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Member postings for Jelly

Here is a list of all the postings Jelly has made in our forums. Click on a thread name to jump to the thread.

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Thread: Making work equipment.
30/03/2017 21:48:53
Dave,
Thankfully there is a series of policies in place regards the requirement for CE marking of equipment, and a separate policy which is linked to the Management of Change policy for determining if new CE marking is required when equipment or repaired or adapted.

We may also have a policy specifically for equipment which logically seems that it should be CE marked, but actually is not in scope, and thus legally cannot be, and the compiling and holding of a Technical File and conformity assessments to satisfy PUWER98 requirements, something I believe has been done at least once before.

I suspect the major issue is that it's an unusual situation, in an area of both dense and consequential legislation. I'd be inclined to start by saying no and move to asking questions later too if I was in the shoes of our H&S team.
30/03/2017 21:00:29
Nathan,
That's interesting stuff, AFAIK Godwin now trade as a brand of Xylem Water Solutions, who bought them to add pumps to their offering.

I'm aware of a number of firms offering similar C.o.t.s. vacuum systems, but mostly at a small scale for laboratory purposes, if Bendix produce versions which can evacuate piping systems at a sensible rate (I'm instinctively imagining 3" or 4" nominal size), that could be of interest as a replacement.


Nick,
I suspect we'll keep seeing it as both British products will be sold to the EU and European ones to Britain.

We did invent and popularise the idea of a conformity marking in the form of the BSI Kitemark after all, so it would be unsurprising if we continue using our own good idea.
Thread: Tools you Treasure
30/03/2017 19:46:20
I'm fortunate to have a great many...

To the great displeasure of my parents, my paternal grandfather gave me a small ball pein hammer at the age of 3, it remains in regular use and reminds me fondly of him every time i go to pick it up, the first among equals of a treasured bunch of tools.

He subsequently gave me a small set of joinery tools, including a small "footprint" fine toothed dovetail saw, which is my go-to saw for fine work of all kinds.

My maternal grandfather gifted me my great grandfather's carving tools and moulding planes when i was in my teens, and later after I left university, also gave me the bulk of his engineering tools, micrometers and inspection equipment; he still enquires after it from time to time, and seems particularly happy that I'm able to keep utilising them to their full potential.

There is also an unusual looking King Dick adjustable spanner which has no story to it, but simply happens to be better made than any other adjustable I've ever seen, almost as if some previous owner had taken the time to closely fit the parts.

Thread: Making work equipment.
30/03/2017 19:23:01
Have any of you in the past made bits of equipment for your employer; and if so have you had any issues or experiences to share from doing so?

I recently built an air powered Vacuum ejector ("Venturi Pump") for a specific task, after a discussion with one of my managers about having been working on (steam) injectors the previous weekend on seeing it worked they deemed fit to repay my costs via expenses.

Subsequently, the H&S Dept first asked if it was CE marked (by a curious co-incidence, a Venturi falls outside the 6 possible EU directives you might expect it to be covered by, and therefore is not eligible for CE marking), and subsequently conclude that this 'home made' equipment cannot be used, as the firm would have the product liability for it in the event of an accident.

I left it at that, as as H&S are ultimately doing their jobs correctly to protect the company and its employees. However it has been raised that the business routinely manufactures and adapts equipment in house (as any firm with a decent team of fitters would), and this is no different, so I may yet be asked to go back and make a case for this bit of kit.

I have all the drawings, calculations and details to affirm that it was suitably designed and manufactured (I originally foresaw having to CE mark it, so needed to compile a technical file to issue the declaration of conformity), so it shouldn't be a huge issue to confirm it as being at least as safe as any commercial off the shelf model, but In all honesty I'd perfectly happy to chalk this up to experience and maintain cordial terms with the H&S team.
Thread: Precision layout & machining?
28/10/2016 18:06:40
By and large referential measuring using a datum point and accurate machine scales will take you where you need to be.

I'd point out that accuracy is not an end in itself, but a property which work should possess only as much as is required, if you're drilling a bolt circle, then it's likely to be sufficiently inaccurate due to the process to make laying out to ? a thou somewhat pointless, and if it's being bored after drilling to achieve that accuracy why worry, the referential method used to position the boring head will make it irrelevant.

Achieving repeatability of tolerances to ?0.1thou (i.e. 2.54μm) or even ?0.5 thou is the realm of second-op work, holes need to be bored or reamed, cylinders and mating surfaces ground, lapped, scraped or planed and so on.

As has been hinted at earlier in the thread, the best thing you can do is to think about the design intent of the piece and which dimensions are critical and require that extra mile in terms of accuracy.
Thread: Apprentice Piece - Turning
14/10/2016 01:56:54
Thanks to everyone who has come forward with suggestions, I really appreciate it. The screwdriver is perhaps the most promising thus far.



