Purchase proposal — sturdy metal bench in metalwork

[mikeh]

Proposal Type:
Medium

Proposer:
Mike Hindley – metal

Description:
A sturdy metal workbench, to be situated in the middle of the metal workshop where the current flimsy shelving is. The bench will be made of clamp-together metal tubing, as is commonly seen on metal handrails, etc.

We will buy the tubing and clamps, then affix hard-wearing coated plywood for a top and shelf underneath. A rough sketch of the design:

The top would include a stainless sink (from FB marketplace), so people can work on engines and have the oil drain down the sink into a can underneath. We will also look to fit a reinforced metal plate in one corner to act as a medium-duty anvil/smashing plate.

It would be cheaper to buy the steel for a frame and weld it together ourselves, but once you add the cost of welding consumables, plus the huge effort involved (probably 2 people for a whole day), the bolt-together design seems more attractive.

PLUS - the bolt-together system means we can change it down the line, if required. And very quickly.

Proposed Purchase:
We will get the metal from themetalstore.co.uk and the plywood from www.emergerecycling.co.uk/touchwood/ — a local wood upcycling company.

Costs do fluctuate, but I predict a total cost of £300 for this. It could be less. This is based on calculations from 10/02/23.

Proposed Installation:
It will be delivered in pieces and required bolting together. I imagine it will take about 2 hours, involving 2 people, but a team of 4 would be even better.

Budget:
£250

Will there be an ongoing consumables cost?
No

Funding type:
Fully funded by Hackspace

Health & Safety
N/A

---

Supporters
Micro Proposal <£50 - 2 Board Members and 2 Members
Small Proposal < £150 - 2 Board Members and 5 Members
Medium Proposal < £500 - Majority of Board Members and 10 general members
Large Proposal > £500 - consult the board before gathering membership support, a strict board majority must be achieved. Large proposals can only be approved at members meetings with majority support from the members present. Proxy votes can be used.

Supporting Board Members:

1. Joe
2. Frank

Supporting Members: (delete number as appropriate)

1. Mike Hindley
2. Mark D
3. Guy P
4. Kevin W
5. Jim R
6. Peter R
7. Richard W
8. Bob
9. Stephen
10. Samuel M

[Josephxtian]

Heya Mike,

This seems like a great idea to me. I can’t quite read your drawing as the lighting isn’t great.

Standard size scaffolding is 48.3mm diameter, this stuff is really expensive new but can be picked up pretty dirt cheap second hand - anywhere from £0.50-2 per foot. It’s much more sturdy than the handrail stuff. Most scaffolding companies have plenty lying around they’re happy to sell off, and i imagine we don’t really care if it’s shiny and clean as it’s just going to get covered in oil anyway. Going direct to metal suppliers is likely to be many times more expensive than this route.

How many ft of scaff are you looking for total? I actually have a load at my parents house that I might be happy to sell to the space for £1/ft. It’d need cutting to size but the bandsaw shouldn’t have any trouble with that at all. Then you’d just need to buy the corners.

Out of interest how is the top being fitted to the pipes? Wondering whether having say a 9mm plywood top with a 12mm mdf sacrificial top screwed to it that can be replaced every couple of years by just undoing 4 screws would be beneficial?

Last suggestion would be putting the 4 tied together legs on braked scaff castors. Then you’d unlock the 4 wheels, lift the far two legs manually and you can move the bench around the metal room as needed.

It’d be worth clarifying where the existing bench thing in metalwork is going, but either way, you have my +1 support.

[mikeh]

Cheers Joe. Don’t worry about the markings on the drawing. It’s just the shape that is important.

Cheers for the offer of tube. We’d need approx. 38ft of tube (let’s call it 40) so @£1/ft that gives us £40 for the tube. Current cost for 42mm tube (which I currently specced) was £90 so that’s a big saving. The 48mm clamps will cost extra — £1-2 in most cases, and there’s a lot of them, so it ends up being a fairly slight saving overall.

The top is fitted to the pipes using this clamp:

Emerge do a full sheet of 18mm coated ply for £25 (we think) so it’s cheap enough to replace, and tougher than MDF against spills.

Castors are an option, definitely, at about £40 ea, if you’re happy to approve that? You could get away with two, perhaps.

The current blue shelving that’s currently serving as the bench could well end up behind the doors where the Atlas lathe currently is. Richard wants it to be a CNC lathe, so its eventual home could be the CNC room.

