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Thread: Finally got myself a small mill!
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24th May 2018, 11:18 AM #16.
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It has been my pleasure Bob.
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24th May 2018, 08:01 PM #17Intermediate Member
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Might sound like a silly question. Where did you apply the heat? From inside with the door open or from the front of the arbor? Is the point of the heat to expand the metal of the part the houses the arbor or the loosen and dried up gunk? Going through the same thing right now but not having much luck.
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24th May 2018, 09:14 PM #18Member: Blue and white apron brigade
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For answer see other thread ie //metalworkforums.com/f189/t201...or#post1935320
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31st May 2018, 09:04 PM #19Member: Blue and white apron brigade
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I finally got around to spending a bit of time on the Hercus Mill.
I started by stripping out the electricals as I am going to run it from a VFD
The original RH outside of the electricals cabinet looked like this with 3 switches on teh outside and the contactors and 32V light transformer on the inside.
Sidebefore.jpg
Now the side looks like this.
The original door has been flipped upside down and a hinge has been added and a hole cut in the doorway for a 92mm 240V fan.
Its a ball bearing fan so it's nice and quiet.
It probably doesn't need a fan although I do plan on putting two VFDs inside the cabinet.
I will replace the 1/4" gutter bolt closure screws with something "knobbish" when I see something appropriate.
Sidecabinetdoor.jpg
Door opens to reveal space for 2 small VFDs.
The VFD shown is a 2HP Powtran 160, a compact full vector drive unit.
The space for the other one is for a smaller Powtran VFD for the coolant pump
The fan extracts warm air from the top of the cabinet thus drawing fresh air through the mesh. I will place some sort of a filter over that mesh as soon as I work out an simple way to do that.
I will add something to stop the door dropping completely downwards.
dooropen.jpg
The VFD and most of the wiring sit on a shelf that is on HD drawer runners so it all can be pulled out facilitating the wiring and servicing of the VFDs
drawerout.jpg
The Large Al VFD Brackets are held in place by a single M5 screw held down by a knurled nut.
This allows for the VFD to be quickly disconnected from the shelf and laid down on its back for even easier servicing.
VFDdown.jpg
I'm now working on a remote panel for the VFDs which will be attached to the LHS of the mill, near to where the light bracket is attached.
The panel will be housed in a recycled (die cast Al) box
The power for the VFDs is coming through the control panel but I temporarily attached mains power to the VFD so I could run the mill and i used it to cut some slots in the die cast Al box.
I learned my first lesson on "tightening things down firmly" when the box moved while cutting the slot out for the NV Switch. Fortunately is was not much and it is adequately covered by the switches outer border.
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1st Jun 2018, 01:25 PM #20.
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Neat Bob though you are making me nervous about the ventilation of the VFDs in the base of the No.1 How essential is the fan? My worry would be its ability to draw in grit laden air.
The tightening issue is something that needs to be experienced first hand. Check the parallelism of the jaws on your sub continental vice by clamping one of your newly acquired parallels between the jaws. You can easily establish if they are true or out of whack by trying to pull the parallel out. If they don't clamp evenly disaster awaits.
Bob.
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1st Jun 2018, 02:13 PM #21Member: Blue and white apron brigade
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If it was one VFD I would not bother with a fan. Even with two VFDs, 1 x 1.5kW VFD for the mill motor (which is only ~375W output) and 1 x 0.4kW VFD for the coolant pump motors (OP ~80W), its unlikely to be a problem unless the mill motor was run at close to full load for some tme. As I said I will pre-filter the air - if there is one thing I know about its air filtration - I have several filter media I am going to try including a roll of stuff I found (as usual) in a skip.
The tightening issue is something that needs to be experienced first hand. Check the parallelism of the jaws on your sub continental vice by clamping one of your newly acquired parallels between the jaws. You can easily establish if they are true or out of whack by trying to pull the parallel out. If they don't clamp evenly disaster awaits.
Thanks for the idea of testing the vice parallelism
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4th Jun 2018, 08:11 PM #22Member: Blue and white apron brigade
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Still phaffing about with the electricals for the mill.
Added a filter to the inside of the door.
Found some appropriate steel knobs on an old WW machine at the Mens shed that was being scrapped.
