Woody's Workshop – Page 14 – Keeping the Grey Matter active

March 23, 2023March 23, 2023

One Hundred Subscribers

I didn’t see that coming and fibre in France

When I installed Gravitec it was more out of curiosity than anything else. Did people read any of my waffle or was it just a freaky high bounce rate ?

While this number is just a drop in the ocean on YouTube sites it’s nice to know that people still read things and for some weird reason must enjoy my Yorkshire sense of humour and my engineering inquisitiveness.

If you are one of the Hundred – thank you !

Other things …. we are currently in France (hence the lack of posts). We had an offer we couldn’t refuse from our service provider SFR to swap out our ADSL copper based connection for a fibre-to-house replacement. The ADSL dribbled along at around 9Mbps which was more than enough for Fusion 360 to connect and for Netflix to keep us entertained in the evenings.

The house sits around 60m from the roadside telecom pit and is connected via an underground duct. I fully expected the duct to be blocked but the engineers successfully used the ADSL copper to pull the fibre through.

Not quite so simple in the house.

The external duct rises in the utility room and then branches via internal buried ducts to various telephone points around the house. The copper was solidly stuck in the one duct we needed so a Plan B was needed. After 3 hours of drilling holes in walls, floors and pipework trunking we finally got the fibre upstairs into the office.

The fibre is clocking a fairly symmetrical 800Mbps according to Okla which is staggering. Fusion is a bit quicker to load and general web activity seems a bit quicker but not 10 times quicker. Downloads are pretty quick though. If we had a house full of teenagers we would probably appreciate the increased bandwidth but we are long past that scenario – well that is until the grandchildren get online…….

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March 11, 2023March 11, 2023

3D Thin Wall Printing Experiences

Probably An Inconclusive Ramble

Some while ago I was asked to 3D print the component parts of a 1200mm wingspan glider. The design STL files are available as a paid download from the SoarKraft website.

The first problem this created was that my Sindoh 3DWOX had insufficient Z height for the 200mm high print sections. This was a thinly disguised excuse to upgrade my 3D printer to a Qidi ifast. This has proved to be a good decision and I am very impressed by the Qidi and the quality of the print results that it generally produces.

I now need to qualify that statement because I have struggled (and also learned a lot) trying to print thin wall prints for the glider parts.

The Qidi comes with a slicer that is a skinned version of Cura. I struggled to get good thin wall results. The main problem being transparency effects in the printed surfaces immediately following internal bulkheads within the wing design. I mentally envisaged this as the extruder being unable to start pumping filament fast enough following the bulkhead transition. You can see this along the inner curved line on the image below. There are very fine threads of PLA bridging the gaps.

I am also a subscriber to Simplify3D. Their website has a help article on Thin Wall printing and a recommendation that the Thin Wall Behaviour can be improved under the Advanced/Thin Wall Behaviour by selecting Allow Single Wall Extrusions for both internal and external walls. Playing with these options led to good prints that met the SoarKraft recommended weight. I need to do more investigation on the other options in the two Thin Wall drop down boxes but here is an image of two examples.

I asked Qidi if there was a similar fix in their slicer. They sent me a revised config file that did fix the problem but led to a significant increase in weight on the finished print.

The problem has also been beneficial in making me realise how important the slicer simulation was as a tool (as can be seen above). It allows you to see what is likely to happen with each change to the configuration print settings. Obvious but not always investigated.

The other discovery was that neither slicer (Qidi or S3D) are able to import STEP files which does seem a bit strange. STEP files are more accurate than STL files and STEPs are easier to modify in CAD programmes.

Sorry this is not a radical post but does show that 3D printing is not just ‘click and go’. The other comment is that there are so many options to change in a slicer config that I don’t think I will every get to grips with their individual impact on the print.

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February 19, 2023February 19, 2023

Parting Off on the Lathe

That old Chestnut …. Again

Go onto any home workshop forum and I am sure you will find a number of threads on the fractious subject of parting off on the lathe. It is a perennial topic that everyone has their sometimes not so humble opinions on. It seems to be the machinists equivalent to the search for the Holy Grail.

If you have a bulky rock stable mass for your lathe the problem is easier to solve. Rigidity rules when it comes to parting off. If you are less privileged on funds or workshop space you are more likely to have a Myford equivalent machine. The problem will then get magnified simply because there is not so much stability in the machine structure.

I have tried various parting tool configurations and I have to be honest I get a severe case of ‘squeaky bum time’ when faced with parting off steel. Brass and ally I can cope with but steel usually makes me wimp out and rush for the hacksaw.

