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Member postings for Hopper

Here is a list of all the postings Hopper has made in our forums. Click on a thread name to jump to the thread.

Thread: Tribological query re shafts and bushings!
17/05/2021 10:40:18

How would they have been made in the factory? Diecast? Extruded? Sintered? They look an awkward and wasteful piece to machine from the solid.

17/05/2021 05:25:53

+1 on Duncan's suggestion of sleeving the original bushings. Oilite or leaded bronze/gunmetal bushings could be fitted too. Or even cast iron. All will run well on unhardened steel shafts.

Otherwise, if making whole new bushes you will have to machine a keyway into them and install a key. Sounds like wall thickness is not enough for that though if it is 10mm bore and 14mm OD? You would only have 2mm wall thickness. So you might have to go with 1mm wall thickness for any sleeve bushings you install. Machine the ID undersize and press/loctite them in then machine the final ID in situ. Bronze would work better for such thin walls than cast iron or oilite.

Edited By Hopper on 17/05/2021 05:29:08

Edited By Hopper on 17/05/2021 05:32:15

Thread: working Damascus steel
17/05/2021 05:12:35

If I could avoid machining Damascus, I would. Depending on how well made it is, it could tend to pic up on the edges of the laminations while being machined, which could be a real nuisance. Or it might be ok. Only one way to find out...

Thread: Machining castings in the 4-jaw - knocking?
17/05/2021 04:43:58

I'm not sure what you mean exactly by "slowest open gear"? Presumably not using back gear, so about 200rpm? In which case you should try slowing down and using the fastest back gear speed, about 100rpm. It looks like the casting is about 4" long, which makes it the same as turning a 4" diameter job. So for HSS tooling you need about 100rpm absolute maximum. Then for interrupted cuts, a bit less again. So maybe even the intermediate back gear speed of about 50rpm. Slower speed = less force of impact = less flexing = happier lathe. This job is exactly the type of thing Myford provided the back gear for.

It's often best to grind the hard skin off such castings before machining. The bench grinder or a 4" angle grinder will do the job. Or even a small Dremel type grinder if you take your time. Otherwise, the lathe tool will tend to skid over the hard surface instead of cutting. And counterintuitively it's best to take a deep cut that gets in below the hardened skin area and into the softer metal below it.

Which brings us to the next point. Those are some fairly flimsy castings and holding them in the four-jaw is probably allowing them to move/flex around a fair bit under the impact of cutus interruptus. That is probably why the large pads at the end machined better than the smaller, less supported ones in the middle.

You would be better off to clamp your castings flat onto the faceplate to machine them. Or even use small screws to attach the castings to a piece of stout flat plate and hold the plate in the four jaw, or clamp the plate to the face plate. These methods will give you support behind the whole casting at the back, not just the four points where the chuck jaws are holding them.

Also, you want to keep tool overhang to a minimum and topslide extension to a minimum too. And lock the carriage. If using HSS tooling, a round nosed tool or at least one with a decent radius on it can heip stop the point getting snapped off by the impacts of interrupted cutting.

Some pics of how you held the jobs in the chuck and how you had your tooling and slides etc set up would help identify what your problems may be caused by too. But I would try using back gear low rpm and grinding the hard skin off as first steps.

 

Edited By Hopper on 17/05/2021 05:04:20

Thread: Lathe run out
16/05/2021 11:55:54

16mm. Yeah that should take the weight!

Drill your holes a bit oversize to make the tapping easier.

Thread: Shortening HSS drills
16/05/2021 11:49:55
Posted by ega on 16/05/2021 11:08:48:

I had some old style square taper shank drills with a brazed-on taper.

I guess they never slipped in the chuck!

I guess not! Probably they went in those old two-jaw drill chucks that had a 90-degree V notch in each jaw to grip the square shank. I remember my grandfather had some old woodworking drills like that. Not sure how it all worked.

