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Thread: What did you learn today?
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28th Sep 2017, 01:54 AM #691I needed to lift one side of the column 0.023"Cheers, Joe
retired - less energy, more time to contemplate projects and more shed time....
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28th Sep 2017, 07:39 AM #692Golden Member
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Well ........ you couldn't see the column leaning over but you could certainly see that the cutters were always cutting troughs rather than flat surfaces. I had a lot of difficulty cutting things square and ended up doing the best I could and getting away with it because I have never had to do anything particularly accurately and was always a bit nervous about tramming it....
For example on my biggest cutter, the 2.5" facemill, was always cutting 0.006" lower on one side than another, you could easily see the "step" as the "back edge" of the cutter traversed the workpiece after the "front edge" had already traversed it, whereas now its far less than 0.001" different, just the faintest touch as the "back edge" of the cutter traverses the workpiece.
So that's still not as good as good as it could be, but hey, maybe its the best it will ever get, its an old round column machine and I am a relative newbie to milling so will learn slowly how to get it all working as well as I can.
Edit couple of hours later :Whoops ..... just realised there could be something wrong with that particular cutter .... ie if it wasnt truly square to its own MT3 taper then it would also cause it to behave that way. Will do some more checking today.
BillLast edited by steamingbill; 28th Sep 2017 at 09:55 AM. Reason: added "Whoops :....." + minor edits
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2nd Jan 2018, 10:36 AM #693Most Valued Member
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For the umpteenth million time I again learn't that when ones accidentally knocks a pressure pack can of CRC (and the like) off the bench it inevitably falls onto the spray nozzle breaking off the nozzle and outlet flush with the lip of the can.
well I think I may have found the answer to prevent it from happening
20171220_183004[1].jpg
use a spray nozzle from a can of fly spray?
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15th Mar 2019, 06:24 PM #694Golden Member
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Winning combination : Shear tool on tiny lathe
Have been learning how to use one of those tiny sherline lathes. Got one second hand recently. Pulled it all apart, cleaned and oiled. Looks fine, almost zero wear on the ways.
Xynudu has made a series of videos about them so I won't post too many photos. His videos are good.
https://www.youtube.com/watch?v=gM-xEoLnROI
Mine is a very old one with the brass ways and cross slide and the dark blue finish made in Australia before 1972 according to official Sherline site. Same as Xynudu's.
Have made a tiny piston for a tiny steam engine- 3rd time lucky, broke the first two through ham fisted clumsiness - piston head is 3mm diameter and shaft is 1mm. (Tubal Cain Jenny Wren engine) photo attached.
Whilst making the piston discovered that I can take 3 whisper thin fluffy dust cuts with the shear tool whilst only advancing the tool a total of 0.001" - thought that was quite astonishing. If the rpm are too fast the shear tool will scream and chatter.
Have got to revise my ideas regarding how much stickout I can have on this lathe.
Have mounted it temporarily on an old Triton table saw bench - the slots allow me to easily clamp or shift the motor slightly when changing speeds.
Both chucks had awful chuck jaws, 3 jaw hooked at front by 0.010" and four jaw dreadfully bell mouthed. Was dreading learning how to do the grinding . Surprisingly, was able to hand file the 3 jaw chuck jaws back into service and it now holds things very well with no wobble or misalignment. And it might be quite easy and interesting to make new 4 jaw pieces, new ones would also be "soft Jaws"
The big motor works fine, the small motor needs a new speed control - replacement $480 for motor plus speed control from Sherline Australia, Looks like a dremel type motor or a small sewing machine motor with an appropriate mounting method might be a good substitute, I cannot spend $480 on something that tiny. Have got an Aldi multi speed tool that may do the job. Will have a play.
Bought a cheap laser tacho from BangGood - initially it was terrible then I figured out that it was due to random readings caused by uneven surface. Fixed that , used a texta to make a strip of paper uniformly matte black and put a piece of white tape on it, stuck it to the pulleys and then got rock steady readings. Checked it against known speeds on my Hercus Lathe and Rong Fu Mill spindle. See photo called Tacho.
Looking forward to learning what I can and cannot do on this lathe. Am aware of some amazing work displayed on internet websites done by these tiny lathes.
