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Workshop and fixit stuff

Started by Dave, July 10, 2017, 07:26:50 PM

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hermes2015

Quote from: Dave on February 28, 2018, 07:01:23 AM
Quote from: hermes2015 on February 28, 2018, 07:00:08 AM
That's fascinating. I love this stuff.
Any interesting screws that you need to research, Hermes?

;) Oh, the stories I could tell you, but you're a bit young.
"Who is to say that pleasure is useless?"
― Charles Eames

hermes2015

I wish the whole world would just go metric. It would eliminate so many of these annoyances. Another irritation is the different electric plug standards in the world; one has enough other issues when travelling as much as I do.
"Who is to say that pleasure is useless?"
― Charles Eames

Dave

Quote from: hermes2015 on February 28, 2018, 07:03:53 AM
Quote from: Dave on February 28, 2018, 07:01:23 AM
Quote from: hermes2015 on February 28, 2018, 07:00:08 AM
That's fascinating. I love this stuff.
Any interesting screws that you need to research, Hermes?

;) Oh, the stories I could tell you, but you're a bit young.

:geezersay:

OK, Old Man.
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

Dave

#138
On the subject of interesting threads and screws, of the helical type, one of my favourites is the "Merton nut"

QuoteIt consisted of a 'chasing lathe' by which he cut a secondary helix on the same cylinder with a tool mounted on a 'Merton nut' lined with strips of cork pressed upon the primary lathe-cut helix. Periodic errors were thus averaged and eliminated by the elasticity of the cork.
(Wiki)

Merton nuts use cork or felt or some other compressible/elastic material, soaked in a lubricant, that is in a housing that compresses it onto a helical thread. Correctly adjusted it is virtually "slop free" in all directions yet easy to turn.

A square thread form is best but it can still make an almost back-lash free adjuster using triangular ones. Obviously the greater the end load the longer the Merton nut needs to be, but in some cases the load actually works in your favour - providing the cork etc is well contained. I once made one out of hardwood for a quick and temporary prototype test rig. It actually lasted long enough to work out the theory was duff anyway . . .

Like several other things, including my own design high speed, just about constant volume/velocity/pressure (just a very fast, very small pressure spike) shiny, stainless steel and bronze change-over fluid media valve, it is one of the things I would have liked to have taken with me from work! Tried to get the boss interested in looking into a patent for that valve but he could not be bothered.

Added later:Just discovered that the life and writings of Thomas Merton are quite interesting - though some are a bit wooish.
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

Bad Penny II

Quote from: hermes2015 on February 28, 2018, 07:12:35 AM
I wish the whole world would just go metric. It would eliminate so many of these annoyances. Another irritation is the different electric plug standards in the world; one has enough other issues when travelling as much as I do.

I agree the world should go metric, remember that space mishap?
Well no I don't remember it specifically but I know it happened.

I don't want any kilo-pascals in my tyres though, PSI till I die.

Grams are good, ounces are so antiquated probley >$30 now.
Humans are still measured in ' and " though.
TV/monitors are still a hold out.
I'm not sure what my shoe size is, it varies.
The standard "glass" of alcohol is miserly small.
Why is a sea X a bit bigger than a land x?


Take my advice, don't listen to me.

Recusant

As long as the tires are marked with both, I don't care, but it's somewhat troubling when the tires only have a psi rating and one is confronted with a pump that only displays kPa. OK, you can divide by 7 and add a few, but that's only a very rough approximation.

In Europe, at least on the continent, they seem to measure humans with the metric system, but for human weight in the UK it's still stones.

As for nautical miles and land miles, they have completely different origins and ideally the same word would never have been used, but that's the English for you. Fanshaw!
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


jumbojak

Today's project was a chuck replacement on my drill. It's fairly new and very nice except for the factory chuck. Milwaukee decided to build a cordless drill that has enough power to dislocate your shoulder if you aren't bracing the side handle properly but cheapen out on the chuck. It's an all aluminum job with terrible runout and an annoying habit of letting go of large auger bits and hole saws....

