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Member postings for Joseph Noci 1

Here is a list of all the postings Joseph Noci 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Insulating board that won't drop powder as it is touched
29/03/2020 15:38:40

Do you have a product called Pratleyperl in the UK? It is made from the mineral perlite. A really remarkable thermal insulator and is mostly used in bead form and laid on your ceiling for insulation. It is also used mixed with cement to plaster house walls for insulation, which I have done to my house on the Namibian West Coast and the result is great - huge reduction in heating/cooling requirements. . Raw beads weigh about 100kg/cubic meter. Also, mixed with cement, used to insulate ovens, furnaces, cryogenic storage, etc.

Basically mix, dry, with cement in 3:1 volume, then add water till a firm mix, and form into the shape you want. A test I performed was to make a 25mm thick slab, about 200mm square, and cure well. An Oxy-Acetylene hot flame played onto one face till the surface was orange/red, with the flat of my hand up against the opposite side - warm but far from uncomfortable to keep my hand there!

You can make any shape you want, and it does not seem to powder much, unless you rub two like surfaces together.

The only heat insulator that would not do that is probably in the family of ceramics.

Joe

Thread: Is this guy nuts, or sensible.
29/03/2020 08:59:00

Bugger getting a Bridgeport down the ladder..

Thread: Minilathe/Mill motors
28/03/2020 14:04:16
Posted by An Other on 28/03/2020 12:20:59:

I have had a 7x12 'chinese' lathe and mill (X1 type) for many years now, and have had the usual trials of failing control boards and motors several times. I know there are many different motors/controllers fitted to these machines, but I refer to the older versions (I think 250W or 350W brushed motor)

While fixing these problems, I have collected various circuit diagrams and info relating to these machines, and as a result have a question: ..............................

The drive circuit (via two IRFP450 IGFTs) is apparently identical in all the circuits I have.

Could you possibly scan the variants of schematics you have and post them here? Could perhaps then give better advice re the differences between them, and the implication regarding the motors you have in mind.

Robert, if you read as posted : (via two IRFP450 IGFT's) - you may have read IGBT, but AnOther did NOT say they are IGBT's - he is quite correct - those devices ARE insulated gate field effect transistor, also known as MOSFET's....

Also, you said - This design can usually be identified by the presence of two identical large electrolytic capacitors in the rectifier circuit. These are in series for 120V and parallel for 240V operation.

Not so...The capacitors are normally in SERIES for 240v Operation.....parallel connection for 240VAC would require a change of underwear.

AnOther, If we can see your schematics, it will be a doddle to see if the DC bus is run as a doubler, etc.

Joe

Thread: Digital callipers shows time not distance
22/03/2020 06:28:12

Maybe measuring the speed of light tween the caliper tips? Measure up your foot - should read around 1ft or so, or maybe 1nanosecond...

Thread: vfd question
21/03/2020 06:53:54

John, maybe this may help - I believe it is a setup for your VFD.

Parameter P78 thru P85 seem to be current settings ( in mA). This example is set for 7amps (7000mA)

Voltage settings, max and min frequencies, etc, to be set as you need, not necessarily as per this example!

Joe

 

vfd settings.jpg

Edited By Joseph Noci 1 on 21/03/2020 06:55:03

Thread: What are you reading?
20/03/2020 21:32:57

Are there any folk here using a Kindle? We are somewhat starved of reading material here in Namibia, especially in Swakopmund - the local Library is very poor in stock...

Book Stores are likewise very limited - we have two (!) book shops in Swakop, one mostly German, the other very small.

I am considering a Kindle, but feel a little insulted by Amazons 'license' agreement - you may read but not own the book you buy, and Amazon seems to be legally able to revoke your license anytime, and you lose the book(s) you purchased. Not sure what you have to do to have the license revoked..

Also, it seems to me that the book prices on Amazon are quite high?

I hate reading a book on a tablet though - I like to have the book in hand - easy to flip back to refresh on something, etc. And the book smells good...However, I have depleted the Library's stock, both bookshops, and buying paper books from abroad is becoming difficult here.

Any Advice on a Kindle?

Joe

19/03/2020 20:03:29

Terry Pratchett, Robert Rankin, Robin Hobb ( Farseer Trilogy..)

Wireless World, QEX Magazine...

Joe

Thread: Electrolytic capacitor
17/03/2020 20:40:03
Posted by Neil Wyatt on 17/03/2020 20:16:45:

So it's YOUR satellites ruining all my astrophotos, Joe!

Neil

Sorry....

Send you some Lionphotos instead?..

Thread: Fitting Stepper Motor to 2.125" x 7" Small Lathe.
17/03/2020 14:15:45

Yep, as Dave said - sharing the stepper driver power bus with your other electronics, arduino, etc, is really not recommended.

Andy, I suspect your stepper supply also powers the Arduino? ( via regulators, etc..) That also makes the opto-isolation in the stepper driver somewhat useless...

It is NOT recommended to use a common supply for stepper and processor - Voltage spikes become common and destructive - small steppers are probably ok, but still..

John, you correctly mention the holding current, etc - note I did say that the stepper is easily turned by handwheel with the driver power OFF..

Terry, a simple test - fit a handwheel of sorts to the stepper shaft, connect the stepper to your stepper driver, without power, and turn the handwheel. If it turns freely enough, ignore the lack of a problem, and get on with it..

Joe

Thread: Electrolytic capacitor
17/03/2020 12:52:59

Supercaps are generally 2.7v max, so higher voltage requires series connection and balancing of the voltage across each cap.

Very useful devices - not only for real time clock backup, etc, but are being trialed starting internal combustion engines in the stop-go mode in city driving. Live much longer than the rechargeable cells, charge very rapidly - 10 to 100's of seconds, etc.