Bill
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15th Mar 2019, 06:54 PM #695Member: Blue and white apron brigade
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Why the two motors?
BTW for less than 1/4 the above you can buy a new 1/2HP 3Phase 4 pole motor
See https://cononmotor.com.au/product/0-...ase-415v-copy/
Then add a $100 FD and you'd be miles in front.
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15th Mar 2019, 07:51 PM #696Golden Member
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Why two motors
Bob,
Thanks for the tip. I like the idea of the motor/vfd you suggested - will keep for future reference and my mate up the road needs to do something like this for a 2nd hand Taig he bought.
These lathes come standard with a tiny 1/5HP 10,000 rpm motor that sits on a bracket on back side of the headstock. See attached photo (screenshot from Xynudu video). Initially I was keen to restore it to original configuration, but $480 scared me off.
The small motors may have been thought to be a bit underpowered hence the bigger one as an optional extra, and my bigger motor works just fine, 370 Watts.
The small motor might be useful to me when using the Drilling/Milling accessory.
https://www.sherline.com/product/305...illing-column/
At the moment am not in a hurry to fix the small motor maybe I can get a 3 phase tiny motor with VFD ? Will do some googling.
Probably just as easy to drill from the headstock onto a vertical milling attachment on the cross slide.
EDIT : Just saw this https://cononmotor.com.au/product/0-...-phase-415v-2/
BillLast edited by steamingbill; 15th Mar 2019 at 08:00 PM. Reason: Just saw this
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16th Mar 2019, 12:35 AM #697
Some enterprising person got into their reject parts bin when the Oz business was sold to the US, and ended up with enough to assemble about 25 complete Oz units, with all Aussie accessories including a mill column (as per the US milling machines) and sold them through a hobby shop. I was the unlucky purchaser of the 24th, and it is once POS re straight bed etc. It is currently in storage along with all my more worthy gear.
The reason I am commenting on this is that mine had the sewing machine motor without speed control. I put a small plastic electronics box on top and included a standard (at the time) 10A lamp dimmer in it as a speed controller. It worked fine but the motor stalled if it was set below about 50% due to the load from belt tension etc, the sewing machine motor is rated at about 120W input, maybe 90W output at full power, so there is not much to loose as you slow them down. I also set mine up to reverse the motor via a toggle switch in the same box. So getting speed control on the small motor may be a $30 hit rather than a $480 one.I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.
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16th Mar 2019, 02:45 AM #698
Hi Bill, Guys,
Re your comments about the shear tool, I use one if I'm after a particularly good finish or a bearing fit. I don't know if you have power traverse on your lathe, but I set mine for the slowest feed possible ! As you say you can take fractions of a thou off with ease. You may find that the cutting angle also affects the finish. I grind mine at about 35 degrees off vertical, leaning away from the chuck.
With regard to motors. Almost any small universal motor can be speed controlled using a light dimmer switch. I have several, one of which is a 10 amp one and I've used it to control the speed of a 180 volt 2.2 Kw treadmill motor quite successfully. At least I did until I discovered that the shaft was bent.
Anyway it looks like you have got yourself a nice little lathe there.Best Regards:
Baron J.
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16th Mar 2019, 05:19 AM #699Member: Blue and white apron brigade
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16th Mar 2019, 06:59 AM #700
Hi Bob,
I think you forgot the performance curves
Seriously though, I ran the motor without any load for a little while without any issues. I did monitor the voltage from the bridge but it never went above 220 volts at full speed. It was only whilst I was doing this that I noticed that it started to vibrate quite badly as the speed increased . Then when I measured the shaft run out, I discovered that it was bent. About 20 or so thou if I remember. Quite unsuitable for the project that I had in mind at the time.
The light dimmer control worked very well, and I thought that I had it cracked variable speed wise. No run away and a very smooth ramp up without blown fuses. 13 Amp in the plug. It probably would have been very different under load.Best Regards:
Baron J.
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16th Mar 2019, 10:33 AM #701Member: Blue and white apron brigade
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I agree their are fine on low loads. I've set up a number of HD (2400W) chinese dimmers for mates with routers and these seem to work fine on these power tools provided they are using smaller bits. One bloke even showed his to his wife and she tried it out on her cake mix beater and it worked so well I set one up for her as well.
