Laser Cutter: Choice of 3 cutters and 2 funding models

Tom Gardner

We need a new laser cutter for the reasons defined in Nic Marshall's proposal Hackspace Proposal. While the principal is not strongly contested, there has been dissatisfaction with some of the details, which has resulted in considerable discussion about that particular funding model. The principal points of contention vary, but centre around are how much money should come from the HackSpace kitty, how fast it should be repaid (if ever), and whether a surplus should be built up to buy the next cutter. It has been suggested that a “duel” should be held, and David Henshall produced a considerably different funding model in Hackspace Proposal. This proposal is another entry in the “duel”.

This proposal retains many features in Nic's proposal, and defines capital outlay and usage prices for 6 different options:

  • A0, A1 and A2 cutters, since it may be desirable and/or necessary to opt for a smaller cutter
  • two sums from the HackSpace kitty, one which is repaid from usage prices and one that is a simple gift

Hopefully this range of choices will remove many objections, and enable a swift progression to purchasing a cutter.

Assumptions carried over from Nic's proposal:

  • capital outlay for a fully installed and operational cutter of £6900 (A0) or £5900 (A1) or £4900 (A2)
  • usage 10 hrs/week, 50 weeks/year ⇒ 500 hrs/year
  • cutter lifetime 5 years
  • tube and mirror lifetime and replacement costs
  • members can choose to make gifts to enable a purchase
  • the cutter will be owned and maintained by HackSpace

This proposal presumes that:

  • we do not want to have to repeat this process at the end of the cutter's life
  • it is unacceptable to prevent HackSpace members making other large purchases for a long period of time
  • the committee should not have to be continually concerned about HackSpace's finances

Suggested process: determine how much members will contribute, weed out impossible or undesirable options, and then put remaining options to the vote.

The principal features and benefits are:

  1. a range of tiered usage prices varying from £1 to £4 per hour (for some options £8/hr or £9/hr in the first year only). Benefit: much lower than current costs
  2. a range of member gifts varying from £2400 to £6000. Benefit: once we know how much people will donate, we can ignore impossible options and concentrate on what's feasible.
  3. self-sustaining. Benefit: no need to get yet another round of members gifts nor repeat this whole wretched process all over again in 5 years time!
  4. self-financing after the initial purchase. Benefit: HackSpace can continue to grow in other ways, avoids penalising members not interested in the cutter, less worry for the committee
  5. non-profit. Benefit: minimal usage costs
  6. HackSpace contribution of either
    • small purchase £900, not repayable since it doesn't limit other member's interests and ambitions, and doesn't worry the committee, or
    • large purchase £2500, repayable so that other member's interests and ambitions can continue (albeit after a delay), and the committee doesn't have to worry (for too long)
  7. reduced risk to HackSpace finances. Benefit: committee doesn't have to worry so much
  8. reassessment of usage prices yearly and whenever milestones 1 and 2 are passed
  9. more choices. Benefit: choose between higher/lower member gifts, and lower/higher hourly usage costs, and larger/smaller cutters
  10. more likely to succeed. See how much can be raised, and then “cut our cloth according to our means”. Benefit: not an all-or-nothing choice, members and the committee aren't forced into a corner, and can choose which best suits their own requirements

Capex for this cutter is outlined below. Capex for the next cutter comes from this cutter's usage price. Predictable opex (tube, mirrors) comes from this cutter's usage price.

Three tiers to hourly usage prices:

  1. primary tier payable only until Milestone1. If and only if the cutter is funded as a “large purchase” then Milestone1 occurs whenever the loan has been repaid (budgeted for 1 year). If it is a “small purchase” then it Milestone1 occurs immediately; in effect this tier is not payable.
  2. secondary tier payable until Milestone2. Milestone2 occurs whenever there is a sufficient surplus to purchase the next cutter without all this tedious argument. Budgeted for 5 years, but could occur sooner if cutter prices reduce over time or usage is higher than budgeted.
  3. tertiary tier payable thereafter

It can be seen that the principal tradeoffs are between how much members are prepared to offer as gifts, and the first year's usage price.

option name A0-2500 A1-2500 A2-2500
capexCapital cost £6,900 £5,900 £4,900
HackSpace loan, repayable £2,500 £2,500 £2,500
Members' gifts £4,400 £3,400 £2,400
opexYear 1 primary tier usage price per hour £9 £9 £8
Year 2 secondary tier usage price per hour £4 £4 £3
Year 3 secondary tier usage price per hour £4 £4 £3
Year 4 secondary tier usage price per hour £4 £4 £3
Year 5 secondary tier usage price per hour £4 £4 £3
Year 6+ tertiary tier usage price per hour £1 £1 £1
option name A0-900 A1-900 A2-900
capexCapital cost £6,900 £5,900 £4,900
HackSpace loan, non-repayable £900 £900 £900
Members' gifts £6,000 £5,000 £4,000
opexYear 1 secondary tier usage price per hour £4 £4 £3
Year 2 secondary tier usage price per hour £4 £4 £3
Year 3 secondary tier usage price per hour £4 £4 £3
Year 4 secondary tier usage price per hour £4 £4 £3
Year 5 secondary tier usage price per hour £4 £4 £3
Year 6+ tertiary tier usage price per hour £1 £1 £1


  1. Nic's assumptions are simply taken for granted, without being checked
  2. all tier prices rounded up for simplicity
  3. if usage more than 500 hours/year, then primary tier payable for a shorter time, and vice versa
  4. if usage more than 500 hours/year, then secondary tier payable for a shorter time, and vice versa
  5. most spreadsheets have errors :( I offer one mars bar for every significant error.
  6. this neither requires nor precludes David H's idea of giving each member 30 mins/year free usage, since that would come out of the normal HackSpace operating budget, not a special laser cutter budget. Personally I like that idea and would want to see it implemented whatever is or isn't purchased
  • botlab/hsproposals/hsproposals_2015-06-17-lasercutter_3_cutters_2_funding_models
  • Last modified: 3 years ago
  • by felix.h