My parting weapon of choice is a hand graver. This is appropriate for small diameters and using a graver is very educational. You can feel how the cut is progressing and you can feel how the cutting action changes as you change the angle of attack. It is a lovely craftsman’s tool and for clockmaking, in various geometries, is indispensable.

For larger diameter parting I have progressed through HSS front cutting, insert front cutting, Hemmingway kit rear cutting and now the latest variant – a simple insert tool holder rear cutting.

My parting collection – graver, HSS, front insert, Hemmingway and the new rear insert

To be fair the insert front cutting does work for brass and ally but on claggy ally the tool would often dig in and can jam the chuck no matter how much lubrication I use. This I assume is because front cutting leads to a digging in action whereas rear cutting throws the tool outward from the cutting groove.

The Hemmingway kit was a thoroughly enjoyable experience to build and it looks brilliant but the blades seem too prone to flexing. It is a real shame given how nice the finished tool looks. (Yes, I do accept that it might be something to do with my construction). So nice as it looks I tend to have little universal confidence in it.

So what is my latest parting panacea ?

I have mounted a standard, universally available, insert blade parting tool (SPB326) on the side of an old rear mounting post that originally came as part of a knurling tool. The tool clamping on the post has a sliding curved pressure support surface which allows tool height variations. I fixed a 12mm square steel clamping block on the rear of the parting blade with 2 x M5 cap head screws and clamped this in the mounting post.

I did a few facing actions on some brass to get the centre line correct and then began trial partings on brass and ally. It worked like a dream. Encouraged by this I moved onto a piece of 10mm silver steel (drill rod). Plenty of cutting oil was applied and apart from the initial engagement chatter it just cut beautifully. Lovely snails of swarf, no SBT reaction, no hacksaw needed.

Alright the blade and the insert are wider than ideal (3mm SP300) but this probably adds to the rigidity of the setup. A consequence will be that I will be wasting more metal in the cutting action but at last I seem to have a tool and recipe that I trust to work.

Well, for the time being anyway.

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January 29, 2023January 29, 2023

Adding Colour Coding to Fusion 360 Assemblies

How did I not know about this Fusion 360 facility ?

I was watching a YouTube video on Fusion 360 joints by Garin Gardiner. I couldn’t help but notice that he had colours on his assembly listing and time line. My interest was really perked…..

A quick search revealed that this is a standard but maybe not so obvious Fusion 360 feature. Go to the Inspect drop down menu and then Display Component Colours. Magic (albeit it can be a bit garish ..) but it really helps you to see what part or function is with what. If you start to feel a bit nauseous you just have to use Shift+N to toggle it ON and OFF.

Here is my recent Mark Presling clamp in Technicolor. (OK the colours could be better chosen ..).

It’s funny how sad engineers get all excited about such simple things……

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January 28, 2023January 28, 2023

3D Printed Mark Presling Clamping System

A PLA version of Preso’s versatile clamping system

Sometimes I think I am way out of touch when I suddenly find a new interesting YouTube maker site that had gone completely under my radar. Mark Presling is based in Australia and has some interesting projects and ideas on his YouTube vlog. My thanks go to Peter in Croatia for pointing me in Mark’s direction.

Mark’s latest post (Jan ’23) focussed on a work hold down clamping system using a variant of a ClickSpring eccentric screw and block concept. This looked quite interesting and was timely with my experiments with the Gack clamping idea.

I’m still in France, slightly idle but with Fusion 360 as ever close to hand. Mark’s post does not precisely detail the dimensions but I got a rough feel for proportions and modelled my interpretation of his clamp idea in Fusion. To give the eccentric screw clamp holding strength I embedded a M8 nut. The brass clamping block would remain the same as in Mark’s design and for clarity is not shown on the images below.

I sent some graphics and a STEP file off to Mark for his thoughts and we both agreed that a PLA or PETG version would work and probably be a simple low cost source for hold downs on many CNC router tables. Mark mentioned this in Part 2 of his video post.

Variants could be quickly made for different geometries to suit the work in progress. Like my Gack 3D print, the clamps would not stand up to serious full on metal CNC grunt milling but router table based profiling would be fine. The advantage a 3D printed clamp is that cutter dings when hitting the plastic would not do any damage to the tool. (I realise that none of us ever do that anyway ….).

In the ZIP file below there is a STEP and STL file of my interpretation of the clamp and also the Fusion 360 file for those wanting to play further.

3D mark presling clamp with embedded nut Download

I won’t be able to print the idea myself until I get home. I think it will need a vertical print to avoid the need for support material.

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