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Type: Posts; User: BobL
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19th Jan 2021, 11:28 AM
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When you buy a replacement motor I recommend...
When you buy a replacement motor I recommend buying one with twice the HP of the original. This will to some extent overcome the loss of motor power at <50Hz.
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19th Jan 2021, 10:57 AM
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Unfortunately the motor will almost certainly be...
Unfortunately the motor will almost certainly be a 1450 rpm motor so it won't be good at either of these tasks although a pair of pulleys and belt couple be employed as an RPM doubler?
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19th Jan 2021, 10:49 AM
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A friend of mine bought a new DP for $450, and a...
A friend of mine bought a new DP for $450, and a used 3P motor for $50, he removed the motor froth DP one and sold it for $100.
Swapping the motor sounds easy but there are a few other things to... -
18th Jan 2021, 10:06 PM
Thread: Workshop vacuum cleaner
by BobL- Replies
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6" of mercury = ~20.3 kPa about the same as a...
6" of mercury = ~20.3 kPa about the same as a Ryobi Wet and Dry Vac.
Most household vacs should pull 16-18 kPa, maybe consider getting new filters and check seals as they also probably also have... -
18th Jan 2021, 02:58 PM
Thread: Workshop vacuum cleaner
by BobL- Replies
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If that is 6" of water column then that is not so...
If that is 6" of water column then that is not so good ~1.44 kPa
If its 6 psi then that's really good max vacuum and is equivalent to ~40 kPa
Festool vacs have 24kPa and my old Ryobi is 21kPA.
... -
18th Jan 2021, 07:23 AM
Thread: Dust masks
by BobL- Replies
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$2400 from BOC, $1600 for older models on ebay.
$2400 from BOC, $1600 for older models on ebay.
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17th Jan 2021, 11:34 AM
Thread: Workshop vacuum cleaner
by BobL- Replies
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That's basically what I did for my grinding dust...
That's basically what I did for my grinding dust collector which is connected to my 4HP wood dust extractor.
The cheap silver (aluminized mylar) has some heat resistance so it doesn't matter if... -
17th Jan 2021, 11:32 AM
Thread: Workshop vacuum cleaner
by BobL- Replies
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That's basically what I did for my grinding dust...
That's basically what I did for my grinding dust collector which is connected to my 4HP wood dust extractor.
The cheap silver (aluminized mylar) has some heat resistance so it doesn't matter if... -
17th Jan 2021, 10:34 AM
Thread: Multi purpose tool mounting system
by BobL- Replies
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I've seen a few different floor mounted...
I've seen a few different floor mounted tool/machine posts. One I was thinking of copying was a socket made out of ~100x5mm SHS set into the floor. It was actually recessed into the floor and had a...
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16th Jan 2021, 09:40 PM
Thread: Workshop vacuum cleaner
by BobL- Replies
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It depends to some extent if you use lube or not....
It depends to some extent if you use lube or not.
I do use lube so I like using a wet and dry shop vac as they have a sort of "settling out" chamber that reduces the amount of oily swarf swarf... -
16th Jan 2021, 09:30 PM
Thread: Dust masks
by BobL- Replies
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I bough mine about 15 years ago from Carbatech....
I bough mine about 15 years ago from Carbatech.
I think mine cost $299
But I don't think they are being made any more - can't see them for sale online anywhere.
Carbatech now sell the Trend... -
15th Jan 2021, 08:41 PM
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To compare those two you need to multiply the 2.7...
To compare those two you need to multiply the 2.7 by SQRT 3 so then it comes to 4.7A?
Unless those VFD display amps are @415V
Yeah could be the meter but maybe not the wave form - more... -
15th Jan 2021, 08:06 PM
Thread: Dust masks
by BobL- Replies
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For that sort of thing I used a battery powered...
For that sort of thing I used a battery powered full face respirator with 2 x P2 cartridge filters.
Once the batteries had run down a bit mine lacked sufficient air flow for use on cold days so it... -
15th Jan 2021, 06:32 PM
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, VFDs usually show per phase current so x...
,
VFDs usually show per phase current so x sqrt(3) to get total current.
That means 6A per phase = 10.49A total
But are those currents @240V or 415V?
If its at 415V you are going to be well... -
15th Jan 2021, 06:30 PM
Thread: What did you learn today?
by BobL- Replies
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I'm on my second pair of lefties. For short...
I'm on my second pair of lefties.
For short welds I usually don't wear a right hand glove at all, and if I wear a right hand glove I usually wear a TIG glove as it provides better feel than standard... -
15th Jan 2021, 04:24 PM
Thread: Dust masks
by BobL- Replies
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what sort of dust?
what sort of dust?
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14th Jan 2021, 05:33 PM
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It's not only the simplest scenario it is also...
It's not only the simplest scenario it is also the safest scenario for both the VFD and the motor. Unless suitable precautions are taken there should be no switches between the motor and VFD. Turning...
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14th Jan 2021, 11:25 AM
Thread: 6V car horns on a 12V car
by BobL- Replies
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I had 12V Klaxon on 6V VW Beetle and it sounded...