Not only that but - getting back to the topic of odd thread pitches - they used a 9/16 thread to mount the chuck to the arbor instead of the ubiquitous 1/2. It was a challenge to find a high quality chuck that fit the drill but I did eventually find one made by Rohm. Then I had to find a distributor. Then I had to convince the distributor to sell me one single chuck when their minimum order was $500. Then the slick bastards had it drop shipped from Rohm. Pocketed to difference between wholesale and retail with a click of a mouse!

I'm happy though. Think I might go drill some four inch holes in irrigation pipe and see it this thing can flip me over. At least there's no cord to get tangled up in.

"Amazing what chimney sweeping can teach us, no? Keep your fire hot and
your flue clean."  - Ecurb Noselrub

"I'd be incensed by your impudence were I not so impressed by your memory." - Siz

Icarus

Metaba also has some drills capable of dislocating a shoulder. I suspect that they have metric chuck threads. I do not own one of those but I have used one that is astoundingly  torque capable.  I have an ancient Milwaukee corded hammer drill that has been faithful for near 35 years. 

Recusant

Not precisely apposite, but since drills came up I thought I'd mention a Canadian review channel on YouTube that I've found entertaining and sometimes educational. The fellow seems to have some engineering knowledge and he disassembles the items to examine their workings before he ever turns them on.

In the US and Canada there's a discount tool shop called Harbor Freight. Some of their items aren't too bad but you have to be picky and avoid their real junk, which plenty of it is. I could go on, but here's his review of their "Hercules" drill that they're promoting as a competitor to DeWalt.

"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


jumbojak

I like aVe, not so much for the technical stuff but his mangling of the English language is highly entertaining. He's a bit too much of a fanboy for Snap-On and Hilti. Both brands do produce excellent products but I don't find them to be a good value when you factor in the astronomical pricing schemes.


"Amazing what chimney sweeping can teach us, no? Keep your fire hot and
your flue clean."  - Ecurb Noselrub

"I'd be incensed by your impudence were I not so impressed by your memory." - Siz

Dave

#145
Quote from: jumbojak on March 09, 2018, 02:49:24 PM
I like aVe, not so much for the technical stuff but his mangling of the English language is highly entertaining. He's a bit too much of a fanboy for Snap-On and Hilti. Both brands do produce excellent products but I don't find them to be a good value when you factor in the astronomical pricing schemes.

First time I have seen the guy but, yes, he has an excellent command of Manglish! But, somehow, you know exactly what he means in the context. Might even adopt a few of his terms!

Just taken delivery of a new (cheapish at £230) digital 'scope, Hantek DSO5102P. Just getting my head around the functions and menus but not sure about the constant 2mV "grass" on the trace - it's on both channels even when I put a shorted plug in and does not alter with X or Y scaling. That makes it look like it is being introduced after all the signal processing  during or after the A-D stage. Seems to average 15MHz, way below the 100MHz bandwidth of the device.

Have sent an email to the seller (in China of course), nothing about this in the reviews. Although it is "fulfilled by Amazon" I have just noticed that returns have to be direct to China! I am not doing very low voltage stuff so may have to put up with it. The trace on my little, cheapo pocket 'scope is cleaner, but that has other bugs.

Otherwise the functions, menu system and the display of signal detail etc are very good.
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

jumbojak

I looked at the Hantek scopes but the reviews were poor enough to steer me away. The hardware is apparently decent in within its limits but the software is reported to be real junk. I settled on a Pico 2204A and couldn't be happier. It's a bit more money and only two channels but works very well. I'm still accessorizin.

"Amazing what chimney sweeping can teach us, no? Keep your fire hot and
your flue clean."  - Ecurb Noselrub

"I'd be incensed by your impudence were I not so impressed by your memory." - Siz

Dave

Quote from: jumbojak on March 09, 2018, 04:16:32 PM
I looked at the Hantek scopes but the reviews were poor enough to steer me away. The hardware is apparently decent in within its limits but the software is reported to be real junk. I settled on a Pico 2204A and couldn't be happier. It's a bit more money and only two channels but works very well. I'm still accessorizin.

