Retrofitting a 1986 Maho MH400E

And now for something a bit odd. I've fitted my Maho with a frog warmer! And no it doesn't have a problem with frogs. It's actually a humidity control system. As you may have seen the rear of my house is basically underground. The concrete roof has a garden on it. You can see from a previous post, on occasion it can look more like a submarine. In the lifting crane post you can just see the front of the house, which has window for its full length which faces the sun (north in the southern hemisphere). So i have a situation where the rear of my shed, through the glass work, faces a cool sandstone wall the is usually damp and stays around 18 degrees C all year round. I can pull damp air along between the glass and the wall to an air conditioner radiator yet to be fitted. Nice and environmentally friendly... eventually.
The awning on the front of the house shades the front rooms from sun in summer and allows it in in winter. Nice. So I currently balance the house temperature by having a set of small fans circulating house air though into the rear shed and back. There is also in water heating tubing throughout the concrete floor including the shed. But here is the downside of all underground houses. If you take warm air from the house and circulate it to that colder zone near the underground part, the absolute amount of moisture stays the same but the relative humidity goes up. And of course dew forms when that cooler air gets to the dew point. In Sydney that can happen even in summer on a high humidity day. So that glass wall sometimes gets wet with dew and puddles of water on the sills. Being right next to it, the radiant temperature of the cold glass can form dew in the contactor cabinet. Expletive deleted here!
So I've fitted this relative humidity controller. I've just set it to give 70% relative humidity and it turns on 40 Watts of the "frog heating" elements. It's currently runs the heating pads about 1/4 of the time, so not expensive. 70% set point gives about 5 degrees C distance from the saturation line on the psychometric chart. I've fitted some 15mm rigid foam to the inside of the cabinet doors and to the inside roof of it to reduce the heat loss which makes a noticeable difference to the on off ratio. When the machine runs this system simply gets overwhelmed by the cooling fans, but it's not really worth switching it off. The elements look like sheets of Mylar with resistive material fused between them. I've simply slipped them up the gap between the contactor mounting panel and the cabinet wall. The mounting panel standoffs give a 15mm gap for them. Perfect place for them. The humidity sensor is on the cabinet roof.
For a few bob extra I got the one with WiFi so now I can check if my "frogs" are doing okay from anywhere in the world!
Note on the side of the mill photo, the air exit mesh as mentioned in a previous post. It now has a Mylar flap over it that stops the humidity system losing warmth. It swings out a bit when the cooling fans run.

David

Here is the coolant pump after a lot of paint stripping and painting. Note: the plastic impeller just unscrews, but left hand thread.
I replaced the ball bearings in the motor with new double sealed ones.
The pump shaft I linished on the lathe.
There was a coolant thrower on the shaft but it was just a rubber grommet that someone put there. I replaced it with a Vee ring seal. I smoothed the face of the pump casing so the lip of the seal can run on it. I've dry run it mounted on the tank. It runs so smooth I had to put my finger on the shaft to tell if it was running. If anyone knows where I can buy a small 415 Volt plug and socket for a 300 Watt motor so I can shorten the very long cable to it I'd like to hear.
The tank I had sand blasted with a bunch of other stuff. it was a nasty mess inside. It's leak testing in the photo, with a bit of detergent to lower the surface tension for leaks. It has a new level indicator as the old one was smashed. The cover plates blanking the holes for it were my first CNC part off the Maho.
There is a new linear grommet around the perimeter for the lid to sit on.
That little bucket on the side of it by the sink tap goes into the foot of the mill and catches the coolant returning to the tank. It means the tank must be put in that position which is awkward. I've placed some big plastic slides underneath it so I can slide it out for cleaning. It needed raising anyway as the whole mill is sitting up on rubber mounting pads and the side bucket wouldn't fit otherwise.
David

This is near the end of the saga. I thought I'd add a little on the lube oil mess these machines make. I'm using oil lamp wicks to help direct the bulk of the lost lube from the various slides etc.
Starting with the little moat at the base of the Z jacking screw: Much of the knee's lost oil ends up in the moat. On mine is unevenly cast and ends up with puddles of lube oil in it. To drain that oil, I've simply put a wick of the type used by old oil lamps in it. The end of it goes down the drain hole in the casting where it is caught in an old sandwich tray. I threaded that drain hole and put a bit of brass tubing down below for fear that the wick might get caught in the Z axis drive belt as you see. The tray is actually a bit full. I'd prefer that the wick wasn't touching the oil, not that it's important. The thing that makes it work is the head drop down the wick to that point. It will actually cause concave menisci in the wick laying in the moat from that suction head. So the puddles get sucked empty, not dry unfortunately.
Along the X axis on mine is a rather hopeless piece of sheet metal that is pretending to catch oil running down the face from the slide way above. I'll probably improve that at some point, but currently I've simply used gasket cement to seal against the casting face. It has drain hole at each end back into the casting but the oil from them drops on the shed floor out of other casting holes. It's not clear in the photo but I've  threaded the cross drillings in them and attached plastic tubing. The tubing arcs around back into the casting and drips onto the shield spring cover of the Z axis jack screw. But again, I've put a wick in them. In this case there is a bootlace that runs a bit along the tough formed by the bend in the sheet metal oil catcher, into it's drain port and some distance down the plastic tube. The same capillary action as above sucks the oil from the trough and deposits it down the tube. I can say that there is a lot of oiling on that spring shield. Cheap and cheerful and easy to do. Noticeably saves mopping the oil off the floor, but it's not a magician.
Also,unless you machine is very stable and level, that sheet metal trough will flood at one end. My whole machine is on rubber mounts so it can flood.

David