Wednesday, 27 April 2016

The dangers of Teflon Tape

Thread tape, Plumbers tape, whatever you want to call it. You may have seen it used on hose fittings to help keep fluid inside. What many people don't know and can cause quite major problems is that you must be very careful about how it is applied. I recently replaced the shower rose in our bathroom so I will use that as an example here.

These are pictures of the old fitting and the wall fixture. It's a little difficult to see but the tape has been cut off the end of the thread and has gotten into the pipe and is partially blocking flow. In a shower this is not much of an issue, however when I used thread tape to seal up the transmission cooler hoses on the Jeep I had it could've caused some quite major problems if pieces had come loose.

These are the bits that I pulled from both the shower head and the wall fitting. Could be bad.
This is how I've been taught to apply this tape. Yes I know it's pink not white but it's all that I found around the house.
You need to wrap the tape so that when the fitting screws in it tights, not undoes the tape. On a standard right hand thread this means going clockwise around the thread. Another, lesser known trick is to feed the roll of tape in such a way that you can maintain even tension. If you look at the above picture you can see that the roll is away from the pipe. This means that I can ensure there is enough tension on there to pull the tape down into the threads and make for a good seal.

I usually do 2 or 3 wraps, but this depends on the depth and sharpness of the threads. Putting too much on will make it hard to screw the fitting together and can cause bits to be cut off and carried into the flow. To finish applying the tape I just pull quite hard on the tape while keeping it as if I just wanted to increase the tension of the wraps. This will stretch the tape until it tears and will leave it nice and neat.
If you find that you've wound the tape the wrong way when you start to screw the fitting together then simply unwind the tape and start again in the other direction.

Here we are, a new water saving shower head that will hopefully start to save us some money. A fairly easy thing to do for the average homeowner and over the course of a number of years can make quite a considerable difference.

I hope you find this useful at some point and if you've got any other ideas on how to apply plumbing tape please share below in the comments.


Monday, 25 April 2016

Amazing what a few coats of paint can do

Finally more progress has been made on the Fireball. We originally saw it here. About a year ago when I went for a drive up to Queensland and came back with the Fireball on the back of a borrowed trailer.
More recently we saw me getting a trailer of my own for it here.
Well, it now has nearly enough paint and varnish on it that we can splash soon again. My brother has put a few coats on the bottom and between us to date we have put 2 coats of paint in the cockpit and 2 coats of varnish on the deck. With the varnish on it started to look quite special, particularly remembering what it did look like before we started to repaint.

Below are some photos of the work in progress.

Just started sanding the deck. Not a very fun job I must say.
This is where I stopped for dinner. We didn't get a chance to start again until the next morning because the pain in the cockpit was still a bit wet in a few spots and we were hoping to keep most of the sanding dust out of the paint. You can see the whole deck except for the bits around the cockpit have been sanded and are pretty well ready for varnish.
This is the beginning of the light board that will sit on the back of the trailer to hold the number plate and lights. Nathan made it from a scrap piece of timber left over from repairing the verandah at their house. We ended up painting it to match the cockpit as we already had the paint out and being an exterior house paint it should handle being out in the weather.
All ready to go, wiped down with a damp rag then time to apply. We put the paint in the cockpit together then while that was starting to dry I put the varnish on. This was easier for 1 person to do because we only had one tin of varnish.

And here is the finished product after 2 coats. It was still a bit damp here so looks shinyer than it will once finished. But it certainly gives a nice look to the timber. It will probably need another coat or 2 as before we put this one on there were still some checks and weathered bits of timber that had soaked up all they could and were dry again.

So far on the 2 coats we have used probably a hair more than half of the tin we bought of varnish.

Hopefully the next update will start with a picture of the boat in the water with all sails drawing well. But we'll see. There are still a few bits a pieces that need to be done on the trailer first.


Tuesday, 19 April 2016

The Lathe still works

So I have finally got everything in place to use my CNC Lathe. To test it I ran it in manual mode. I stuck with the default settings of 80 mm/min, 0.25mm X incremental feed & 0.1mm Z incremental feed. I had a play with the spindle speed just to see what would give the best finish. There didn't seem to be much difference but I was just using a pretty soft piece of some kind of plastic.

This was all I did, the spindle is quite loud so I didn't want to be running this too late. I'm not quite sure what kind of plastic this was but I did get a fair few pieces of what seems to be Delrin that I will be experimenting with once I work out how to hold them as the chuck doesn't open far enough to hold them.

This machine is fairly old and is controlled from a 486 running windows 95. Not the world's oldest machine. But fairly old. The interface is all DOS based so to improve startup time I have disabled the windows GUI entirely and just boot into DOS. The interface, while definitely classic it isn't too hard to use or hard on the eyes, which can be a problem with some of these older user interfaces.

I shot a video of me machining this piece with my phone sitting on top of the safety shield. During the video you can hear the different pitches as I adjust the speed of the motor to see if that would change the finish. Watching the video and also while using the machine there is a lot of backlash evident in the Z axis so I will try to work out what is causing that and hopefully remedy it.

With this now working I should be able to power the spindle for the mill from the accessory port on the control box for the lathe. This will give me a chance to fully test and even start using it to make parts.

I have the manuals for this lathe so I will probably put together a program that will allow me to turn down the Delrin blanks so I can mount the securely in the better chuck. But we'll see about that.


Tuesday, 12 April 2016

A bit of fun, What's inside a Hard Disk Drive?