EDoor2.jpg
Took AB aesthetic advice and replaced 6 of the acorn nuts on the outside of the door with short CS screws.
The 3/16" acorn nut I added to the LHS is for the door stay.
Filter.jpg
The filter is some sort of carpet underlay I found in my trailer along with a pile of other rubbish when I went to pick it up from my sons place to go get the mill.
Stay.jpg
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6th Jun 2018, 10:03 PM #23Member: Blue and white apron brigade
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Some progress with the electrics.
First step was to make and install an Al flat bar mast (M).
I wanted the control panel to be where the light was so the mast allows for the light to be mounted higher up and out of the way
Box B is the control panel box - its an old Al die cast box I found in a skip.
Blue ethernet cable is for pump control
Grey is for Spindle control
10 way Ribbon cable is for remote mounting of VFD displays.
SideHercus.jpg
The Inner guts of the control box.
Switch S1 send power to the VFDs.
S2 is for the light - can be used with VFDs off.
Panelguts.jpg
On the first test run I could not get any signs of life on the VFD displays until it dawned on me that because the plugs in the ribbon cable were not a mirror image a cross-over cable would be needed. This one is made from 2 pairs of in line 5way plugs.
XoverCable.jpg
Control panel
The two pots are for fine and coarse speed control of the spindle.
S on/off controls the spindle
P on/off switches the pump.
Panel.jpg
It looks a bit crowded but if it starts to get too close I can mount the panel a bit further back
Wholemill.jpg
None of the panel controls are connected at the VFDs yet and I'm still waiting for the PI130 VFD for the pump to arrive.
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10th Jun 2018, 12:54 AM #24Member: Blue and white apron brigade
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Messing about with the coolant pump.
As I said in an earlier post its a 415V 3P pump and it runs on 240V 3P (albeit on lower power) but I wanted to see what sort of pressure it could generate on 240V without converting it to 240V. Finally got enough clean ATF to par-load the tank and measure the pump head. The oil reaches the lube point on the mill @ 45Hz but not a whole lot more comes out at 50Hz - sort of a medium-slow dribble.
Never mind, I thought I'll bump up to 60Hz but at 52.8 Hz the pump seems to lose grunt and slows down?
Apart from modifying the motor I guess I could lower the viscosity of the oil by adding some kero but it might not be enough especially as I have no taken any low temperatures into account. I 'll have a bit of a look tomorrow.
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10th Jun 2018, 06:26 PM #25Member: Blue and white apron brigade
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I decided to convert the coolant pump to 240V ∆. Was a bit tricky and reminded me of AB's tool and cutter grinder motor which as I think 1/30HP - the one is ~1/20 HP so in the same league. Wires as fine as hair.
Full WIP in the electronics section of the WW forum. I meant to put it in the MW forum electronics area but as the WW forum is where all my moto mods are thought I would post it there.
Tricky Y common point excavation
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12th Jun 2018, 05:34 PM #26Member: Blue and white apron brigade
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240V ∆ Conversion of coolant/lube pump completed and test run showed the following.
Oil now reaches the lube point on the mill with pump motor running at 38 Hz.
At 40 Hz the flow is marginally more than the unconverted pump motor @ 50Hz
IMG_3169.jpg
At 50Hz flow is quite good.
50Hz.jpg
60Hz - more than happy with that.
60Hz.jpg
I have had the pump up to 70Hz but flow does not change markedly above 65Hz so it's probably hitting some sort of impeller/viscosity limit.
I could now, as krisfarm did, change the ATF viscosity by adding a bit of kero but I think I'll stick with this for the mo.
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12th Jun 2018, 09:17 PM #27Member: Blue and white apron brigade
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I've develop bursitis on my right knee which has really slowed me down but I managed to stay upright long enough to complete the electrics for spindle motor and coolant/lube pump motor.
Here is everything wired up with the shelf fully extended out - yes it's a bit of a dogs breakfast but that's the benefit of hiding it all behind a cabinet.
The cables have to fairly loose otherwise the VFDs on the shelf cannot slide out
TwinVFDs.jpg
And with drawer tucked away.
tuckedawayVFDs.jpg
Tomorrow I'll start programming the VFDs. But now I have to get some ice onto that knee.
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