how do you start a project

[artrans]

I was thinking over the weekend and going over some plans and want to build a couple of things. And in looking over differant plans at times it seems over whelming and was wonding the way some of you go about starting a project. So one lets assume we have the matrial
on hand.do you make one piece at a time. Or do you rough out many pieces. do you start
with the harder pieces first. I am used to build r/c planes and those plans have steps 1-what ever and at the end your finished. very interested in how some of you guys go about starting
a project thank you

 

[mklotz]

Art,

You start by thinking through the entire fabrication process. If there's any complexity to the item you're making, you should put together a (written) fab process sheet. It will describe not only the order in which the parts are made, but also the tools used to perform each operation on the part and the order in which those operations are performed. If you have a "steel trap" type mind, you can do all this in your head but, until you've got a few projects under your belt, I strongly advise writing it all out.

In a production environment everything is made to tolerances established such that the finished parts will assemble correctly into the final product. In the home shop, it's more typical to make parts to fit their mating part. An oft-mentioned example of this is boring the cylinder to (nominal) size and then making the piston to fit the resulting bore, whatever size it turns out to be. Thus you need to make the cylinder before you make the piston.

Another thing to consider, particularly if working with castings, is the need to establish reference surfaces from which to measure and to guide the making of parts that relate to the part being machined.

You also need to think about how you will hold certain parts. Careful consideration of the manufacturing sequence will help you avoid clamping on already machined threads or being forced to make fixtures to machine that last detail.

There is no cut-and-dried, one-size-fits-all answer to your question. Each job has its own peculiarities and needs to be fully thought through before making the first cut. Planning exactly how you will proceed is arguably the most difficult task in making something but it's certainly the most useful thing you can do, especially so if you're new to the machining venue. If you watch experienced machinists, you may not think they're doing this but that's only because they've internalized the sequence by dint of their experience.

 

[shred]

Marv's advice is spot-on as usual.

With all else equal, I like the 'make the hardest part first' method for little engines that Rake60 posted long ago. You're most fired up about the project, don't have a lot of get-it-done-now-ness that comes along at the end, and once you get that part under your belt, it's all downhill.. in theory

I also try to plan for parts and tools on-hand since I mostly mail-order them, though sometimes I don't-- In fact I'm anxiously awaiting some funny (to me) metric taps to finish the Loco project. Should have ordered them months ago, but I thought I had them covered.

 

[tel]

Personally, I like to start from the ground up - ie base, frames etc etc. This gives us something to hang the various bits on as they are made. Usually, the last part I make is the flywheel.

 

[kf2qd]

Generally by making mistakes...

 

[rake60]

When I start a new project, I look for the part that appears to be the most
complex and difficult to make. That will be the first part machined.
If a cam or unusual cylinder would happen to be beyond my personal skill,
a batch of easily made columns, frames and shafts are pretty much useless.

Rick

 

[SignalFailure]

If you do what Marv suggests and also include some dimensions etc you might avoid a nasty surprise later on. I recently started a project in the same way as Tel... made the base, standards, bearings, cylinder supports, cylinder block; then found out that the cylinder block (made as per the plans) was too small to accomodate the holes for the supports. Grrrrrr! It's a sad fact that lots of plans, even those you might pay good money for, have errors.

 

[stevehuckss396]

When I start a new project, I look for the part that appears to be the most
complex and difficult to make. That will be the first part machined.
If a cam or unusual cylinder would happen to be beyond my personal skill,
a batch of easily made columns, frames and shafts are pretty much useless.

Rick

I'm with Rick. Even if there is a part that requires alot of work, doese'nt have to be that hard, I usually try to get them out of the way first.

 

[Mainer]

For a part, think through the required sequence of operations, so you don't end up with the part halfway machined and no way to hold onto it.

Also, I find it useful to re-draw the part using a CAD program. That helps me visualize the part better, and it gives me a chance to add helpful dimensions that may not be on the original drawing.

 

[Kludge]

Pretty much what's been said is good advice. The only thing I'd add is that using a build order that allows one to correct minor problems as they crop up was quite helpful to me when I was building before. (The name "Kludge" was well earned. ;D)

What Paul said about plans is true. If the numbers and/or proportions don't seem to add up right, double or triple check because they probably don't. Marv's running (or maybe walking very quickly ) advice about keeping a calculator at hand in the shop is excellent, and this is one reason why. Plans lie.

Simple, isn't it.

Best regards,

Kludge

 

[joeby]

Starting a project isn't the hard part for me, I don't seem to know how to finish one!

Kevin

 

[lathe nut]

my first thing is to see if I have enough stuff to do the project with that said, I get my metal at a scrap place, then they are not the right size to whittling I go, got a few small things done and will post a pic of one of them, but what really helps me is to these fellows and Paula post the pictures of how they hold the parts to cut them, that is where I am in need of help, so let's watch the masters and do what they do, what a well spring of wisdom we have here, Lath Nut

 

[Brian Rupnow]