One of my relatives who recently got a computer upgrade had the old Hard Drive from the old machine and was concerned that there could be some sensitive data on it still. So, being the helpful young man I am I volunteered to destroy any data that might be hiding in there still.

This is where we start, It's an older IDE drive that I could probably use in one of my machines, but I have given in to the SATA cables and now I have a very hard time justifying why I should be keeping a drive that needs a ribbon cable, so I won't.

These are what hold the top on. These are just a normal Torx T8 screw. If you buy a small toolkit from Jaycar or many other electronics hobby stores you will probably find it includes some of these.

There's a sneaky one here hiding under the label. Make sure you unscrew it because otherwise no matter how hard you try, that top isn't coming off.

Once all the screws are out just prise around the edges with a screwdriver or another fairly thin tool.

The top should come off fairly easily after that, if not look for more screws under the label. (Ask me how I know.) If you look closely you can see there is a bead of some kind of semi flexible sealant around the edge of the lid. This is to keep air and more importantly dust out. These drives are assembled in a cleanroom type environment as any particles can significantly reduce the life and reliability of these.
Some drives do have a vent in them. Those that do always have some kind of filter over the vent to keep contamination out of the drive. The vent is required as during operation the internals of the drive change temperature. This causes the air inside to expand and it needs somewhere to go, otherwise it may damage the case.

Here we can see the interesting parts of the drive. The big silver disk is the platter where the data is actually stored. The metal arm that is pointing to near the center of the platter is the read/write head. The very end of it floats on an air bearing when the drive comes up to speed. If the air bearing fails for whatever reason the head can crash into the platter which can cause scratches and other damage.

This is a short video I put together of me destroying this Hard Disk. Don't watch if you have strong Hard Drive sympathies.

For anyone who doesn't want to load the video this is what the top of the platter looked like after machining it with a screwdriver bit.

I don't think anything is going to be recovered from this drive. But to be sure I'm going to be keeping a magnet on top of it and moving it occasionally, just to be sure.

If there's anything else you want to see inside and/or tortured like this drop a not in the comments and we'll see what I can do.


Friday, 8 April 2016

Don't let fear stop you

Sometimes we come across projects or sub projects that we don't want to take on because we are worried what others might think, if it's safe, if others will think it's safe, if it's too expensive. The problem is that when we let these fears and concerns govern what we allow ourselves to do then we end up not accomplishing anything near what we are capable of.

This is something that I have struggled with on various projects over the years, is it safe? What will others think of me doing it? Whatever the case may be. On the instances when I have put these fears into their place by stopping and working out just what the impact will be, then after putting into place safety controls I have always found these projects to be worthwhile. This one today is one of them. Here was my problem:
The controller for the CNC Lathe runs on 110V not the 240V that comes from the walls here. When I got the machines I had a few cords that would connect them to a transformer box  so they could be used with a 240V wall supply. Unfortunately I have lost said cables and to be able to run the Lathe I need to get 110V to it. Bugger.

This is where fear came into it. From the time I have started playing with electronics there has always been an unspoken rule that you just don't have anything to do with line voltage as a hobbyist. This is a very safe rule. However in this situation it would've stopped me from being able to run the lathe again unless I found the power cord (Unlikely). So after taking stock of the risks (electrocution) and working out controls (unplug and leave for a while to let any charge dissipate, test to make sure nothing is shorted to the case before re-connecting) I realized that this could be fixed safely.

And here's the finished product. I can now use a normal power cord like I would use for a computer to power the lathe with 110V.

That's where the scaryness happens. The transformer is potted in epoxy so that's all quite solid.

Looks like I'm not the only one who chain drills and doesn't fully clean up the edges. I had to take off some of the peaks before the new socket would go on.

Testing all of the connections. I'm using an old analog multimeter on ohm reading to check for shorts. It does still work, certainly well enough to show a short circuit.

That's all for today, the next post will be my 100th post on this blog so I am working on something cool for that so stay tuned.

And remember, don't let your fears tell you that something can't be done. There's always a safe way.


Monday, 4 April 2016

CNC Mill Moves, With evidence

The mill is running again, in it's new spot inside the house so I should be able to get to work on it a bit more often. This is where it is now, on the new desk with my laptop beside it running the controls
I had the lab power supply out to see if I could run the spindle off it. However even with the knob for current all the way up it was still getting limited so I think that's going to be a no-go. The good news is that I can still run it from the accessories port on the Lathe control box because I haven't gutted it yet.
It's a little bit dirty but not too bad and with the shield shut then there shouldn't be any issues with bits getting into the rest of the room which is good considering this is above my servers.

Here's the interface I am using for now. I'm hoping to get Machineface/Cetus/mkwrapper working so I can use any computer to control this, but for now I'm connecting with a VNC connection because mkwrapper doesn't seem to like being run in such a way as it can be accessed from outside that computer.

Finally, here is a short video I took while I was making sure everything still worked. I still need to set the maximum speed and tune the acceleration for each of the axies but I will get to that eventually. You can hear that when it's set right it's nice and smooth. But otherwise it sounds like somethings grinding.


Friday, 1 April 2016

Lake Mac Heritage Festival

Over easter the family took a trip up to Toronto to have a look at the Lake Mac Heritage Festival. This is something we have been planning to do for the last few years but finally managed to get there.

It was nice to be able to slow down and just have a look around at all the different things on show. Mostly there were boats but there were some cars and vintage farm engines that held our interest for a while as well.

Below is a set of photos that my lovely girlfriend took while I was getting distracted by all the shiny bits.