Stub Mandrel

I always stick my STL files on an SD card. Fewer cables the better.

26 minutes ago, Thalestris24 said:

What does 'Home All' do that I wouldn't want it to?

If you haven't adjusted the stops yet, it can plunge various bits into other bits.

Setup instructions should let you get the stops set right and then you can home the head with impunity.

A striking difference between the bars was in their stiffness. Bar 3 was much more flexible, presumably this was because of the direction of the fill being along the length of the bar, whereas in the other bars the fill effectively divided it into many short compact cells rather than a few long ones.

Increasing the density of fill from 20% to 50%, fig. 5.35, both stiffened the bar and resulted in a significant increase in strength.

Thread Strength

Very simple tests were performed to see how strong screw threads are. Test pieces were printed with close fitting threads in them, using 40% fill, a reasonable amount to use for structural parts.  The threads were not ‘tidied up’ in any way and were tight but it was not difficult to insert the screw, fig. 5.36.

Ordinary cap screws were fitted and given a total of ten turns – the head of the screw was NOT tightened up against the test block. The pull-out strength of the screw was them tested using the same spring balance as for the fracture tests, this limited the maximum force to 35kgf (75lbf). The test was then repeated with the screw wound out to five turns of engagement.

Table 5.3 – Thread Strength

The M6 test was done with a lever giving 10:1 advantage, 240Kgf is nearly a quarter of a ton...

9 hours ago, Chriske said:

Before I decided(that was years ago) which filament I was going to use for most of my parts I did tests on solid parts. It was a completely different test I also did to test what colour would be best to use in sunny conditions).  Anyway that test-part was 100x20x10mm, I made 5 of these parts each all with different infill and a few different materials. All parts had 3 perimeters. It took me almost 2 days to test all these different materials/infills.  ABS(I never use it myself). but did add that in my test because my friend Marc asked me to.
Half of the length of that test-part was clamped on my workbench, the other half was hanging free above the floor. Hanging on that part above the floor there was a bucket that I filled with brass, lead,...  The most promising infill (for PLA) was 'Line infill' at 40%. After about 30kg that small part started to bend. It needed 55 kg before it eventually cracked. To be clear, that bucket was not hanging close to my workbench, but at the very tip of that part.

 

I did some similar tests on 1x10mm bars.

The setup for a test

Please bear in mind that these were all based on single samples, except test 1 which was done twice, giving similar results.

Tests 1 to 3 were performed PLA test bars, printed with 0.2mm layers, a shell thickness of 0.8mm (using a 0.4mm nozzle), a top/bottom thickness of 0.56mm and a fill density of 20%. Test 4 used a bar with 40% fill.

Table 5.2 - Test Results

30 minutes ago, Chriske said:

Most (almost all) beginners underestimate the strength of printed parts.

Absolutely right, I printed a guitar effects box with the lid hinged on two M3 screws. It happily takes my full 13 stones standing on it.

31 minutes ago, Stub Mandrel said:

How do I let Sharpcap know I've renewed?

Just setting up and it tells me licence expired but I renewed on 12 September.

 

OK, I've found a new licence text in an email on my laptop.

For some reason Outlook seems to have blocked it on my desktop.

Working now!

How do I let Sharpcap know I've renewed?

Just setting up and it tells me licence expired but I renewed on 12 September.

I think I will make a PLA flower pot. That shoudl be the best possible test of how long it can survive in adverse conditions.

I would have NO worries about its lifetime if allowed to dry if it gets wet and away from constant exposure to sunlight.

On 12/10/2019 at 17:01, Alan White said:

154/5 mm but I may yet have use I am sorry to say,
Depends on the way I take things forward.
 

Let me know if you change your mind, thanks.

46 minutes ago, Alan White said:

Well my well worked postal operative delivered this morning.
Purchases from eBay out of curiosity more than need.

A pair of OOUK 6" Rings, to see how big a VX tube really looks like,
glad I did as notably smaller than a SW150p.
Best bit is my curiosity didn't cost a lot either.
 

What's the ID of those? If it suits and your really don't actually want them, I may be able to use them!

13 hours ago, Chriske said:

190°C....😱

1 hour ago, Chriske said:

Funny, so everyone has it's own formula to work with...

I wouldn't even think of printing @ 200C. My steppers would stall..!

Maybe because I use low print speeds?

Crikey, I've come down to 200C for PLA. No loss of layer adhesion and less ooze.

12 hours ago, PeterW said:

Now Jedi  I am Jawa.