I had 12V Klaxon on 6V VW Beetle and it sounded like a drunk toad.
If you run one on 6V and one on 12V you will get two frequencies and two sound volumes. a couple more and some different... -
14th Jan 2021, 12:34 AM
Thread: 6V car horns on a 12V car
by BobL- Replies
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Yep just put the 2 , 6V horns in series across...
Yep just put the 2 , 6V horns in series across the 12V and you will be sweet!
They will of course have to both sound off at the same time -
13th Jan 2021, 12:16 PM
Thread: Size of supply cable for induction motor?
by BobL- Replies
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Sorry to nit pic here but the rated current on a...
Sorry to nit pic here but the rated current on a motor nameplate is not really the max current a motor can draw. Most motors can draw a lot more current that their rating if they are overloaded. eg...
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1st Jan 2021, 01:26 PM
Thread: Cheapest MIG that'll do the job?
by BobL- Replies
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This is mostly correct but I think it's less so...
This is mostly correct but I think it's less so for welding.
Back in the 1970's I mucked about for about 5 years with stick welders, bought and borrowed a few welders, watched pros welding,... -
30th Dec 2020, 09:51 AM
Thread: Size of supply cable for induction motor?
by BobL- Replies
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While I prefer black or grey, most of the 3P...
While I prefer black or grey, most of the 3P machines in my shed are on orange cable from a roll. A couple years ago I found a roll of about 20m of of grey 600V 6 core cable in a skip which I have...
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29th Dec 2020, 09:27 PM
Thread: Size of supply cable for induction motor?
by BobL- Replies
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If you intend purchasing new I found it is...
If you intend purchasing new I found it is usually cheaper to buy an extension cord and cut the socket end off than it is to buy the plug and same rated cable separately.
Eg at Bunnings:
HPM 3... -
29th Dec 2020, 07:54 PM
Thread: Size of supply cable for induction motor?
by BobL- Replies
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A few years back my young bloke worked for an IT...
A few years back my young bloke worked for an IT company that go all their extension and computer cords tested and tagged but it was cheaper to just buy new cords. He collected up the old cords and...
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28th Dec 2020, 12:14 AM
Thread: Hercus in Kenya.
by BobL- Replies
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Humm - with death rates per million from...
Humm - with death rates per million from diarrhoic diseases of about 10,000, HIV/AIDs (~8000) and TB of about 1200 I suspect they're not too worried about the pandemic.
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27th Dec 2020, 01:53 PM
Thread: Economical Milling
by BobL- Replies
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I'm not a big time user but I've used the Ausee...
I'm not a big time user but I've used the Ausee ends mills and they seem OK
It doesn't always suit but I've found I can do quite a few things using a small fly cutters for which the tool tips can... -
27th Dec 2020, 12:38 PM
Thread: Lubricant for Vices
by BobL- Replies
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I have some white Li grease as a spray, bought a...
I have some white Li grease as a spray, bought a new can last year.
The spray is semi penetrating - I use it for lubing WW machinery.
I generally blow the dust off the thing I'm (re)greasing,... -
27th Dec 2020, 12:11 PM
Thread: Lubricant for Vices
by BobL- Replies
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I use moly wheel bearing grease - its supposed to...
I use moly wheel bearing grease - its supposed to be good for slow-motion high-pressure applications. My 1967 purchased join vice got lubed that way in the 1980s and is still good and smooth.
I also... -
26th Dec 2020, 01:10 PM
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I use the "Vibration" App by Diffraction Ltd....
I use the "Vibration" App by Diffraction Ltd. It's only for iPhone/ipad etc.
There are plenty of others out there.
Some only measure the frequencies but you need ones that measure the accerlations... -
26th Dec 2020, 11:38 AM
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I have heard of using an old diamond/stone...
I have heard of using an old diamond/stone cutting wheel as a dressing tool but not tried that myself.
Before you go that route I found there are two other aspects ie runout and vibe, that are worth... -
23rd Dec 2020, 07:42 PM
Thread: Dwindling steel supplies
by BobL- Replies
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Talking to my steel fabricator mate and he...
Talking to my steel fabricator mate and he doesn't seem to have any problems at the moment but he has heard the prices are going to rise in the new year so he's bought extra basic stocks. If others...
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23rd Dec 2020, 12:45 PM
Thread: Cheapest MIG that'll do the job?
by BobL- Replies
- 37
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Yes we need you to better define your jobs,...
Yes we need you to better define your jobs, mainly sizes of job, and thicknesses of materials and how often you wish to do this
eg , bird cage , sheep cage or cattle truck, - daily - weekly -... -
22nd Dec 2020, 06:27 PM
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Sounds like a Hercus would meet your needs and...
Sounds like a Hercus would meet your needs and most models also start at around 50rpm.
Using a vector drive VFD and a 3P motor that has twice the original motor power I can spin mine at about 15 rpm... -
21st Dec 2020, 11:08 AM
Thread: Motor Braking using DC injection !
by BobL- Replies
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I tried using 150W incandescent as a braking...
