Member postings for Hopper

7 thou is not much. Just make the packing gland a loose fit and let the packing fill in the gap. Teflon can do wonderful things. And make the piston a loosish fit, maybe even a little barrel shaped to allow a little angular clearance. Use a viton o-ring as piston ring and let that do the sealing. James Watt did not run one thou clearances in his engines. Some of his engines ran 1/8" piston to bore clearance and more.

Plus a bit of clearance on all the pins and links and piston rod bearing will all add up to provide some relief as Jason says.

As Mr Harley famously said to Mr Davidson: A little extra clearance never got in the way.

Edited By Hopper on 06/02/2023 23:26:45

That's a lot of HSS to grind away. And by the time you get down to the smaller diameter, there will be little or no flute left. Step drills have smaller flutes on the small diameter part.

Nice to have such useful family heirlooms. Much handier than overstuffed chairs and Wedgewood china.

Sounds like there is quite a history to them.

Edited By Hopper on 06/02/2023 12:08:56

I think you will find SAE 4141, like the more common 4140, is a high tensile alloy steel along the lines of chrome moly, and thus not easy to machine for model purposes. Usually used for high-load industrial shafting and gears etc.

1144 is the usual "stress proof" steel some US model makers like to use for delicate crankshafts in model IC engines etc but not at all necessary for general modeling use.

Yes I have used a block of aluminium there. But never had a badly stuck chuck so would advise caution as you say.

There have been previous threads on stuck chucks so you might do a site search on the topic.

Impact rather than steady force will often shift such things (and gear pullers too), done within reason. Something like hold a hex or square bar etc in the chuck with a big spanner on the hex and hit the spanner with a rubber mallet  or soft hammer etc. Others have suggested a large shifting spanner over one of the chuck jaws, but I have not tried that one.

Edited By Hopper on 06/02/2023 11:57:33

Edited By Hopper on 06/02/2023 11:58:11

I know nothing bout the brown stuff. Tis a mystery to me. Woeful for the grandson and nephew of two master cabinet maker/ carpenters whose skill left me in awe. But I do know our Aussie railways used to have jarrah sleepers and they worked well. Since they have now mostly been replaced on main lines by concrete or steel sleepers, you can hear the train wheels singing and squealing for miles on the curves through the hills. So I would say you are right about jarrah's vibration damping effects.

Couple of tips I would offer:

1. Buy yourself a copy of LH Sparey's book The Amateur's Lathe. It has the best description I know of how to grind lathe tools. Start with his "Knife Tool". 8 Quid from Tee Publishing. Well worth every penny.

2. Don't let the HSS overheat enough to turn blue. You've lost the temper if it does. Keep a large tin of water by the grinder (2 litres at least) and dip the tool in frequently before it gets hot on the end. Keep it in there until stone cold.

3. Use 1/4" square HSS and sit it on suitable 1/8" packing in the toolpost to bring it up to 3/8" high. Much quicker and easier to grind than huge chunks of 3/8 HSS. And thus does not get as hot. See point 2.

4. Use a good quality 6" bench grinder with good quality wheels. Get a diamond wheel dresser and use it when needed.

5. If using carbide tooling use the ground inserts that are coded for instance CCGT rather than the standard CCMT etc etc. These are made with a sharp edge for turning aluminium but work well on steel in small lathes.

Edited By Hopper on 06/02/2023 11:39:01

Just part of a standard drill set that went up in 64th increments. Possibly used as a loose clearance drill for half inch bolts, or to drill the hole before using a 9/16 reamer.

EDIT: Could have been a clearance hole for half inch hot rivets used in architectural ironwork in those days too.

Edited By Hopper on 06/02/2023 00:45:58

We had a piece of copper pipe in the en-suite bathroom develop a pinhole leak and flood our 20-year-old house while we were away on holiday for three weeks. New carpet required. Plumber told us oh yes, common thing. Copper pipe coming out of China in recent years has lots of pinholes that let go like this all the time. I had him replumb it along the outside of the wall. Quality ain't what it used to be.

Edited By Hopper on 06/02/2023 00:37:04

Yes it sounds like that may be the case. Their website LINK says that starting March 29 the museum will open from noon to 4pm Wednesday through Saturday but says the boilers and engine can be seen in action on special steaming days, but the link to special steaming days has nothing listed yet. So definitely not every day but maybe one day a month or fortnight or whatever. Not so much coal shovelling after all, then. I suppose there would be plenty of maintenance to do in the meantime.

Yes. The Super 7 has a spindle lock but the ML7 was the budget model when it came out in 1946 and never changed much. I reckon Myford sold a lot of new backgears over the years as a result.

Tell your mate to keep the spindle thread and chuck threads lubed with Never Seize etc and it should not happen again. (There was a thread on this recently with many varying opinions on what works best for this but this is what works for me!)

And i forgot to mention is easiest to take the whole belt tensioning H-frame off the lathe and work on the pulleys and countershaft on the bench where you can properly support the pulley while tapping out the countershaft.

Stuck chuck. If you grip the spindle in the vice be sure to do it b between where the bearings go so there is no risk of damaging the bearing surfaces. Hard to get good grip like that though. I would try to loosen it up with the spindle still in the lathe. Myfords recommended way is to grab the belts and spin the spindle backwards with a block of wood under one of the chuck jaws so it smacks into it. Not sure how much force you get like that though.