[Josephxtian]

Understood about the increase cost of connections. You may find in future when if comes to expanding the table 48mm tube is easier to find bits for though, equally maybe I’m wrong. There’s also someone on gumtree doing scaff poles for 50p/ft, so that would half the cost again, but would need someone to drive 40 mins from the hackspace to pick them up.

The wheels are a set, so it’s about £10 a wheel. I found these ones with a higher weight rating if people are gonna be hitting stuff on them.

Understood about changing surfaces. Was sure how fiddly it would be, but those connectors look sturdy.

[Marcus6275]

+1

I’m not familiar with scaffolding systems other than knowing there are many different types out there that aren’t all compatible. If getting the tubing is that cheap though and its the right size for the larger fittings then it would be better in the long run as it will mainly be the tube that we’d have to buy again if/when we want to make changes.

Castors might be useful, would depend on how often we expect this workbench to be moved around. I’m assuming that it would normally be anchoring to the floor with some of these: Square Base Plate - F131

[mikeh]

My initial thought was to have it free standing with plastic caps at the bottom of the legs. To be discussed. I think the overall weight of the table will stop it moving anywhere.

So we have three options of mobility:

1. wheels
2. legs not attached to floor
3. legs attached to floor

[guywpowell]

+1 sounds like a good idea to me. If you are planning to use scaffolding poles check the material. I picked up a pole when we had scaffolding round the house and it seemed too light to be steel, and it didn’t rust; aluminium? Still, it was strong enlightening to hold lots of material and labourers, and not rusting would be good.

[mikeh]

I’ve just realised thee’s two different costs on there! Should be £300.

My thought was that the pole would be steel, but you can def get aluminium scaffold. It’s used in things like mobile towers, I believe.

[Fnhalluk]

+1 board

[KWelton]

+1

Let’s do it!

K.

[Omniatus]

+1

Having used this stuff before, great idea.

[peterdroberts]

+1 And just to reply to earlier point, the emerge boards are £17.50 and I have two at home if you want to assess suitability

[mikeh]

I trust your judgment. Would you say the 18mm is suitable for a general purpose bench? Or would we need two, probably just screwed together?

[peterdroberts]

I think 18mm is fine. If you need more it’s probably work more appropriate for an anvil.

EDIT: Read requirements and you’re planning to work on engines. Will have to do calculations (which you can also do using The Sagulator – WoodBin). The ex-amazon flooring from emerge is ideal for oily work because it’s already coated but not sure on the material’s heat resistance.

Also do you have a hoist? Engines are pretty damn heavy.

[Omniatus]

I do still have a large sized trolly available with a nearly 10mm thick steel top, wheels at one end, handle at the other that’s about 1m X 2m. Stands around 1m high, maybe a little more.

Originally intended as a welding bench for weldy, but could be repurposed?

[peterdroberts]

You may as well do 2x18mm. 300kg (2L engine weight) on a 2ft span of 18mm would flex more than that calculator recommends. I don’t think anyone should be working on 300kg engines in hackspace and this calculation is inaccurate because it’s additionally supported at the edges. However the extra board is £17.50 and the calculator has it then reaching the same level of flex at 2500kg. This seems reasonably cost effective for the table to be way stiffer.

[peterdroberts]

I haven’t done static mechanics for years but scanning sites now it seems the deflection of a rectangular beam is proportional to 1/(width x height ^3) so doubling the number of plywood sheets octuples the bending resistance so yeah you may as well

[Josephxtian]

If it’s fixed down intelligently as well, it’s also that replaceable top surface i mentioned previously.

On a tangent about your calculator Peter, the deflection of a material is mainly a factor of its span and it’s thickness. So if you double the thickness you multiply the allowable load by 8. If you double the span, you reduce the allowable load by 16.

[peterdroberts]

I’m glad you confirmed my 8x conclusion JC. I graduated with a 2:2 in mech eng 12 years ago and have done software since so it’s reassuring to know I can give roughly accurate answers now.

[Marcus6275]

Just to clarify by ‘engine’ it was more to just give people an idea of something heavy and messy. Not actually suggesting someone would put a car engine on it, but smaller ones like from a lawn mower (https://engines.honda.com/models/application/lawnmower - 15kg)

The coating on the ex-Amazon flooring might be ideal, but it’d still be a good idea to have a sink to drain into as well. If the budget allows having two layers of 18mm certainly wouldn’t hurt.