 

Edited By Hopper on 16/05/2021 11:51:28

Thread: The future is Tiny
16/05/2021 11:24:01

I think battery weight is becoming less of an issue with the new Lithium batteries and apparently there are several other types in development that are better again.

Meanwhile, in Australia they are electrifying at the other end of the vehicle scale. Converting heavy long-haul trucks to electric with quick-change battery packs. They can travel 400 to 600 kilometres (350 miles) on one battery pack, then they pull in to a battery station and the guys whip the flat battery out and install a freshly charged one while the driver takes his mandatory anti-fatigue meal/coffee break.

The company that does the electric conversions to existing trucks has set up the battery change stations at existing truck stop sites where drivers already take their mandatory breaks, so no loss of travel time. They say it costs $80,000 to do the conversion and will save that much in fuel costs in one year.

We have the sunshine to make this kind of thing work with recharging via solar too.

Thread: Lathe run out
16/05/2021 11:14:07

Nice work. I think you will need a second nut on each screw to enable you to adjust and then lock in position. Or are you doing something tricky there?

Thread: Shortening HSS drills
16/05/2021 11:05:30

Most likely. Although they don't say anything specifically about the blanks before they go into the oven or whatever that first machine is. Seems in this day and age it would be a lot of faff to weld on stubs to save a few cents worth of HSS. Maybe more likely on something like a 1/4" drill with a MT2 shank etc. but I think they were more common years ago than now.

Interesting to see their factory is still pretty hands-on labour intensive. Real mid-20th century style to it.

16/05/2021 10:03:19
Posted by AdrianR on 16/05/2021 08:38:40:

 

I always thought drills were made in two parts and welded together. It seems that would be easier than trying to do HSS heat treatment at one end of a drill.

They used to be made that way. Or so we were taught at tech college in the 1970s. I never actually worked in a drill factory! Was told it was mostly a cost saving measure as HSS was once upon a time exotic and expensive. Supposedly also allowed a little more flexibility and bend where the hardened HSS would crack and also allowed the chuck to grip the softer shank. I vaguely recall we were told the two parts of the shanks were friction welded together by rotation of one against the other stationary one. (You can do this with steel bar in the lathe at 800rpm if you like experiments.) Possibly also induction welding etc in later years. You could actually see the join and the two different coloured steels on some old drill bits.

It seems these days most smaller size drills are full HSS as the price of the material has come down. I would think some larger drills, especially those with large Morse tapered shanks larger than the fluted section of the drill are still probably made from two pieces welded together.

So if your Dad's bits are old, they may well be made in the old two-piece blank way. Worth keeping them as most of those old drill bits were pretty good, much more so than the cheap hardware store offerings these days.

Edited By Hopper on 16/05/2021 10:06:37

Thread: Any tips for aligning mill vice / workpieces?
15/05/2021 09:20:29

Mount your vice semi-permanently near one end of the table, not in the middle. Then you can use the rest of the table for other jobs and move the table to the one end when you want to use the vice. Relies of course on your machine having a long enough table and travel and small enough vice etc.

Thread: Tailstock pressure
15/05/2021 08:52:22

For a beginner with limited mechanical background, a revolving centre has a higher survival rate.

Thread: Shortening HSS drills
15/05/2021 08:48:58
Posted by DC31k on 15/05/2021 08:25:23:
Posted by bernard towers on 14/05/2021 23:36:20:

Shortening jobber drills is OK for the odd job but they still flex as the shank is soft where the true stub drill is all hard

Could you please provide an explanation of how stiffness (which is a function of Young's modulus and geometry) correlates to hardness. Thanks.

Possibly because the soft shank is drill rod, aka silver steel, or the like whereas the hardened fluted part is HSS.

14/05/2021 10:27:36

Yes you can. The HSS usually goes all the way to the end of the flutes. Be aware though that the web in the middle of the flutes gets thicker towards the shank end of the drill so you may have to thin the web at the tip on the corner of the grinding wheel. Not needed on countersinks where there is already a hole in the job in that area of course.

