Optimum number of Parts to make

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: cbrew, Harold_V

Post Reply
User avatar
SteveR
Posts: 372
Joined: Thu Jun 01, 2006 4:17 pm
Location: Los Angeles

Optimum number of Parts to make

Post by SteveR »

Since setups can be as time consuming as actually doing the machining to make a part, I've started making 4 of things where I need one at the moment, but might use more someday - like a pump or a bell or a coupler. This tries to balance the extra material cost with the setup time, particularly if the device has subparts where 2 are needed so that to make 1 gizmo, I need 2 subparts. In that case, I have to make 8 of the subpart, which is still manageable.

Is there a general rule about this that people follow? If you have to make 1 of something, do you automatically make 2? Or 3? or 10? Should we have a poll? Is there a better way to ask this?

Thanks,
SteveR
12x36 Enco Lathe, 9x42 Bridgeport, SMAW, O/A, Miller MIG w/gas, plasma
Not enough measuring tools...
1.5" Allen Models Consolidation on air.
1" FEF in progress
1" & 3/4" LE Projects
Measure twice, cut once, wait - it was supposed to be brass! :)
User avatar
cbrew
Posts: 3161
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Optimum number of Parts to make

Post by cbrew »

depends on the complexity of the setup and part. i also have mad extra if i have material.
If it is not live steam. its not worth it.
User avatar
NP317
Posts: 4557
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon, USA

Re: Optimum number of Parts to make

Post by NP317 »

I have made extra parts to add to the tool kit for steaming adventures. I never know what I might need when visiting tracks with my locos.
Having 'critical' spares is my "rule."
RussN
User avatar
Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Optimum number of Parts to make

Post by Bill Shields »

I started making a BvB steam pump for my current project & had to purchase materials.

Since minimum material orders (shipping cost as much as the material) -> gave me enough to make 5 pumps...so guess what?

Sold 3 or the 4 extras right away. Anybody need one?

Many production companies used to run a year's worth of orders for customers who would order JIT...until the government started taxing on the shelf unsold inventory.

When I am making things like steam fittings or valves..obit by the boxful until I run out of materials.
Too many things going on to bother listing them.
User avatar
gwrdriver
Posts: 3439
Joined: Mon Jan 06, 2003 10:31 am
Location: Nashville Tennessee

Re: Optimum number of Parts to make

Post by gwrdriver »

"Parts" is another thing, but over the years I've tended to over-estimate what materials I will probably use more of in the future and have ended up with quite a bit of surplus. "Quite a bit" is of course relative, and some of that was the result of buying "opportunities" that were too good to pass up, but in general I now tend not to buy any more material than I need to make the parts, and may a little extra, just in case.
GWRdriver
Nashville TN
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: Optimum number of Parts to make

Post by Dick_Morris »

If there is no significant additional investment (i.e., purchased castings), I often machine one or two extra. Not so much to have extras, but so I can use one to test set ups and so I will still have what I need after I lose one to the inevitable machining error, failure of the set up, etc. I typically don't assemble the extra parts, but will save them in case they are needed at some future date.

As for extra material, I finally bit the bullet and spent $2-300 to buy a stock of model sized rods, bars, nuts and bolts that I might need. It saves a lot of frustration when I can just go to the shelf and pull the material I need rather than place an order, hope they have it in stock, and then wait several days for delivery.

That brings to mind the days when an order to Cole's required several days for the order to reach them in the mail and then another week or more for it to be returned by mail. Even in Alaska I not uncommon to get items within two or three days of my order, rather than waiting three weeks from when the order is sent.
FLtenwheeler
Posts: 1595
Joined: Sun Jan 05, 2003 8:47 am
Location: Florida, on the Lake Wales Ridge

Re: Optimum number of Parts to make

Post by FLtenwheeler »

A tool and die maker one knew always made 3 of everything. It did not matter what it was. Complete engines or locomotives.

Tim
He who dies with the most unfinished projects: Should of put more time into their hobby.
RONALD
Posts: 754
Joined: Sun Oct 26, 2003 7:27 am

Re: Optimum number of Parts to make

Post by RONALD »

Ah, yes, the optimum number of parts!

Attached are several photo of my Lost Foam work; always make enough foam patterns to cover errors in metal pouring.

Also, there is a Lost Wax cast tree of Switch Rail Braces; try to get as many as you can in each flask.

Last photo is of assorted castings in iron, bronze, or aluminum.
DSCN1411.JPG
DSCN1423.JPG
DSC_1910.JPG
DSCN2634.JPG
Library - 2897.jpg
User avatar
Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Optimum number of Parts to make

Post by Bill Shields »

How many extra anvils do you have floating around?
Too many things going on to bother listing them.
RONALD
Posts: 754
Joined: Sun Oct 26, 2003 7:27 am

Re: Optimum number of Parts to make

Post by RONALD »

Bill, Not being a Anvil Aficionado, can't tell you much about anvils.

This one tho, was headed to the Dumpster when I saved it, as was the other one of similar size that I have in my foundry.

Could be from 1908, when the school started, but was just junk to those who were cleaning out a closed machine-shop classroom.

Today, at the school, no more real shops, just STEM with very small tools; I doubt that there are any anvils of that size.
User avatar
Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Optimum number of Parts to make

Post by Bill Shields »

My only anvil is made from NYCRR 120# rail.

Like you -> I inherited it..
Too many things going on to bother listing them.
James Powell
Posts: 504
Joined: Fri Oct 28, 2011 10:42 pm

Re: Optimum number of Parts to make

Post by James Powell »

When Harry Boneham made his 9 cylinder radial, he started out making 11 cylinders.

It turns out that Wright Whirlwind cylinders look remarkably like 1920's/30's Harley cylinders...

(Photos on the Toronto Society of Model Engineers website- no good way to link to them, but if you search Harry Boneham, they come up...)

James
Post Reply