The Amazon reviews over this side were OK, mostly 5* and the 4*s were minor things applicable to intended ussge. Basically I am doing low frequency digital hobby stuff so, assuming no gross  distortions, wave shape is unimportantish. Timing is a bit more critical though . . .
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

hermes2015

Quote from: Dave on March 09, 2018, 03:05:32 PM
Quote from: jumbojak on March 09, 2018, 02:49:24 PM
I like aVe, not so much for the technical stuff but his mangling of the English language is highly entertaining. He's a bit too much of a fanboy for Snap-On and Hilti. Both brands do produce excellent products but I don't find them to be a good value when you factor in the astronomical pricing schemes.

First time I have seen the guy but, yes, he has an excellent command of Manglish! But, somehow, you know exactly what he means in the context. Might even adopt a few of his terms!

Just taken delivery of a new (cheapish at £230) digital 'scope, Hantek DSO5102P. Just getting my head around the functions and menus but not sure about the constant 2mV "grass" on the trace - it's on both channels even when I put a shorted plug in and does not alter with X or Y scaling. That makes it look like it is being introduced after all the signal processing  during or after the A-D stage. Seems to average 15MHz, way below the 100MHz bandwidth of the device.

Have sent an email to the seller (in China of course), nothing about this in the reviews. Although it is "fulfilled by Amazon" I have just noticed that returns have to be direct to China! I am not doing very low voltage stuff so may have to put up with it. The trace on my little, cheapo pocket 'scope is cleaner, but that has other bugs.

Otherwise the functions, menu system and the display of signal detail etc are very good.

Is there a published signal to noise ratio spec on the instrument?
"Who is to say that pleasure is useless?"
― Charles Eames

Dave

Quote from: hermes2015 on March 09, 2018, 04:53:46 PM
Quote from: Dave on March 09, 2018, 03:05:32 PM
Quote from: jumbojak on March 09, 2018, 02:49:24 PM
I like aVe, not so much for the technical stuff but his mangling of the English language is highly entertaining. He's a bit too much of a fanboy for Snap-On and Hilti. Both brands do produce excellent products but I don't find them to be a good value when you factor in the astronomical pricing schemes.

First time I have seen the guy but, yes, he has an excellent command of Manglish! But, somehow, you know exactly what he means in the context. Might even adopt a few of his terms!

Just taken delivery of a new (cheapish at £230) digital 'scope, Hantek DSO5102P. Just getting my head around the functions and menus but not sure about the constant 2mV "grass" on the trace - it's on both channels even when I put a shorted plug in and does not alter with X or Y scaling. That makes it look like it is being introduced after all the signal processing  during or after the A-D stage. Seems to average 15MHz, way below the 100MHz bandwidth of the device.

Have sent an email to the seller (in China of course), nothing about this in the reviews. Although it is "fulfilled by Amazon" I have just noticed that returns have to be direct to China! I am not doing very low voltage stuff so may have to put up with it. The trace on my little, cheapo pocket 'scope is cleaner, but that has other bugs.

Otherwise the functions, menu system and the display of signal detail etc are very good.

Is there a published signal to noise ratio spec on the instrument?

Not that I can find. Have found a fairly comprehensive manual, with typical applications, in pdf form but no mention of signal:noise in the spec. I watched three video reviews on Youtube, by guys seemingly knowing what they were talking about, and not one commented abiut the fuzz - even the one who directly compared it to a Tektronix job (of which it is almost a copy). Learned a few other things, without recourse to the manual, but dearly want the graticule a bit brighter - you have to be at 90o to the screen and turn the turn the sun/light off!. Though all the important stuff, frequency, period, amplitude, rise time etc are, as with all digital scopes probably, available in real numbers. There are two frequency displays, one "hardware" and one "software" that never quite agree, but even the Tektronix had the same problem.

All three commenters gave it a thumbs up for the price.

So, perhaps I am just being fussy? Still too used to good old valve 'scopes (like the one in my attic that is probably a health hazard now!)
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74