I build Wildlife tracking collars ( Lions..) which are powered from a 3.6v lithium cell - a D cell, 17AH type which is tailored for long life at typical max 150mA draw, due to a non-trivial internal resistance.. The Iridium Sat modem in the collar draws tween 300 and 400mA intermittently during a 30 second period in which it transmits the collar position via satellite to our server. A 5Farad supercap in parallel with the battery makes this possible - it supplies the large currents thanks to its very low internal resistance, and is replenished slowly by the battery. 4 hours later, when its time for another position transmission, the supercap is long fully charged again.

It also allows wringing the last bit of energy from the battery as well.

A neat device!

The green device to the right of the PCB's top center through bottom center - a 5F supercap


sat tags in assembly.jpg

Thread: Fitting Stepper Motor to 2.125" x 7" Small Lathe.
17/03/2020 12:15:05

Don't worry about it. All modern stepper electronic will not have a problem. The coil driver FETS/Transistors are all sized to suit coil back EMF amplitudes that occur during coil switching, and all have protection diodes to clamp said energy. You need to wind the stepper quite fast to generate such voltage levels, and even if that voltage got past all the protection diodes ( and the reverse diodes intrinsic to the FET), the base electronics of the stepper driver are all fed from voltage regulators, which would protect the electronics anyway.

John Haine says:

Steppers get very stiff back driving when the power is off. Not so bad if you can disconnect from the driver. If the power is on back driving is very difficult and "ratchety". A clutch, disconnecting the drivers, of arranging a manual encoder, would be best.

With Stepper driver power OFF, I have not found any impediment presented to the manual rotational effort by such action - this with quite a variety of Chinese stepper controllers, varying from 35vDC to 80vDC max input, and current ratings from 2A to 10A.

I just went to test again on my lathe and shaper - no noticeable resistance at all - the lathe has a 4NM stepper, the shaper X axis has a 16NM stepper running 10amps at 90V peak.

Joe

Thread: Toolpost question
14/03/2020 11:52:09
Posted by Mark Braham on 13/03/2020 10:08:51:

Jusr had a lovely message from PeWetools in germany, telling me his story about his multifix toolpost and the devopments using china as his supplier, was a very i interesting read.

Interested to see what PeWetools had to say - My experience with the Chinese Create Tool holders was excellent - Instead of repeating it all , if interested the relevant posts are HERE

Peruse the whole page of posts, but maybe from 12/07/2017 is more to the point

Joe

Edited By Joseph Noci 1 on 14/03/2020 11:53:58

Thread: Some very good talent
13/03/2020 10:24:08
Posted by XD 351 on 13/03/2020 07:40:51:

I watched this again for the 3rd time and the only time you will see him applying cutting fluid with a brush is in the first scene where he faces the stainless bolt - after that it is all dry .

Not wishing to be pedantic..Look at 1:24 thru 1:34 or so - clearly see oil running down the sides of the cylinder while drilling. Just cos we did not see the brush does mean it was not applied. - a Chap with the skills he has would do the job right, I think..

13/03/2020 07:14:55
Posted by XD 351 on 13/03/2020 06:49:34:

Not Dissing it but ..

I always get a chuckle when they use cutting fluid with carbide tooling but not when drilling with a HSS drill which would benefit more especially on stainless .

I must be blind! I tried to find where the cutting fluid was used with the carbide tooling and could not! But I did see quite reasonable amounts of cutting/lubrication oil in all the drilling operations.

Joe

13/03/2020 05:45:46

Neat work, esp as a machining exercise!

Instead of trying to rob its contents, though, just take the whole safe home to your lathe - or drill press..

Thread: CBN advice seeked.
12/03/2020 17:17:25

Great! Glad you came right. I really believe in supporting people like that. They make a good product and deliver good service.

Regards

joe

Thread: Desoldering how to?
11/03/2020 07:51:11

I use solder wick extensively - once you have the feel, it works very well. A HOT iron, with sufficient thermal mass, and quick work..

Also use a solder sucker for things like the 1 or 2 mm square legs of big transistors on power amps - else cut the legs and remove easily one by one.

For finer stuff I use these tools ;

A board pre-heater-

pre-heater.jpg

Hot Air pencil ( goes to 450deg C)

From 6mm to 1.5mm orifice.

hotair1.jpg

hotairtip.jpg

And most useful of all for SMD work, and for DIP IC removal. Tips also available for QFN, etc..

Metcal Tweezers, up to 40watts /tip

tweezer1.jpg

tweezerdip.jpg

Joe

Thread: Shaper Vice?
11/03/2020 06:12:28

Now that's a vice...

shapervise.jpg

10/03/2020 17:27:48
Posted by Bazyle on 10/03/2020 16:11:22:

I think the point is the fixed jaw is at the front of the machine, so the cutting force is into it. Then when you think about getting the screw handle to be also at the front for convenience of operation you end up with the moving jaw having to be pulled towards the front - hence screw under tension.

Do you mean 'pushed towards the front' ? ( by the shapers stroke)

Also, I would like to see the typical large milling vise screw fail by kinking when used one the shaper!

 

 

Edited By Joseph Noci 1 on 10/03/2020 17:28:52

10/03/2020 15:21:48

I believe the shaper vice screw is under tension while a 'normal' vice screw is under compression - I have a shaper and such a vice and I believe the theory is that when planing in the screw axis with a compression screw, toward the screw, the cutting force may work against the compressed screw, thereby releasing the vice jaw pressure and allowing the work piece to move.

I am not sure why there is a supposed better chance of compressing the screw as opposed to stretching it if under tension..

Joe

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