 

 

 

Let me correct that for you 🙂

5 minutes ago, Gina said:

260°C

Yeek!

For PETG I presume?

The most satisfying thing about 3D printing is the 'crack' when the print self-releases from the borosilicate glass half an hour after the bed stops heating. Sadly I'm often too impatient to wait...

7 minutes ago, 62Marc said:

Thanks for the info. Are you able to tell me what other adapters you used to make this all work please.

I purchase the scope but I'm struggling to find the correct adapters.

 

Thanks Marc

Hi Marc, I'm afraid it's a home-made scope that uses the Skywatcher lens cell. I just made it with a  2" eyepiece fitting and the tube length to suit the OVO field flattener which adds about 55mm (from memory) and doesn't change the focal length. The T-canon adaptor screws straight on to the Ovo flattener.

I also made a low-profile 2" to 1.25" adaptor to allow me to use my eyepieces with either a diagonal or a straight 2" extension tube.

It was a bit of a nightmare working out what overall tube length, focus tube length and focuser travel would allow me to use all my kit without vignetting!

These photos may help:

Visual setup without 2" extension - focuses on terrestrial targets but not stars!

Imaging setup, I do need to add a finder !

Not very astro, but at least they are black... to help me play Ace of Spades at full speed!

15 hours ago, Chriske said:

Indeed , I even print my own plectrums...😉

Yes Chris, but you'd print your own breakfast cereal if you could! 🙂

16 hours ago, Gina said:

hotend cooler fan was running slowly

Peel off sticker, apply one tiny drop of mineral oil (e.g. sewing machine oil) to bushed bearing, replace sticker. Usually a permanent and long-term solution.

I need three washers 1/8" thick  for spacing switches in a guitar A/B box. Has taken just minutes to design them and get them printing.

3D printers are great for simple things not just complex ones!

This is good. I've often seen detail in a locally equalised image that I haven't been able to 'layer' in without spoiling the overall image.

I've got a problem though - I can't past into the layer mask for some reason? Even with the mask selected pasting creates a new layer.

How do I do this?

I ran off five prototypes of the shell for the cooled mono cam I printed. Impractical to do by post, let alone the cost!

3 hours ago, Fieldsy said:

A little light reading

That's 'dark' reading. 'Making Every Photon Count' is 'light' reading...

On Wednesday evening I had a first try of my Optolong L-enhance filter with my ED66 and modified, cooled Canon 450D.

This is one of the relatively 'new' tri-band filters that actually has two pass bands that encompass Hb & OIII at the overlap of blue and green and Ha in the red. Broader than narrowband filters, they still exclude most of the visible spectrum including all the main light pollution lines.

Unfortunately I was shooting almost straight up and a large dust bunny or two fell onto the sensor, moving between some frames making elimination with flats impossible. There was also a tilt in the imaging train giving poor stars AND PHD2 stopped talking to my guide scope a few times which also impacted the star shapes with long subs. Add some poor framing and relatively few subs and the resulting images are not really the fairest test of the filter but I have learned a few things.

I used super pixel mode so there was no bleed through of data between colours. I did little more than stretch in FITS liberator, to PS for a background balance and another stretch then denoise in PS or Astra.

1 - the images are easy to process using 'super pixel mode', balancing the background generally gives white stars. This gives a very pure, deep red Ha signal.

2 - The filter is very powerful at removing light pollution, normally my 300s subs would be washed out with skyglow. I could easily go to 10 minutes, except brightest stars would blow out.

3 - Blue and Green were, as expected, very similar with slight bleed through of the brightest patches of Ha.

4 - In targets with a lot of OIII, this comes out very well in a blue-green colour (Veil).

5  - It accentuates Ha very nicely on the red channel.

6 - It reduces stars, but not as much as a narrowband Ha filter.

7 - where there is a blue reflection nebula, this didin't really come out at all, just a fainter Ha signal, nothing in blue or green (NGC7822).

8 - where there is are secondary OIII signal I expected to get, nothing strong appeared although the Ha was very good (Heart nebula).

9 - I am guessing this will work very well for planetary nebulas and targets like the Rosette where elements of the ordinary OIII signal are clear even in an OSC image.

10 You could use this as a powerful anti-pollution filter for things like clusters, but don't expect to get lovely star colours.

Here are the example pics, blame my impatient settup and lack of monitoring rather than the filter for the poor results. You can see a few patches where I have tried to clone stamp the dust bunnies out and a few spots where I didn't bother...

Veil, 30x300s:

NGC7288, 14 x 300s

Heart, 16 x 300s :