case of determining that its basically sound and operational before investing more time and effort in this project.

As usual, thanks again to all for taking your precious time to read and respond. All the best. Mike

Thanks Howard, I'm not expecting miracles from compressed air, just a basic 'does it go round at all' ? and no major leaks, rattles, bangs and bits dropping off etc. Speed wouldn't be much of an issue at this stage.

I know there is a big difference between c/air and steam in engines like this, but at present it's just one step at a time. I just don't want to go to the trouble of getting a source that will be too underpowering and then not know if its an issue with the engine.

Mike

With any luck, hopefully in a short while I will be in position to test my refurbishment of the 3 x 5 Victorian workshop steam engine ( as detailed in the Work in progress forum ). To that end I'll initially run on compressed air just to check basic functionality ( or lack thereof! ).
My question to the assembled experts is 'how much' ? I shall need to hire, beg steal or borrow a suitable compressor or source but have no idea what capacity would be needed, having zero experience with such matters. I did a search on the forum but the few results were related to quite small models and I'm not sure if the info would scale up.
The 2 cylinders are 3" bore and about 5" long with a sweep length of 4" giving a volume of 46.6 cu in in total. They have a 90 degreee angular rotation difference. Would I be correct to assume a straightforward multiplication of total cylinder volume x theoretical target RPM would give me the required CFM? Sounds far too straightforward to be honest though.
But pressure at that capacity? - I have no idea what sort of figures we are talking about. Also need to factor in the fact that everything should be a bit tight at first.
Any pointers most gratefully received.
Regards Mike