Secondly as it seems to be of great importance that I explain this further, some more background, I've been involuntarily volunteered to organise the sessions because the chap doing it previously is project managing an extension to our facilities (and we're all volunteers) and as a result of that simply hasn't been able to do them for a while hence backing up to 40 and needing to recruit additional bodies, as we're overwhelmed; this isn't something I'm particularly relishing doing, but it's very much necessary and ideally should end up as a self-sustaining process.

The people wishing to learn/get inducted are all have all requested an induction because they want to use a lathe, for myriad reasons from repairing model diesel engines to modifying solenoid valves for gas-puffer fire-art installations...

There's no unifying background other than a desire to make, it doesn't matter to the organisation, nor to Me what they want to do with it, so long as they do it safely and with an understanding of the limitations of machine.

The reason for using a Myford is simple, that's the lathe they will have access to for the next 6-12 months, until the extension is complete allowing us to start using the Warco, and possibly sell the Myford... I'm a bit vexed by the insistence of some posters that a Super 7 is unsafe, the basic Myford design is not PUWER98 compliant without upgrading with a modern NVR equipped DOL Starter and Interlocks on the guards... But that's rather distinct from being inherently unsafe.

It is being organised along formal lines, in that we're a large organisation (490+ members, if anyone would like to know specifics, PM me), and have identified that we need to ensure that users of machine tools are at a minimum standard of competence and that we have a record of the same; a big driver for the formalisation is that we need to develop a process for induction which will standalone without the support of its creators.



John thanks for saying that, as you mention it, it is rather tempting to just disappear as the forum is not coming across as particularly welcoming or 'Can-Do' in this instance... That would be somewhat rash though.
13/10/2016 13:34:06
So a couple of things I've failed to adequately explain.

The purpose it to allow them to use the lathe safely and independently without damaging it through inappropriate use; it's being organised on behalf of a community run workshop facility which offers members the chance to develop skills and use machines it's wholly impractical for them to otherwise access.

All the inductees will be adults, usually with a hands on practical background, but usually in art, "design/craft" or electronics rather than engineering.

Up to now we've struggled greatly with inducting people who had no engineering background, as we tried to teach everything in one hit, resulting in long sessions, poor retention of knowledge and an inability to effectively deal with the volume of people.

It's very much our ethos to provide info and mentoring on safe use, but to expect functional learning (that is developing the skills to make a thing) to be wholly self directed.



We will be running a group classroom session or e-learning module to familiarise people with basic engineering concepts (drawings, conventions, names), the theoritical bit of machining (Speeds & Feeds, Chip theory, relative hardness of materials etc.) And safety aspects.

The practical teaching will be 1:1, with each inductee having as much time as required within reason, but we'd like to get it to within 2 hours just for everyone's sanity, and to allow us to get through whole group in good time (I'm reasonably expecting to manage a maximum of 10-15 a month between all 5 volunteers).



We're debating whether to have a group practical session making hand fitted parts first before the mill and lathe practicals, but it's additional volunteer time which is like gold dust.



It's quite likely we'll also use the production of the "Apprentice Piece" as a truncated induction process for new members with prior experience, as if they can take a piece of material and a drawing, then appropriately produce the finished product under loose supervision, we have no need to worry.

13/10/2016 00:20:59
I've been asked to help organise the induction of around 40 people for safe use of lathes and milling machines.

There will be a team of 4-6 volunteers delivering this, so we need to standardise our approach somewhat, part of this is developing a standard "Apprentice Piece", due to various constraints I'm struggling to work out what this could be, as ideally it would be something useful or purposeful; but consulting with the volunteers who did craft apprenticeships, they're all equally stumped as they started by turning non-functional test-pieces.

The induction is only required to teach safe practice, and normal operation, with precision and advanced techniques being something users are required to develop off their own back.

I'm looking for a standalone piece of which could be completed by a novice under instruction in 1-2 hours. I have been asked to include the following operations: Facing, Plain Turning, Drilling, Boring, Parting/Grooving, Taper Turning (using top slide only).

Has anyone got any suggestions?

(We'll be using a Myford Super seven for teaching, but may wish to migrate to using a Warco GH1440 in time).
Thread: (pseudo)NC Hydraulic Surface Grinder
07/10/2016 14:04:40
Thanks Carl that's quite useful to know, it's looking like to be affordable I'll need to use an arduino based controller to handle inputting the settings and displayi g them via seven-segment displays... The price per I/O for PLC's being too high to run the I/O heavy displays and 16 key input.

(I don't really want to dispense with the PLC altogether as native support for gray-code, 24v outputs, analogue outputs and relays for 240vac are very useful features that wouldn't be available nearly so easily from an arduino).

Thread: Hi from a-not-so-model engineer
05/10/2016 15:10:37
@KWIL: I'm trying to re-purposing a manual surface grinder into an NC Hydraulic one. To complicate matters, it was bought from a guy who had made it himself by re-purposing a horizontal mill. See the thread in the Homebrew CNC section for quite possibly more detail than can sustain your interest.