Very interesting topic, and a lot of good answers so far. Of course, everybody does it a little differently. I do it this way. First of all, something has to get me started thinking about a new project. Many times, the new project will arise from a need which is recognized from a previous project. --A good example, ---I was always fascinated by steam engines, but only in the last year have I actually started building them. The first two I built were other peoples designs, without any real modification, just to get some experience using a lathe and a mill. The third was based on someone eldes design, but modified--(the beam engine.) The fourth was my twin cylinder horizontal, which was my own design. The need to control the speed at which it ran lead me into the flyball governor project---and that lead me into the Varying load machine which I am currently building. Firstly, I research as much as I can to see what other people have done. This is generally now done by direct internet search---I used to go to the library to research new projects. Then I have to consider if I am technically capable of the new project. I can do a lot of things, but there are many things that I either don't know how to do, don't have the machinery to do, or can't afford to do!!! And then I make a rough sketch--If you read my posts, you have probably seen some of them. Then I set down at my CAD station, and make a working design. Then I create detail drawings. As many others have said, I find the most challenging part, and make it first. This serves two functions---#1-It keeps me from making a bunch of simple parts, then having to abandon the project because there is some aspect of it that I am unable to make. And, #2--Once the hardest part is out of the way, the other parts seem to go more quickly. I only work on one part at a time, and I complete it before moving on to the next part. I generally assemble the parts as I make thm, rather than making all the parts first, then beginning assembly. If it is a complex machine, made up of a number of sub-assemblies, then I try to complete all of the sub assemblies, one at a time untill they are finished. I test run each sub assembly as its own small "mini project", then set it aside untill I have parts made that assemble with it.

 

[Marinesteam]

When I start a project, not that I have had that many, I give the prints a once over and then go through again part by part working out anything that doesn't make sense. Making notes and sketches to fill in missing or unclear information as I go along is helpful. Especially make sure that mating parts look correct (hole sizes, fits, etc..) together. Then I start picking material from the shelf and make a list of what is needed to purchase. Same goes for tooling.

Remember the 5 P's

Prior
Planning
Prevents
Poor
Performance

I start making chips using the material and tools that I have on hand while waiting for the items than need to be ordered.

With the compound steam engine that I am starting, I plan on machining the parts to be made from bar stock before tackling the castings. There is less room for error as it's much more difficult to replace a spoiled casting than a piece of bar stock. And I also need to gain some more confidence as well.

In the end, do it in the order that you are comfortable with.

Ken

 

[joeby]

I thought I'd throw a few comments out here; but keep in mind that when you have been making a living at machining parts it puts things in a different perspective, you don't have a choice as to what part you want to make or what to make first, for example.

One rule of thumb that I use is that it's easier to make a pin fit a hole than a hole to fit a pin. That will place the cylinder before the piston, the main and rod bearings before the crank, the head before the valves, etc. You can adjust for oversize bearings when you turn the crank journals, leave the piston oversize, or polish a thousandth or two off if it's too tight, that sort of thing. When you are finishing a hole, you are looking at a one-shot deal most times (ever use a .250" reamer and the hole ends up .252"?).

I don't start a project with the idea that there are parts I can't make. Too many people out there turn out VERY nice work with minimal tools. If you have the project started, then you have the incentive to work through the difficult parts. Running into an issue with machine or tooling will happen sooner or later. Flywheels too big for your lathe? I think I would look to borrow machine time in someones shop, or have someone else turn them for me. I don't really like doing that; but if it means shelving a project, then I would certainly consider it. I don't see asking for help as a bad thing.

Also, the starting with the "foundation" is a good idea. Much of your fitting and adjusting is going to start here, so why not eliminate having to remake a piston because you had to oversize the cylinder to clean up a bad casting, or remake the connecting rod because you got the main bearings off location?

Sketching out the assemblies and making notes has also become an early step in the building process for me. Mistakes happen, and I've found more than a few in purchased plans, and unfortunately, my own plans.

Kevin

 

[DICKEYBIRD]

One rule of thumb that I use is that it's easier to make a pin fit a hole than a hole to fit a pin.

So true Kevin; that one should be printed out & hanging up in everyones' shop! For me anyway, it's so much easier sneaking up on a critical dimension in the lathe than in the mill. If at all possible, I'd rather bore in the lathe than in the mill too.

Before learning that lesson, my sequence was usually a 5 step process:
(1) Make round part.
(2) Bore hole to fit.
(3) Check fit of parts.
(4) Scream bloody murder and throw round part in scrap drawer.
(5) Make round part #2 and vow never to make the same mistake again. ;D

 

[lane]

Think the whole process through. then start with the base and build up and out . fitting each part as it is made.

 

[Cedge]

A Cedge build begins long before the first metal is ever bought or scrounged. Lots of sketches (Crap-o-Cad V. 1.89 for Dummies) and then it all gets modeled in 3d to make sure the sketches didn't lie. Once the project is pretty solidly between my ears, I begin with the base and move to the cylinder(s) to establish a centerline elevation for the crank and support bearing locations.... etc.

Once those points of reference are identified, the rest comes along pretty smoothly, as long as I watch the cutting order of things and make sure there are always provisions made for the vise or chucks to hold the parts. I still get boxed in from time to time, but don't we all?

Steve

 

[Kludge]

Before learning that lesson, my sequence was usually a 5 step process:
(1) Make round part.
(2) Bore hole to fit.
(3) Check fit of parts.
(4) Scream bloody murder and throw round part in scrap drawer.
(5) Make round part #2 and vow never to make the same mistake again. ;D

And how many times did 5 loop back to 3 again? ;D

BEst regards,

Kludge

 

[Kludge]

One other thing that comes to mind is to consider where you may have to make a jig to make a part. What brought this to mind was one of Brian's builds, the 2 cylinder self starting engine that was completed in what was probably record time. He made a jig to help in building the crankshaft (or was it two jigs?) to keep everything nicely arranged and aligned and spaced and stuff. If that's the case and one can see it ahead of time, I'd be very tempted to make them first so once the build is started there don't have to be any interruptions along the line.

You may wind up making jigs that have multiple applications (even though you might not know it at the time) so making them hardy enough to last may be a cool thing to do.

Just my trade bead's worth ...

Best regards,

Kludge