If you look in the photo I posted above I am pointing at a pin I drilled and either threaded or Loctited into the bull wheel (don't remember which) and then made a tool below that locks the spindle for chuck removal. YOu can do something similar by jamming a block of wood between the little Allen head screw on the back gear drive dog and the headstock casting. Then you can put a length of wood between the chuck jaws as a long lever to yank on. Heat might help too. Be careful not to overheat the spindle and melt the white metal bearings though. Heat the chuck body only.

Paul, that would explain it then. Things sound a lot more laissez-faire than they once were, and still are in Oz and the USofA. I think boilerman has almost become a job of the past with a lot of modern automatic controls making boilers almost an unmanned operation these days.

Interesting that with all the strict rules on tiny model steam boiler constructions and inspections and approvals we hear of, that the operating side of full-sized extremely dangerous boilers is so relatively lax.

Wouldn't be a bad job running the engine, as a sort of retirement hobby job. Part time for 9 months a year. But yes only paying pocket money for someone with the qualifications and experience to actually do it. I definitely wouldn't fancy the coal shovelling position though!

Edited By Hopper on 05/02/2023 04:16:19

Oh yes a regular bonafide know-it-all, me. Except I forgot you have to take that shaft out to change the belts thanks to the closed H frame set up.

And of course the main bearing caps have to come off to remove the headstock spindle. So you might as well check the up and down movement of the spindle and remove a layer or two of the laminated shims if needed.

It's a bit different from driving locos or traction engines. To operate a large stationary steam boiler like the one at the mill you need to have a boiler operator's license, which requires in the UK under the BOAS scheme at least 6 months supervised experience running a boiler plus a training course plus passing the test. Steam boilers that size are extremely dangerous pieces of equipment with the potential to flatten an area the size of a city block if they explode. The WHS authorities and the insurance companies don't let any old untrained numpty run them.

In the past, to "drive" a stationary steam engine like the mill engine in question, you had to have what was termed an Engine Driver's License. Not sure what the status on those old piston engines is today. Today's licences are aimed at steam turbines and don't mention old piston engines.

I was just surprised the the job ad person specification made no mention of the boiler license requirement, which would seem to me to be the first prerequisite, having worked for some years running large boilers and steam plant. It is usually a very highly regulated workplace.

I certainly never would set foot in such mill if I knew the boiler operator was not trained. tested and licensed. Disaster waiting to happen.

Edited By Hopper on 04/02/2023 23:52:31

Your test bar is a bit long. Usual recommendation is 25mm diameter and 100 to maybe 150 long. At 200mm you are probably getting some flex adding to your taper when taking a test cut. Try it with 100mm sticking out for a more accurate reading.

That said, if you want to turn a long shaft, you will need to support it at the end with the tailstock centre, which will need aligning to turn parallel, separate from getting the bed parallel.

If twisting the bed to get it to turn parallel, I would shim under the tailstock mounting feet on the lathe bed, not the cabinet base. But the cabinet feet could work too so you could give it a try.

Edited By Hopper on 04/02/2023 23:25:53

I don't remember any problem getting that large countershaft pulley off mine when I did it up some years ago. It is held on by a woodruff key and one grubscrew. Trick with those types of pulleys is to never put force on the outer rim. If you have to use a puller, hook it up to the central hub, or a metal plate or bearing puller clamshell behind the central hub. And heat from a propane torch should be enough to make it fall off without a puller anyway. Cheap torch that clips on to a disposable can of gas will do the job.

From memory, the keyway in the three-step pulley goes all along the bore so it can come off either way. It has two grub screws that need removed first. Same as above. Don't put pullers on the outer flanges. Support the inner solid part of the pulley, heat it, and tap the shaft out.

You don't need to pull it apart unless you plan to replace the Oilite bushes. A clean out with solvent and re-oiling should do the job if grease is the only concern.

When fitting a new belt, it is worth getting the "cogged" V belt that has the notches around the inside diameter. They run better around the tight bends of small pulleys like the Myford's.  They are AX series belts rather than the standard A series. You can see the belt in this pic.

Edited By Hopper on 04/02/2023 23:11:06

+1 on both Tubal Cain's ME Handbook and the Workshop Practice series. Always a good starting point.

Re identifying material in your scrap box, you can't really. There are so many different types of steels and brasses and bronzes and aluminium these days, that you are best off to buy in what you need and if there are leftovers, mark clearly with a paint pen or letter stamps etc. I keep my silver steel in a special separate container clearly labelled so it does not get mixed up with the bright mild steel rod etc.

There are old books with descriptions of identifying some steels etc from the coloured sparks produced when held against the bench grinder which might distinguish between a carbon steel and mild steel but not that easy to do.

Edited By Hopper on 04/02/2023 11:34:46

It's not easy to get a boiler or engine driver's licence. It requires quite a bit of study and passing the government examination. Then you have to have a fairly lengthy period of on-the-job training under supervision of a fully licensed operator. Not sure how long that is these days, but would be at least 3 months on the boilers and possibly a year on the engine. That's why I was mystified to see no mention of needing these licenses to start with.Unless they have a senior engineer on site overseeing them and they have the necessary licenses, but the ad reads like the engine driver is the senior operator in that role.

Edited By Hopper on 04/02/2023 11:15:09

Edited By Hopper on 04/02/2023 11:28:45

Look at the salary. For someone with a boiler ticket or engine drivers ticket it is a part time job paying two thirds of that stated salary, which I think was about 20K quid full time. And not really a retirement job for an old timer, shovelling coal into a boiler. And any younger bloke with those licences can make a lot more money than that in industry, power stations, on the rigs etc.

Edited By Hopper on 04/02/2023 11:13:18