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Thursday, 17 May 2018

Another Vice Handle

 Last year I bought this homemade vice from a treasure shop:

I've used it, many, many times, more than I thought I would, so I was upset when the handle fell off. The original handle was just a nail, and I think the fastening method was a kink:

So, I made a better handle, well, one that didn't rely on a kink to not fall out:

I may attempt something better than a couple of nuts on the end, but they work. (And the diameter of the rod is a bit too small for an M5 thread). Let's see how long it doesn't fall out...

Thursday, 19 April 2018

An Arduino Case

A friend is working on an Arduino based project and wanted a case for the Arduino Uno and an LCD shield. He pointed me at this case:

A couple of printing sessions later (it took about an hour for the top and bottom halves, and 20mins or so for six buttons) and we have a case for the electronics:

As cases go it is nice to hold as it is curved, and fits together pretty well with the clips holding the top to the bottom. I'd prefer the case was screwed together, but there's no provision for that. the butons will need trimming I think, but after that it should work pretty well.
I used natural PLA (faberdashery) and that is transparent-ish and so all the Arduino LEDs shine through the case, giving a colourful effect.

More Maslow

The Maslow has been used quite a bit recently, and there have been a couple of problems. The chain was still jumping so I checked on the forum and found that another user had put the nylon chain guides (which I don't use any more as I have 3D printed some) close to the sprocket to stop the chain riding up on the sprocket teeth and then jumping. So I did the same:

This stopped the chain jumping completely. I haven't had a single jump since I did this. Unfortunately I did then have the chain fail to leave the sprocket correctly and it wrapped itself round the sprocket:

This isn't good, probably worse than a chain jump actually, as it can damage the machine. I checked to forum again and found that a weight hanging off the chain would probably help here, so I dangled a couple of power tools off the chains and that problem has gone away.

I then managed to cut all the remaining chair legs that I need to complete the set of six chairs I am working on. (I'm sitting on chair number two as I type this...).

Monday, 9 April 2018

Sometimes Things Don't Go Right

The chairs I've been making recently have four curved bars across the back. I've been cutting them on the Maslow. They look like this when they are finished:

I cut them with a router set to about 60mm depth and a toolpath that runs up and down the concave side taking off 2mm at a time. It then runs back and forth across the conves side taking off 2mm at a time. I hold the blanks to the Maslow base using a couple of 70mm screws. This is fine, except that on the latest part I was cutting the screws came loose, I think because the vibration of the routing and pressure of the tool was wearing the holes in the base. It's made of chipboard and the screws just got loose. Once the part started moving, the router made a hell of a noise and did this to the workpiece

The bit has ripped the wood apart.
I'm now going to try to use some 6mm studding through the workpiece and see if that lasts longer than the screw method. I only have seven more to do I think, so hopefully it will stand up for that long. I need a new blank now too...

Thursday, 29 March 2018

Aargh! The End Has Fallen Off. Again

Years ago I bought a vice that I have used a lot since. Unfortunately it came with a handle that has two round ends pressed on it:

 The problem with the handle is that the ends have a habit of falling off:

 After an end fell off for about the fifth time I finally got fed up enough to build another handle. The first attempt using some 12mm bolts failed as the material is just too nasty when machining it. You can just about turn the outside down, but drilling and tapping is impossible.  I used one of the chair legs that I chopped up with my bolt cutters to make a new handle:

The ends are turned aluminium held on with M6 cap head screws. If they fall off I can put them back on easily, and maybe use thread lock. So far so good, and it looks better too.

Wednesday, 28 February 2018

The £500 Dirty Photo

 I've been attempting to stitch together sets of photos from die shots for ages. I've managed about three so far, one of which was a big one. The latest attempt has been a failure on every computer I have, and each failure has taken hours in some cases, even overnight. The computers I have are mainly second hand and none of them are very modern or powerful.

Having a definite job to do I decided to buy a more powerful machine to do it on. So I spent £500 or so on a new (ok second hand) machine.
The result is a 386MB TIF file. I can't really post all of it here, so I've got a scaled down version:

This is an 8Mb version of the file. It's about 2000 pixels on a side, which is considerably smaller than the 10000 pixels on a side that the full image uses. The zoom that is possible on the full image is much greater than this scaled down version.
Unfortunately there's some dirt on these photos, which I'm not very worried about as I can retake some or all of the photos and rerun the panorama generation. The dirt is in the middle of the ROM so not the best place it could have ended up.

So there we have it, I spent £500 to get a dirty photograph.

Tuesday, 27 February 2018

Rainwater Harvesting Pump Controller Problem

Our rainwater harvesting system uses a pump and that pump is controlled by a, well, controller. This has worked fine for years, but about six months ago it gave a fault and I had to press the reset button to get it going again. It then ran for several months, but about four weeks ago it tripped again, and then it tripped many times.

The controller is a controlmatic E, I believe and it has a PCB inside which performs all the functions. From the symptoms I thought it might be an electrolytic capacitor problem as the frequency of occurrance is increasing. I took the PCB out and tested the electrolytic capacitors and found that they were fine. I then took the power supply dropper capacitor out and tested that and it did not look fine. I replaced it with a parts bin capacitor and the controller ran for a few days with no faults. I bought some new capacitors as I didn't want to leave a parts bin component across he mains, even though it seemed to solve the problem. It was also slightly wrong in value. I put a new capacitor in the PCB when they arrived and the controller has run ever since with no faults.

I have a couple of videos about it here: