Member postings for Jelly

I already have an Adflow unit for welding, and a spare AX filter cartridge for it, so I would just need to get a headtop, but the 3M semi-disposable filter respirators are fine for short durations anyway.

This said I'm not actually using cellulose, I was originally going to but the specialised gel-coay etch primer I'm using requires the use of a xylene based basecoat paint, which in turn requires a high build clearcoat for protection.

It would have been way more work to take all the gel coat off and get back to bare fibreglass than it is to use a three paint system. The etch primer is weird stuff, and contains some really nasty volatile amines which allow it to soften and chemically bond with the surface of the resin.

I would definitely appreciate the speed of the 2K system, because all told I will have spent three days on this by the time it goes back on the truck, most of it waiting for paint to dry enough for a re-coat.

Unfortunately for the colour match I wanted no-one sells a commercial 2K paint so I would have had to buy it as pigment and mix epoxy, pigment and metal flake to match, which is getting in way too deep, I wasn't good at that kind of stuff even when I was still regularly laying up fibreglass in moulds.

The Basecoat is extremely thin and very awkward to spray compared to the primer, but I have managed to avoid any runs on areas which will show so far.

Initial results seem very promising though.

Edited By Jelly on 09/04/2023 12:16:37

I would guess the expense, I bought that tent for £30 in a partially broken state on eBay (it gets used a fortnight every two years at a festival I help organise and is held together with duct-tape and hope) so I don't really mind if it gets a bit painty or further damaged...

Brand new they're about £800, so a cheap and cheerful marquee makes more sense for the same purpose.

Has worked extremely well however.

Dipped my toe into the world of paint spraying, using a somewhat knackered tent as a temporary spraybooth.

I have long avoided it as being too complicated, but in fact it's probably far easier to achieve a good finish than brushing in a fraction of the time.

Going forward I think it will be my preferred method of painting anything which needs even a half decent finish, I may even be drawn into working with 2K paints.

My Z-Book has a 256Gb M2 SSD as the boot drive with most of my important software and in use files on it, and a 2Tb 5400 RPM SATA HDD for infrequently used programs and archived files...

Using anything on stored on the HDD feels like wading through treacle by comparison.

Despite being nearly a decade older, the Z-Book with the M2 works out faster than my work laptop which uses a SATA SSD for anything which relies on large amounts of stored data.

I like phosphoric acid as a rust remover, but it is fundamentally different to evaporust which is non-corrosive to steel/iron but breaks down rust via a redox reaction.

It's some very clever chemistry which being proprietary isn't well characterised, although I have a couple of theories about how they've accomplished it after playing about with trying to formulate something which would do the same thing, albeit with not as much success as the evaporust developer (removing rust is easy, the not corroding iron in an aqueous media no matter how long it's left is hard).

It appears things have improved somewhat in the current iteration then, as this definitely wasn't my experience of Denford's older machines (which credit to them are extremely well built, just with awful control units).

Ultimately if there's now independent and commercial support available for their products it does make them much less limited, and removes a lot of my objections.

I would still be a bit concerned about service support and planned obselecence though, as compared to a home workshop or school DT department setting, I would expect a machine in a Makerspace to get comparatively heavy (and sometimes clumsy) use, a bit like how hire cars and company vans get a very hard life compared to personal vehicles.

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I would also still agree with the initial thrust of David's argument that the specific model of mill proposed is a bit on the limited side though...

Moving up to the Denford VMC1300 (if the supplier is a sticking point, or an equivalent Haas, Syil or a secondhand industrial machine) would be an excellent "anchor tool" to draw in unwitting future volunteers members, which can really help a project like this get off the ground.

However without knowing the full scope of the councils budget and ambitions, we can't know if they haven't planned for other such "anchors" with their initial group of organisers which are seen as relevant to know local demand.

Edited By Jelly on 06/04/2023 17:55:16

If I was David I wouldn't worry too much about the local council's expectations (which can usually be "shaped" quite easily as long as you articulate things in a way which allow them to say they have met the objectives they've been set)...

It's ensuring that the first batch of members are aligned to the agreed interpretation and that as further members join, it remains clear and isn't subject to chinese whispers.

I suspect having council oversight will make that less painful than it would otherwise be for volunteers like David, but it's definitely something to go into with your eyes open.

Also maintaining control over storage of materials and projects (as well as "Projects" which anyone who has been a user of a shared workshop (commercial, community or otherwise) will know is a potential stumbling block.

TBH it's not really clear to me what the practical difference would be from the perspective of someone who is looking for one local to them.

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If you dig into it there's actually a total lack of clarity about what a Makerspace is because it's a novel term adopted by a bunch of different groups of people who all claim it for their own.

There's also a bunch of Makerspaces who are aligned with the "Hackspace movement" and aren't on the Government's list, but don't like the connotations of "Hack" so choose to use the Makerspace name instead.

