Forgotten engineering techniques

[Larry Coleman 1Participant @larrycoleman1]

Well I have enjoyed the last posts

Believe it or not only engineers think like you have all done and I am refreshed to see you all have different opinions but at the end of the day we all pretty much think alike.

Andy nailed it and is right on the money we are doomed but in our world the pleasure is making something.

Anyway I spent a lot of time scrapeing propellors on to large shafts and believe me I enjoyed it. Scraping of lathe slides is a talent and its done to prevent them from siezing. in the scrapes oil remains. Also honing cylinder bores prevent glazing. All in all a very usefull skill.

Now spotting screws are a big assett in a machine shop, do you know what they are? I will have to take a picture to show you my set. They can be made very easy.

Also my number one computer crashed and this one is number 2 so if I disapear you will know why. I really have it in for Bill Gates.

Danny your friend worked it out in the end and your right.

Andy I am still wondering about that Machedy.

Larry

Edited By Larry Coleman 1 on 13/01/2015 12:47:48

[JasonBModerator @jasonb]

Used spotting screws to get the stay locations onto my hornplates of my TE from the boiler stays. Stan Bray showed them well on his build of the Junior too.

J

[Anonymous]

Posted by Larry Coleman 1 on 13/01/2015 12:44:59:

Now spotting screws are a big assett in a machine shop, do you know what they are?

Yes, thanks; although I don't have a set as I've never felt the need to use them. Still, they'd be simple enough to make, if required.

Andrew

[Mick HayesParticipant @mickhayes12454]

Dear Larry, please do not abuse Bill Gates, Microsoft et al. If it wasn't for them I'd probably still be pulling handles on lathes, instead I'm sitting comfortably in a warm office exercising my brain, not muscle. Considerably better paid too!

[Speedy Builder5Participant @speedybuilder5]

Another good way of transferring screw holes etc, is to use a piece of celluloid (clear plastic) placed on top of the holes, rivets etc, then mark off the holes onto the plastic, drill the plastic and use the plastic as a template for the mating part.
BobH

[Neil WyattModerator @neilwyatt]

I've used a piece of paper tacked in place with pritt. use a pencil just like doing a brass rubbing, or just rub with dirty fingers. Prick though at the hole centres, stick other way up to the bit to be drilled, and use a centre punch to mark out the holes.

Neil

[chris stephensParticipant @chrisstephens63393]

Hi Guys, with this talk of cylinder squares I thought I would make one, well in truth I saw a short length of sawn off motorbicycle fork tube on the floor of the engineerium, just before sliding on it for those who might wonder, and then thought of making a square.

For those on a budget, motorbicycle fork tubes should make good squares being reasonable quality steel and hard chromed. My bit was 33mm diameter and 4 inches long, if you are offended by mixed units, deal with it! I trued it up in the four jaw to within a couple of tenths and took very fine cuts till each end was clean and then de-burred, et voila, a cylinder square. Fork tubes are thrown away at motorbicycle repairers all the time, even if bent (the fork tube not the repairer, although come to think of it…..) there will still be a long enough straight bit to make a couple of squares. Gone are the days when they would be straightened, is that H&S or just more profit in new or,to bring it back to title of this section, a forgotten art?

Now of course I will have to think of a use for it, having survived all these years without.

chriStephens

[Les Jones 1Participant @lesjones1]

Hi Chris,
I would have thought that the outside of the cylinder and the end face would need to be machined without removing it from the chuck. From my understanding of the way you made it it would only be as true as the chuck jaws.

Les.

[chris stephensParticipant @chrisstephens63393]

Hi Les, I could be wrong but if you have reasonable faith in your chuck jaws you should be within home tolerance requirements. If looking for NASA standards, well, what are you doing looking at an amateur's forum.

Given a little time I shall test it for true squareness, but so far it checks out against a new M&W square(?).

chriStephens

[Howard LewisParticipant @howardlewis46836]

Bacon Fat, saved from breakfast and SWMBO, (actually, you are doing both of you a favour) is a useful lubricant, especially for taps or dies.

If you are lucky, a gudgeon pin, (ideally new) from a diesel or petrol engine, will have the ends square to the O D. and so make a good Cylindrical Square. Otherwise, you may need to do some emery work, and a lot of checking, to produce the desired result.

Model Engineers, in particular, and other preservers of old machines (Steam, Vehicle, Motor Cycle etc) are likely to be the ones keeping alive skills which would otherwise be lost. (These range from reading an analogue measuring device, a vernier scale, drilling and tapping, blueing and scraping, and so on).

How many now know how to remove a bush from a blind hole?

Keep up the good work retaining useful legacies and techniques!

Howard

[JasonBModerator @jasonb]

I think I do if it involves oil and a close fitting rod.

J

[Gray62Participant @gray62]

Posted by Howard Lewis on 13/01/2015 18:20:45:

How many now know how to remove a bush from a blind hole?