I tried using 150W incandescent as a braking resistor on a VFD and it was savage.
There was a flash of bright light and it stopped almost instantaneously BUT the motor made a loud Thump/Grawnch,... -
20th Dec 2020, 12:09 PM
Thread: Motor Braking using DC injection !
by BobL- Replies
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Yeah keep meaning to install a contactor (I even...
Yeah keep meaning to install a contactor (I even have a couple of suitable spares in my stash!) but have only had to replace 3 relays in about 7 years. I bought a 6 pack of these relays for another...
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18th Dec 2020, 08:54 PM
Thread: Motor Braking using DC injection !
by BobL- Replies
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Now that I think about it the 500W max relay I...
Now that I think about it the 500W max relay I use on my 3HP TS has only failed when I have turned the saw off under load eg jammed the blade and then turned off the motor. Free running the saw...
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18th Dec 2020, 07:34 PM
Thread: Motor Braking using DC injection !
by BobL- Replies
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Rather than reinventing the wheel maybe a have a...
Rather than reinventing the wheel maybe a have a read of this?
https://www.hw-group.com/cs/podpora/how-not-to-destroy-a-relay
The relay on my 3HP TS switch is rated at 16A/230V
But reading the... -
18th Dec 2020, 07:04 PM
Thread: Motor Braking using DC injection !
by BobL- Replies
- 63
- Views
- 1,925
Rather than reinventing the wheel maybe a have a...
Rather than reinventing the wheel maybe a have a read of this?
https://www.hw-group.com/cs/podpora/how-not-to-destroy-a-relay
The relay on my 3HP TS switch is rated at 16A/230V
But reading the... -
18th Dec 2020, 02:42 PM
Thread: Motor Braking using DC injection !
by BobL- Replies
- 63
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- 1,925
It depends on the HP rating of the motor but from...
It depends on the HP rating of the motor but from memory those relays have a rating of about 300 (if you are lucky) switching operations for a 2HP inductively loaded, switching operations.
Even... -
18th Dec 2020, 09:26 AM
Thread: More metal bluing
by BobL- Replies
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Somewhere amongst my bluing posts I referred to...
Somewhere amongst my bluing posts I referred to how difficult it was for a DIyer to buy concentrated nitric acid for use in the bluing process which is understandable as concentrated nitric acid will...
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17th Dec 2020, 05:04 PM
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It really depends on size and amount of work you...
It really depends on size and amount of work you do. My first D bottle lasted 9 months. These days I get 18 to 24 months from a D size as I went back to using stick for most of my regular steel...
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17th Dec 2020, 12:47 PM
Thread: Scrap metal score
by BobL- Replies
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Scrap metal score
Went to visit an old mate yesterday who owns/runs an intermediate size metal fab shop, fabbing stuff mainly for local and mining industries. The businesses was set up by his dad about 60 years ago...
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17th Dec 2020, 09:22 AM
Thread: Air Compressor Recommendation
by BobL- Replies
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I run my ebay cheapie misters at 35 psi and slow...
I run my ebay cheapie misters at 35 psi and slow flow rate, just enough to wet the cutter and work piece area being machined. If the mister is having trouble aspirating the lube/coolant you might...
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16th Dec 2020, 09:08 PM
Thread: Air Compressor Recommendation
by BobL- Replies
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That sounds like a lot of air for a mister, what...
That sounds like a lot of air for a mister, what pressure are you using for the mister?
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16th Dec 2020, 09:36 AM
Thread: Scotch brite belts
by BobL- Replies
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If you are thinking of sewing, try dental floss....
If you are thinking of sewing, try dental floss.
I made this strop belt about 13 years ago - don't use it much but its still together after all that time.
All the sewn edges are cut on a slope so... -
15th Dec 2020, 09:46 PM
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I wondered about this especially as standard LED...
I wondered about this especially as standard LED lights effectively produce white light ie all colours. However, there could be a difference between cool (bluer) and warmer (yellow) LEDs - see below....
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15th Dec 2020, 05:56 PM
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The Argon is not destroyed in the welding...
The Argon is not destroyed in the welding process. It is harvested from the air (air contains about 1% Ar) and the welding process returns it to the atmosphere. What is "lost" is the energy needed to...
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14th Dec 2020, 09:08 AM
Thread: Older eyes and welding vision
by BobL- Replies
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The problem with using a mask to avoid welding...
The problem with using a mask to avoid welding fumes inside a shed is that for lowest exposure masks have to be continually worn for some time after welding has been completed. Just because the dust...
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13th Dec 2020, 05:00 PM
Thread: Joplin vice colour
by BobL- Replies
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The 4" Joplin I bought in 1967 - which I still...
The 4" Joplin I bought in 1967 - which I still have and still use is black but that is a fabricated (not cast) vice.
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12th Dec 2020, 11:40 AM
Thread: More metal bluing
by BobL- Replies
- 99
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A few things that went through the bluing process...
A few things that went through the bluing process this week.
These have only had 4 passes through the fuming tank.
Though the black is not as "deep" as for 7-8 passes it seems to be enough to...