Edited By Hopper on 14/05/2021 10:28:19

Thread: Inherited ML7 in need of some love - where to start?
14/05/2021 09:54:54

The clutch visible in the posted pics back on page 1 of the thread looks to be mounted outboard of the original ML7 pulley rather than inboard like the later Super 7 type clutch. Maybe it was a Grandpa Special? Further pics would clarify.

Thread: Tailstock pressure
14/05/2021 09:46:10

I have five bob each way and lube with moly grease at the outset and drip a little oil on the centre as I go just to be sure. But it's a rare job where I use a dead centre these days. Only if utmost rigidity and precision are needed or when using a ground away half centre to allow access to a small diameter job etc. But I have a revolving centre with the two-angle tip that is just as good in all but the most extremely small cases.

Thread: Lathe chuck guards - how many folk use them?
14/05/2021 09:38:55
Posted by Martin Kyte on 14/05/2021 09:13:11:
Posted by Joseph Noci 1 on 14/05/2021 07:17:40:
Posted by Martin Kyte on 13/11/2019 14:55:30:

Whatever you want to do in your own workshop and whatever you think of Health and Safety you cannot refute the fact that workplace injuries and deaths have reduced considerably over time. See Charts 5 to 7

**LINK**

regards Martin

But so has that type of industry as well..as attested to by many, many dozens of posts lamenting the fact..The surviving big production shops using manual turret lathes, etc, are few and far between - the big boys CNC machine's dangerous bits are all behind interlocked doors...Reduce the industry and you reduce the injuries.

The graphs are per 100,000 workers not total injuries. Industry size does not factor in the rate. If anything production has increased per unit production even if there are less units producing.

CNC has helped too but is that not just changing the way we work?

regards Martin

regards Martin

The figures are for all workplaces, not just industrial. I think since 1990, workplaces have become less and less industrial and more and more office work. Lathes have been replaced by computer printers. Milling machines by photocopiers. Stamping presses by coffee machines. Inherently a less hazardous working environment. Ergo, fewer serious injuries.

Many of the worst injuries have been "offshored" to China where safety standards are on par with our 19th century levels if the videos one sees are at all typical. Stamping presses without safety guards just make me shudder, having worked around them for some years but in the time when safety guards were mandatory and thorough.

Thread: Machining a female MT1 taper
14/05/2021 09:13:07

I think I'd keep it simple and use option 1.

Might be different if it were a precision grinder spindle and we were working to a tenth of a thou. But for a wood lathe spindle, and providing your four jaw chuck is in good condition, option 1 should work ok. A bit of patience with the four jaw and you should be able to set it up to zero runout or within a couple tenths of a thou, before drilling, boring and reaming the internal taper.

Be very careful with the final fitting of the taper. They can disappear down the hole rather quickly at the end. A very small increase in diameter can translate into a surprising amount of lateral movement. Maybe have practice on a bit of scrap to get a feel for achieving the final fit.

Thread: 45% Silver Solder for Jewelry?
14/05/2021 08:33:05

Zinc should be ok. Same stuff as used on galvanised water piping. Ditto copper.

Thread: Lathe chuck guards - how many folk use them?
14/05/2021 08:28:43

I must have used dozens of lathes over the years and never one had a chuck guard. But that was in ancient times when men and limbs were disposable. Still do it at home on the Myford though.

If you want to see what a lathe can really do to a human being, Google "Man dies after pulled into lathe machine at work in Russia" and look at the video from Russia that pops up. WARNING!!! It is extremely graphic so if you have any tendency to PTSD don't look at it. Poor blighter leaned over a large lathe to wrap some emery tape or something around a revolving job, got caught and ended up all over the workshop, literally. Gave me a whole new respect for machines I took for granted all my life. I worked on lathes that size as a 17 year old apprentice onwards with never a thought that such things could happen.

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