Removed several gearbox input shaft bronze bearings from the flywheel this way – 3/4 fill bearing with grease, insert close fitting piece of bar and firm clout with a 2lb lump hammer, bearing pops out under hydraulic pressure, piece of card around the bar stops you getting showered in grease

[jason udallParticipant @jasonudall57142]

Re bush removal….
Guess this works best for bushes that have not failed oval…

[“Bill Hancox”Participant @billhancox]

Posted by Bogstandard2 on 10/01/2015 00:26:18:

Here are two links that should help you go back in time to find out what they were doing before modern day gizmos came on the scene.

Just click on any down the list on this one, and save the PDF's

John

Last night I read several pages in one of the old books that was published in 1885. The author very strongly admonished the imperial system of weights and measures and advocated the world wide adoption of the metric system. Interesting opinion for the time. I am saving many of these in PDF and backing them up. One never knows when these may be removed from the site. I have a small number of machining books in the headboard of my bed any one of which I absolutely must take a peek at before I am able to fall asleep. I have read them all several times and will continue to do so. I reckon by the time I am 80 and given that my Mom always cooked our food in aluminum pots, they will probably be new reading to me. Thanks again.

Bill

[Gray62Participant @gray62]

Posted by jason udall on 13/01/2015 18:47:02:
Re bush removal….
Guess this works best for bushes that have not failed oval…

For bushes that fail oval, an expanding mandrel and a puller work well. The ones I use have a serrated outer that grips the bush as they expand, works (almost) every time

[chris stephensParticipant @chrisstephens63393]

Hi Les, My four jaw must be far worse than I thought/hoped, I checked the cylinder square using standard methods and you are right it is miles out, I read a total lean of 1 thou in four inches, read on both ends equally. Still for this amateur bodger that will have to do till I resurrect the surface grinder.

chriStephens

[Anonymous]

Out of idle curiosity I measured the cylindrical square I have, made by the late father of a friend, who was a toolmaker. As one would expect the diameter is better than ±0.0001" and the perpendicular errors about the same over 4". It shouldn't be difficult to hit pretty much the same numbers if I were to make one at home.

Andrew

[jason udallParticipant @jasonudall57142]

Coal burner…quite aware..my comment was a suggestion that the close fitting pistion/hydraulic punch technique wouldn’t work if the hole was not round or was damaged such thar an adequate seal couldn’t be obtained…I guess its not funny if you have to explain. .sorry. .

[Gray62Participant @gray62]

Jason – no need for apology, just sparked a thought of one of the other methods we use to get the bushes out

[jason udallParticipant @jasonudall57142]

‘ so ‘kay

[jason udallParticipant @jasonudall57142]

‘ so ‘kay

[Bob Brown 1Participant @bobbrown1]

If you use grease you can still get the bush out using a punch, can get a but messy so a bit of rag keeps it retained, you have to give it a really good whack like you mean it, Mr Angry helps. or pop a rubber O ring into the hole having filled it with grease first.

Or run a small diamond shaped chisel down one side till the bush can be collapsed in, all sorts of ways to skin a rabbit.

How many uses can a good chisel can be put to? not the ones for wood!

Here's your starter for 10, cutting sheet material in a vice.

[Robert DoddsParticipant @robertdodds43397]

Chris,
All is not lost with your cylinder square They are a bit like broken watches. They are right two times a day! Cylinder squares are right at two places around the periphery even though they lean at other positions but I agree with Les. the cylinder should machined parallel between centres and the end face machined at the same setting and be relieved to ensure the cylinder stands on it's rim and avoids the centre. If you machine it with the bulk of the bar up the headstock spindle you dont know what its doing even though you set it true at the chuck jaws. Done properly the cylinder becomes the master to which you offer up the commercial blade for checking.

Bob D

[chris stephensParticipant @chrisstephens63393]

Hi Robert, all is not lost because, so far, I have not found the need for one.

I do realise that machining all over is the only true way to make one but I figured that the fork stanchion would be a wizard way of getting the parallel bit done for no effort, especially as it was literally lying around on the floor. I could easily file the ends true, after all it is only a few microns that need to come off. Or, I could hold one end trued in the four jaw and the other trued in the tailstock. I will make a dedicated squareness checker first, instead of relying on a lash up, before bothering either way to remove any measuring inaccuracy.

Thanks for your comment

c

[Bill PudneyParticipant @billpudney37759]

A friend of mine uses coconut oil when cutting threads in or on Grade 5 Titanium, I've used it on EN36a, 4140 and 12L14 (en1a ish) steels and hard, light alloys (2024 and 7075). It works a treat, especially when warmed so it becomes slimy. It seems better than the proprietary stuff. Possibly a Vegan replacement for all those animal fats?

Get it from your local friendly health food shop.

This is a really good thread init.

cheers

Bill

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