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16th Mar 2019, 05:29 PM #702Golden Member
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Dimmer switches for mugs ?
If I google dimmer motor speed control I get to HERE
From the ads at the top of the search it looks like I can buy an already made gadget for between $20 and $50.
I did some further googling and got thoroughly confused with various folk disagreeing with eachother regarding whether or not dimmers are a good idea, or when they can/cannot be used.
Too much information and disagreement out there for an electrical novice like me to comprehend
Any good books or websites you can endorse as being a good place for me to start learning about this ?
One video I saw the chap simply cut the active line, inserted the dimmer on the active line and hooked it up to his motor.
I suspect its not that simple. Happy to be wrong.
After I understand things a bit better would be happy to buy a BangGood gadget for $30 and simply stick it on if thats possible.
BillLast edited by steamingbill; 16th Mar 2019 at 05:31 PM. Reason: Inserted last line.
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16th Mar 2019, 06:25 PM #703Member: Blue and white apron brigade
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They can be used on UNIVERSAL motors (eg power tools, cake mixers and hair dryers) but not on synchronous motors.
EG see Cheap Speed control for universal motors.
You won't get full power on anything other than max speed.
One video I saw the chap simply cut the active line, inserted the dimmer on the active line and hooked it up to his motor.
Screen Shot 2019-03-16 at 3.22.38 pm.png
After I understand things a bit better would be happy to buy a BangGood gadget for $30 and simply stick it on if thats possible.
If your load is light you may not need a fan so you can get them without for $6 https://www.ebay.com.au/itm/4000W-AC...d=282658437804
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16th Mar 2019, 08:19 PM #704
Hi Guys,
Just to dispel any confusion ! Universal type motors always have carbon brushes used to feed power to the armature, usually via the field coils. Either way they will run on AC or DC current. If you want to reverse the motor, the usual thing is to feed the motor DC and swap the feed connections. You normally cannot do this with a motor fed from AC, the direction of rotation is set by how the field coils are wired.
Motor Speed Control.jpg
There are two common scenarios for controlling the speed of a Universal type motor ! The most common is with a lamp dimmer unit simply placed in series with the motor. This method feeds the motor with a phase angled chopped AC voltage, the peak value of which varies with the phase angle.
The second method puts the motor inside a full wave bridge rectifier ! This method effectively doubles the amount of power available to the motor.
In either scenario the motor can easily be reversed simply by swapping the feed wires over.
Variations on these methods are very common on machines in which the speed can be adjusted, some of which have been previously mentioned.
Hope this helps to clarify speed control of Universal Motors.Best Regards:
Baron J.
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21st Mar 2019, 02:17 AM #705
Motor Speed Conrol
Hi Guys,
I know replying to my own post is not good, but I felt that I had to in this case.
This morning I was in one of the charity shops in town, just nosing about while the wife went shopping, or what ever she does when I'm not looking.
Anyway there was a box of electrical items on the floor waiting to be sorted through, and I spotted two interesting Items. The offer of a quid (pound), 0,50p each was accepted and I came away with these two Items. Both apparently brand new, since there were no scratches on the 1/4" amp tags, seemingly unused items.
20-03-2019-002.jpg 20-03-2019-003.JPG 20-03-2019-001.JPG
It turns out that they are a fully functional speed controller of some kind. Both work perfectly well when tried with an electric drill and a 2.2 Kw lawnmower motor. The two outer tags are connected to the brass case and the Triac is welded to it. Under that circular depression in the brass case. The middle tag is the feed to the motor. I'm assuming that the brass case is the live supply. The black shaft turns a 1M ohm potentiometer that alters the speed from zero to as fast as the motor can go. The printed data on the case says 6 Amps at 240 volts.
I'm going to put one of these things into a plastic box with a plug and socket on it so that I can just plug a universal motor driven device straight in and use it to control the speed.
Anyone know or have any idea what kind of device these might have been used with ? With the brass casing being live it must have been in some kind of enclosure.
Thanks all.Best Regards:
Baron J.