| On Thu, 18 Jan 2007 21:54:50 -0600, "Morris Dovey"
|| Morris Dovey wrote:
||| <toast mode=oxy-acetylene>
|| Possibly I was a tad harsh. On a web page at the link in my sig I
|| posted photos of every step (except soldering up cables) in the
|| construction of a 3-1/2 axis machine with a 1/4800" step size; and
|| posted a drawing of the chassis to
|| news:alt.binaries.pictures.woodworking before starting
|| construction. The photo of the final step is still on the web
|| page, along with a photo taken during the testing stage and
|| another of the stepper controller guts.
|| I put in more than 100 hours researching the parts and will
|| estimate at least another 500 hours in actual development
|| activity. The cost of (all new) parts ran a little over $1400.
|| None of the parts were hard to find. Identifying the most suitable
|| parts and finding reliable sources at reasonable prices /was/
| The machine I think he was referring to doing something similar to
| was not really a true 3 axis machine, but more like a printer. So
| sort of 2 axis, one of which only having a few inches of travel,
| plus the feed mechanism to move the wood through. Whether that
| actually reduces the complexity of the machine or not I don't know,
| but if Sears can sell it for $1900 then I'm guessing there isn't
| $1400 of parts in it.
From the published specs, I'm fairly sure you're right.
|| While you may be able to do a better job in less time, I'll guess
|| that you'll need to spend at least as much time as I did to do a
|| comparable job. If so, you can feel secure in knowing that your
|| time is worth $500/600hr or approximately $0.83/hr as a machine
|| designer. Alternatively, you can allocate the whole $500 to
|| hardware and feel insecure knowing that your time is worth butkus
|| and that your "kit" has only toy value.
| Remember you are spreading that cost over all the units you sell, so
| if you could sell 100 machines development only accounts for 6 hours
| per machine. And if you were going to build one for your own use,
| well you had to invest all that time anyway so it doesn't really
| count. What really matters is how long it takes to build one now
| that you know what you're doing and have the prototype to refer to.
Absolutely true in every way - although the "if" should probably be
set in uppercase bold italic. Throughout the project, I worked up a
bill of materials and a vendor list so that I could offer the little
monster as a product with (standard) parts. I did receive a number of
e-mails expressing interest in purchasing copies at various
(below-parts-cost) prices. I guess it must have left me with a raw
spot for people who aren't willing to give/receive value-for-value.
Even having built one and having the part programs, a bill of
materials, a vendor list, and a routing list on hand doesn't reduce
either the parts cost or the labor content to anywhere near the level
that people were willing to fork out for. FWIW, as soon as a machine
moves from the "something I'm building for myself" into the "product
for sale" classification, the rules change rather noticably.
I'd label your last sentence as "conditionally true" - because it's
only so if the customer wants no further products or parts, /ever/.
Product development/improvement activities /do/ have associated cost,
and you're disallowing the use of sales revenue to fund those
activities. I'm inclined to view that as (at best) "unwise".
| I've been thinking about trying to sell drum sander kits, but I
| wouldn't consider the time I put into building my first one as part
| of the cost. I was going to do that anyway, and the sander is
| paying for itself.
Yup - I'm aware of your efforts and I think you did well. I'm just
holding out for someone to offer a 45-pound complete,
lifetime-guaranteed, dustless, self-feeding version with
keyboard/digital thickness adjustment and drum/feed speed controls,
and incorporating a paper clog prevention feature - all for $250 <eg>
DeSoto, Iowa USA