If you dig deeper into it, quite a few of the "Makerspaces" on the gov.uk list would be described as "Fab Labs" by parts of "the maker movement" because it's controlled by an external organisation who are offering services/access for a fee rather than being a community (which also adds complexity around what legislation applies to the organisation).

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This actually raises a useful point for David to consider:

That lack of clarity over what a Makerspace is has previously lead to organisations going full "People's front of Judea Vs Judean people's front" and falling apart because there wasn't sufficient clarity and group consensus from the off about that exactly they wanted the organisation to be.

See also the list maintained by the Hackspace Foundation.

Hackspaces are fully independent non-profit entities which are constituted more like model engineering clubs, but with a far looser affiliation to the Hackspace Foundation than ME clubs tend to have to one of the Federations.

Facilities vary wildly as it's directly linked to members willingness and capacity to fund and volunteer, but the older and bigger ones are often impressively well equipped, and offer 24/7-365 access to members in good standing.

York Hackspace in Fulford has a regular open night on a Wednesday

Is this the makerspace in Mansfield/Kirkby-in-Ashfield by any chance?

Based on experience with a similar organisation, I would suggest staying away from the Denford CNC tools because they use proprietary control units which aren't one of the widely known industry standards, making it hard to generate G-Code other than with their proprietary and limited software. Meaning that even a homebrew solution with LinuxCNC or Mach3/Mach4 would actually be better supported and more usable.

The Organisation I was involved with was given a Denford CNC lathe by a university as it was judged to be too limited for teaching purposes, of the +800 members (of which a significant minority are professional machinists working with CNC every day) only about 10 have ever persisted enough to make it work for them, and only 2 have been able to use it to it's full potential rather than in the limited capacity the proprietary software allows.

It's likely been recommended as Denford have cornered the UK market in simplified CNC tools for educational use with secondary schools (ironic given the above from the Uni), although my 2 friends who are DT teachers also dislike them for similar reasons.

The circa £6k + VAT for a Micromill Pro would buy a decent condition Bridgeport Interact or the equivalent XYZ machine with a protrak clone, which has a much greater capacity, and would be highly capable as a CNC or Manual mill and offers conversational control which is a good bridge for people conversant with one approach to learn the other.

If the budget stretches a little further, then something like the Haas Mini Mill or VF1/VF2 would be an excellent and well supported full CNC machine which has been designed for usability and is well regarded as a machine for novices, they're around £14k new, but do come up cheaper in the used market periodically.

My experience of Makerspaces more widely is that the successful ones (London Hackspace, Nottingham Hackspace, Leeds Hackspace as examples) fully commit and offer their members access to full size tools which are sufficiently capable to make real-world parts in the widest range of materials possible, whilst those which cautiously buy small limited equipment struggle to attract and retain members beyond a small core group.

Which means that really it would be best to get the council to think in terms of "what would a Further Education College buy?", rather than "what would the purchasing group our secondary schools use would like to sell us?"...

In this vein, take a look at the virtual tour of the Engineering Campus of West Notts College, who have gone for Haas for their CNC teaching machines (scroll through to the "Engineering Workshop 2" in the tour).

Edited By Jelly on 06/04/2023 02:14:02

Successful rehomed the Trident-Pallas Horizontal Mill to a new owner, I wonder if I'm actually just running a machine tool rescue center and just don't realise it...

Like the Cats Protection League but for ancient metalworking equipment.

I have to say it looks kind of comically small on the trailer there, although was still bloody heavy to load (and unload) using a sack trolley.

Mine is actually branded as a "Trident" but after some careful examination, appears to be identical to a Pallas apart from the name cast into the door.

I would be unsurprised to learn that the castings for all four brands came from the same foundry, with minor modifications like the name on the door casting, not unlike the situation with chinese mini-lathes today where a number of manufacturers make similar products from the same source of castings, but machine and assemble those castings differently introducing small variations.

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It's remarkably well made for what it is really, despite being extremely basic...

Although the one time I did run it as a mill it became apparent that it needed to be, as with a side and face cutter mounted, it really will chew through material at a rate far exceeding what a (physically rather larger) modern vertical mini-mill could dream of.

Bearing in mind the hole you'd need being very close to the edge of the compound, I would suggest drilling a smaller diameter of hole and then turning the end of the pin down smaller with the lathe to suit the hole diameter.

The compound is almost certainly made of cast iron, and a sharp HSS drill will work well at a suitable speed.

Because of the location, I would consider the following:

• Fit the toolpost to the compound and get it in the exact position you want and use a 10mm transfer punch to mark the centre of the pin location.
• Take the toolpost and compound off the lathe and mount it on the drill press.
• Use a centre drill to locate the punch mark and start a very shallow hole.
• Drill a hole with a 5mm/6mm drill bit to around 6-8mm deep
• Without moving the part, use a 5mm/6mm ball-nose endmill to follow up, going about 1.5-2mm deeper (using endmills in a drill is not great practice, but as long as you're very gentle feeding and the drill has already removed most of the material it will work here, and definitely use a HSS endmill rather than carbide).
• Measure the true hole diameter with your calipers.
• Reassemble the lathe.