@Nick_G: It's more that I don't want to give a false impression that I am, as if I talk about work at some point I might easily leave that impression unwittingly.
05/10/2016 12:12:06
Hi All,

I've joined after several years of lurking, as I thought the forum might have some insight into a problem I had, and maybe I'd be able to give some insights back in due course too.

I'm not sure I count as a model engineer, as I don't seem to work on anything at a model scale, most of my personal projects being either machine tools or toolmaking.

I "teach" wood-machining and some metalwork as part of a community organisation, and am also active with a heritage railway, but tend to do more fitters type work than machining/engineering there as I'm a recent volunteer (trust being something which is earned and all).

I worked for a large sawmilling concern all through uni, and got to learn a good bit in their toolroom and fitting shop (between turns sweeping, lifting and carrying), then went to work first in the Oil and then Waste industries as a Chemist, meaning I've been around and involved with engineering projects professionally for my whole working life; but am not actually an "Engineer".
Thread: (pseudo)NC Hydraulic Surface Grinder
04/10/2016 16:14:08
LabVIEW looks and sounds ideal, but looking at their I/O hardware, made my wallet make some funny hissing noises and snap shut...

I think need to fully document the intended process flow and then start building up specifics until I really understand where the big challenges are, and probably end up buying LabVIEW because the savings in time are enough to justify the cost of getting an interface board.

Unless of course I've misunderstood and I can use the software to directly access the PLC's I/O via serial.
04/10/2016 12:08:49
You're entirely correct, an existing hydraulic grinder would be a lot easier to start from and I had an opportunity to get a Norton grinder, which simply needed the hydraulic cylinder reconditioned, and some new piping...

The issue that stopped me is twofold, this ision loan in a communal workshop by agreement with the other users, so to take it back to a mill and bring in a purpose built for see would need quite a lot of non-engineering effort to build consensus (and I don't quite have it in me to do all that right now). Secondly we're tight on both space and floor load (with a Bridgeport Mill, Myford Super 7, Warco Engine Lathe, jig borer, Another small lather, Denford Novaturn, CNC mill, donkey saw, Vertical and horizontal bandsaws, plus three welders and a Layout table, all on a concrete slab support ed by RSJ's over a basement we're really wary of additional floor loading), so the aim is to make the Pallas conversion both smaller and lighter than a conventional grinder would be,accepting that it involves possibly sacrificing some accuracy when using the full 18" of the chuck.
04/10/2016 00:41:25
I'm just starting to look at a project to convert a manually operated "Surface Grinder" into a hydraulic one with a numerical control system, and would value the experience and ideas of others as I'm not 100% how to accomplish some of the details.

Basically the machine is a small Pallas/Trident horizontal mill, on which the bearings and spindle were improved by a previous owner to allow it to run at speeds sufficient for grinding, along with fitting a high speed motor. The current feed is via a rack for the X axis and Acme Screw for Y&Z axes, which is suboptimal for my needs, but suited the man who re-manufactured it very well.

My basic plan is to start by replacing the t-slotted table designed for milling, with a purpose built carriage consisting of a cast iron dovetailed slideway to which a welded metal drip tray and an assembly to allow quick-change between mounting of both an 18"*6" magnetic chuck and a dedicated machine vice. This would not be driven by the rack, but by a hydraulic ram attached to the saddle, rather than using limit switches to reverse the valves during operation, I was planning to have a linear scale output to a PLC (likely a 32-IO Mitsubishi unit I have sitting about) allowing control of where the machine begins and ends it's stroke to minimise wasted time during the cycle.

This leaves me with enough IO's left over to also automatically actuate the other two axes (y&z), using the same linear scale self measurement system with either more hydraulics, or via servos acting on a leadscrew.

I have a couple of stumbling blocks, firstly actuating the knee by leadscrew gives a issue as to both replacement of the crude acme with a much higher tolerance ball screw in order to realise the kind of accuracy a surface grinder should deliver, and then the issue of developing sufficient torque to move it... But equally, using a ram as an actuator, opens up scope for it to move slightly during operation if the system isn't perfectly sealed in order to resist any downward force, that's after accurately quantifying the behaviour of the cylinder and valves to allow very precise movement initially

The second is how to set and display the parameters of the machine, a shared numeric keypad, parameters selection switch and LCD for each is logical, but would take up quite a lot of IO's; the alternative approach is to have a separate logic controller to deal with the input of settings, which then simply outputs the setting for each to the PLC.

The Y-axis would need to remain on a leadscrew due to space constraints, and is likely to be sufficiently precise retaining the existing acme, torque is also less of an issue, compared to raising the knee.

In an ideal world, I'm aiming to finish up building a system where I can chuck a part; set the final dimension to grind to, Y-axis & z-axis step distance, x-axis limit postions and feed-speed; touch it off using a jog-function; press run and leave it to cycle.
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