Gina

Have you thought about how you will access the outside of your back wall for painting or whatever? It looks very close to the fence or is that an optical illusion? HTH.

The roads shouldn't be so cluttered up with Grockles now the children have gone back to school.

SS definitely!!

Yes indeed, I was going to say that. Also, I tend to use good or best quality parts. Plus some parts are for my convenience such as the Duet3D WiFi control board. Not only WiFi but everything is controlled from a standard browser. No editing and uploading of firmware as in the Arduino MEGA plus RAMPS. It also makes the printer very quiet. The downside is the price which amounts to nigh on £150 by the time you add carriage and VAT to the basic price.

One day I might try and work out how much each of mine has cost. It's not easy as there are so many parts involved.

Yes, I'm afraid cheap 3D printers are an illusion. They are cheap for a reason!

Not postman but Amazon - a bunch of thermistors for 3D printers and a big book with large type as my eyes aren't what they used to be.

I'm afraid I can't advise on ready made printers as I have not bought one for several years and there have been vast developments since then. Having an engineering background, I build my own.

The cheapest and easiest to print plastic, PLA, is certainly not bendy as long as you use a decent thickness. There are bendy filaments if that's what you want though. Other advantages of PLA are that the fumes given off are not toxic and not very unpleasant (unlike some others which really need a fume cabinet with fume extraction to outdoors) and it is produced from natural vegetable chemicals and is biodegradable. Most other types are made from oil.

Glued very thin bits of aluminium sheet onto the left hand end to seal the ends of the horizontal holes and now tested the waterblock under full pumped water pressure and there are no leaks - not even the slightest dampness. The grub screws and pipe connectors were sealed with silicone sealant (as used for baths and other bathroom fittings and windows etc.). This photo shows how the waterblock is held in the extruder casing - the front has lugs which hold the neck piece firmly in position.

You'll enjoy Steve's book - I certainly have and found it very useful ??

Now to the heaterblock. The one shown above, 30mm high with two 60W heaters and a straight filament path worked alright but printing speed with a 2mm nozzle was limited to around 30mm/s. I wanted to print faster than this so Chriske and I did some "out of the box" thinking. It was his idea to try a folded filament path to provide a much longer melting distance. This would depend on whether the filament would be soft enough to turn a right-angle after just 20mm or so. I decided to make this type of heaterblock and see if it worked. First attempt was with one heater to test the principle - it worked but the heater was unable to provide enough heat to melt the filament at the speed the extruder was capable of, so I made a second with two heaters. That has proved to work well and the maximum printing speed has increased to 90mm/s - three times the previous best. Explaining a 3D object in a 2D medium isn't easy so I've taken three screenshots of the 3D drawing which I'm hoping will help to explain the construction. The first screenshot is a top view, showing the holes for the heaters each side near the top of the image. Very top are holes for the clamping screws, with a threaded part and clearance on top. Between the two heaters is the M6 threaded hole for the heatbreak. A hole nearly to the bottom of the block takes the filament down to a horizontal hole. This takes softened filament to the front of the block where a vertical hole takes it up to the top again (well almost). Here another horizontal hole takes the filament to the bottom left of the image (actually top left of block), connecting with another vertical hole taking the filament down again and ending in another M6 threaded hole to take the nozzle. M5 grub screws are used to seal the open ends of the holes where filament must not come out.

Well, that waterblock was alright for a while but the slightest movement caused the O rings to leak. After a while they would settle down and seal again. Trouble was, it took very little to cause a leak again so I've abandoned that and made a waterblock from aluminium. Here is a drawing of the waterblock in clear blue to show the inside features plus two photos. The brass parts are for attaching the water tubes and the top bit fits the E3D Titan Extruder. The larger M6 threaded part, bottom right, takes the heatbreak.

I use electric fencing though we did use some fixed standard stock fencing in the remote field (since sold).

My observatory build is pretty rough in places but it works and looks alright from the outside so IMO that's all that matters.

Sounds good.

Changing the gear ratios round isn't the answer - too many problems. Reducing the modulus also reduces gear size, reducing the tooth size and keeping the number of teeth. Going from mod 2.5 to mod 2 would reduce the gear sizes to 160mm and 120mm for the large gears and 16mm and 20mm approx. for the pinions. That's 80% but maybe 90% would be sufficient giving gear sizes of 180mm and 135mm, pinions of 18mm and 22.5mm. Mod 2.25.

I've been looking at where all the gears etc. will fit in, bearing in mind that the chain and weights have to go inside the trunk of the clock. It's going to be quite a tight fit particularly if I'm going to include a striking mechanism. Looks like chimes are going to be impractical. The difference between my clock and standard longcase clocks is that my gears are going side by side rather than one behind another and also being a lot bigger. Big gears make more of a statement as well as being more practical to 3D print. The main problem is the large minutes wheel with its 80 teeth and about 200mm diameter. An alternative would be to change the gear ratios round with 6:1 and 10:1 rather than the other way round. Since the intermediate gear will need redesigning anyway I can go for 10 teeth and 60 teeth on the minutes wheel, making it 150mm diameter. The problem with this is that the intermediate gear couldn't be larger than 150mm, making the pinion on the escape wheel just 15mm diameter, which is very small. I'm going to have to have a good think about this.

Printed a test moon globe - here are a couple of photos with a warm white LED bulb inside. The clock can have a cold white LED or maybe a combination of white and blue LEDs to improve the colour. This is with a 0.3mm layer height but I may reduce it for the proper print. I shall only need the front half for the clock as we never see the far side of the moon so might get away with something like 12-16 hours printing time. This was 16 hours for the full globe (except the bottom bit).

Heres a photo after printing a 20mm high test. Taken with early morning sunshine for illumination. This is actually white PLA so why it looks brown I don't know. May be better with a cold white LED.

Had another go at the moon globe, this time with white PLA and it looks very much better. I think this may work.

I thought that with my build!

Next I need to find the parts to make up the frame to hold the axles for the gears. Bearings for the escape wheel and probably the gear that drives it can be PTFE. The bearing for the anchor escapement could also be PTFE but I think I would favour a knife edge instead, for even less friction. I might reprint the gear that drives the escape wheel in Nylon for reduced friction. The pendulum is suspended on a spring steel strip as usual so little friction there.

Found some gears that seem to pretty much match this diagram though the escape wheel is off-centre and will need reprinting.

Earth Date 2018-09-05 - Looking at this project again having got fed up with 3D printer development, which has not been going as well as I would like. My Titan printer is working well (for the most part) and so is the Mini so I have production 3D printers in operation for making parts. The main thing now is trying to work out where I got to and finding the parts already made.