Having done that, you can move on to adapting the pin:

• Put the pin in the lathe and turn the bottom 10mm down to a diameter about 0.1-0.05mm bigger than the hole diameter you measured.
• take it out of the lathe and test fit it,
• if it doesn't slide in easily, put it back in the lathe and take a very fine cut of around 0.02mm then test again.
• Keep testing and taking small cuts until it slides in with only hand-pressure.
• Optionally, round off the bottom of the pin into a hemisphere in the lathe using a file or a form tool.

If you have an internal micrometer small enough for a 5 or 6mm hole (mine starts at 5mm, and anything smaller is a fortune), then you can avoid a lot of the test fitting by taking a more accurate measurement than the calipers would achieve and turning the pin down straight to that size.

The reason for suggesting using a ball-nose endmill rather than a reamer is to ensure the shape of the bottom of the hole is as rounded as possible, with no sharp corners to form a stress riser which could cause a crack to form later.

Edited By Jelly on 05/04/2023 15:11:55

I would agree on that based on the photo where you can see an oily witness mark from the pin.

That's down to implementation.

The recommendation for using VFD's for speed control I've had from ABB and others (when discussing pumping and material conveying applications) is thus:

• Purchase an "Inverter Duty" motor which is rated for a given power output (on a curve) over a given frequency range (this varies with vendor/design and includes options like 10-50Hz, 10-100Hz, 50-250Hz or even 40-400Hz for different types of constant torque and variable torque applications).
• You should base the motor selection based on it's rated Power at the RPM corresponding to the greatest highest power requirement.*
• Gear the motor drive so that your lowest required equipment speed is equivalent to your motors lowest rated frequency.
• If you need a very high gear reduction to achieve this use a 6 or 8 pole motor.
• Set the VFD parameters up so that it matches the frequency-power curve of the motor, accounting for the increased back EMF

They were very clear that you should not be running motors below their rated frequency.

Applying that to the use case here, a 40-400hz 4 pole motor with a fixed two stage 5:1 and 2:1 pulley reduction could give a speed range from say 24-2400rpm, which would be suitable for pretty much anything you might realistically drive in a MT2 drill spindle.

If you only do smaller work you might consider a different setup like buying a 50-250 Hz 2 pole with a 5:1 reduction to give 300-3000rpm.

*In our use case this would mean looking at the recommended metal removal rates for drills of various sizes in various materials, developing curves for power consumption and using those identify the point at which the highest power demand is and it's corresponding RPM, so you can match that to the motor's curve.

Edited By Jelly on 05/04/2023 12:34:33

Edited By Jelly on 05/04/2023 12:50:44

I wouldn't worry too much, those Multifix toolposts are horrendously expensive to buy toolholders for (I was extremely lucky to find holders for mine at a fraction of RRP) and your Dixon type toolpost is at least as rigid.

It wouldn't solve your knurling issue either because my Multifix does exactly the same thing if I'm knurling hard materials too enthusiastically without the locking mechanism engaged (my compound has a one-way spring detent for the OEM four-way toolpost which isn't entirely reliable at engaging due to being slightly misaligned with the corresponding hole in the Multifix).

I would say you have correctly identified that you need a locking mechanism between toolpost and compound, andin the first instance stripping it down to inspect is the best option.

If you find a locking mechanism or blind hole on the compound as designed by the manufacturer, I would suggest you modify the toolpost to use that if possible, just because it will be far easier to rectify any problems if the operation goes wrong.

If there isn't anything on the compound then drilling a blind hole to engage that pin is a widely accepted solution to deal with the issue of it rotating under heavy tool pressure, I would advise doing it with the toolpost in place on the compound to act as a guide, ideally with the assembly off the lathe and securely clamped down on a drill press where you can set the depth of hole to avoid breaking through.

I have gone for a second bite of the cherry vis-a-vis workshop activities and decided to have a good old fashioned panic about where the hell I'm going to put my new mill.

I hadn't fully considered quite how much room a 1982×2648mm [6'6"×8'8"] operating envelope really takes up until I went to lay it out this evening, so whilst there is a space available if I want the workshop to remain even vaguely ergonomic I am going to need to move everything around to accommodate it...

Edited By Jelly on 03/04/2023 20:57:15

Follow up post, the lathe has now found a new home.

The mill is reassembled but seeking a new owner still.

I should be clear that under the idea of "pay what you want" I would be entirely happy to let this go FOC to someone who will get good use out of it (I had always thought it ideal to pair with one of the GH Thomas small dividing heads for making gears and such, with the lever feed and all)...

Edited By Jelly on 03/04/2023 18:26:35

And got it fully reassembled in about 45 mins, most of which was spent messing with bearing clearances.