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Scootered

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To preface: I have absolutely NO idea what I'm doing when it comes to machining. Nothing. I have never even seen a machine shop. I have no idea about terminology, technique, or proper practices.

What I do have is an interest in learning a little bit, and figuring out how to adequately describe what I hope to accomplish at the end of all of this. And since I'm a complete and total newbie, I ask for a tad bit of forbearance and gentleness. I was reading on another forum (apparently for professional machinists, and they utterly reamed a guy to pieces for asking a simple question, and sadistically enjoyed doing it. That's just wrong, meanspirited, and uncalled for. We all were at a place once where we knew nothing, so please remember what that was like and remember that I don't already know what I'm doing. Thanks!

Now on to the fun part!

I am looking to describe two metal parts that I'd eventually like to get made, for a project I've been working on for a long time. Before I go any further, the nature of the project isn't relevant, nor is the final purpose for the metal parts relevant. ;) The reason I state this up front is, I've found that every time I try to describe the end result I'm looking for, everyone always stops thinking outside the box, and tells me that they can't do it, it won't work, it isn't possible, or it doesn't exist. I have found that if I just describe a thing in terms of what it's generalities are, and only give specifics where needed, I always arrive at the exact result I'm looking for. Process isn't relevant. End results are. So, describing what it is, and what it's going to be used for will change the way everyone thinks, and will prevent finding an efficient and workable solution. I have a lifetime of experience watching this happen over and over, and can give real, specific examples if asked to.

If these two metal parts were to be made out of wood, plastic, or any other material other than metal, it would be a very simple matter to describe them in very simple terms, and an even more simple matter to produce them at home, in the sanctity of the garage. However, in my research on metalworking, I've discovered that there is a significantly-greater demand for near-inhuman levels of precision. A brief example: if someone were to say to me, "I need a 1/4" hole in this thing, right about there" I would go to my garage, get a 1/4" drill bit, and drill the hole. From what I've found in the machinist's world, the hole has to be described to 0.0001" of precision both in terms of center-position and diameter. (slight exaggeration of numbers, sorry!).

Let me state up front that this kind of precision simply is neither required, nor necessary. I'm not making rocket parts! In my world, and for the purposes of this project, 1/64" of an inch is close enough.

I have a need for two small pieces of flat steel bar. I know there are hundreds, if not thousands of different alloys of steel, so this is one complicating issue for me. I don't know enough about how to accurately and adequately describe all the alloys, what they do, their properties, or anything about them. What I would like is a cheap, regular, plain steel that anyone can pick up anywhere, can be welded to a section of steel pipe I already have, and wouldn't cost a great deal. It doesn't have to be high-quality, rare-alloy, super-duper steel, just regular, plain, run-of-the-mill steel. Sorry for my ignorance. That's why I am here.

These two pieces will end up being 3-1/2" long (remember that I'm not dealing with microscopic measurements here) and 1" wide. One of them will be 1/4" thick, with one flat side, and the other will be 3/8" thick, with a rounded "groove" on one side. On the reverse side of both pieces are lengthwise grooves. They both have a matching set of 1/2" holes in them. Again, microscopic measurements aren't required.

My concern is, I don't know, or understand metalworking/machining terminology well enough to even begin to describe or even draw these shapes in terms that a hobbyist or even a professional shop would understand, because NASA-level precision simply isn't required. I think in entirely different terms, and I'd like to learn enough to describe what I am looking for, in terms that are understandable in this world.

I have attached a very rough sketch of these shapes, which should make things much more simple, for the sake of discussion. There are no dimensions, or descriptions, just a drawing of the shapes. I hope this is an adequate starting point, for me to learn how to accurately describe them in terms understandable to a hobbyist.

289278

My ultimate goal is to find someone who would be willing to make them, without me having to mortgage my house or sell my car to pay for them. I'm not Bill Gates.

Could I please start a discussion on how to detail these sketches to make them into drawings that could be used to actually make these pieces?

Thanks!
 

jwmelvin

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I like your question. You need to decide what is important. This is an issue of tolerancing. I can post more later but you could do some reading on the issue.
 

4ssss

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I don't want to throw gas on your fire, but the last time I did a job like you want with someone that said " that's close enough" I ended up putting in over 35 hours on a job that should have been done in 4. It only ended after I had enough of his " close enough revisions", and told him to find someone else. Of course I didn't get paid if you're wondering. From that point on if there's no print or dimensioned sketch, there's not going to be any work done.
 
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Shootymacshootface

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Those could eisily be made on a mill with common tooling.
Are you trying to learn how ro make these parts yourself?
If you want a machinist to make them for you, you just supply a blueprint or a drawings with dementions on it and let the machinist do what he does.
 

jwmelvin

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Some things do matter to you; I’m guessing you care that the grooves mate. So for that you might dimension from one peak to the next and designate that as typical.

Also the holes seem likely to allow relative motion of some parts? Allowing for sufficient tolerance on diameter means the holes can be drilled instead of also reamed or bored. That makes a big difference. If the holes are, say +-0.010 then someone reading the drawing knows they may be drilled.

The radiused back running along one of the parts looks to be the most difficult feature. Knowing the tolerance on radius is important. You said it would be welded to a pipe. I would think that a c-channel or a rectilinear recess rather than the radius would be better because it facilitates line contact for welding. But you don’t want that. Are you okay with the radius being more than that of the pipe? The tolerance will be driven by the tolerance of the pipe and your design considerations.
 

ttabbal

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Welcome. We're easy going around here, no worries about being new.

Sounds like you want a mild steel. 1018 or similar should work unless you have have high heat or other stress in the application.

Your picture looks simple enough. I would add a drawing generated from the same CAD model with dimensions. Don't worry about the precision you don't need. Give nominal dimensions like 1.5" and a note on the sheet stating the tolerance. +/-0.005 is pretty common. 1/64 is about 0.015. If the part needs to fit inside something else, you might want +0/-0.005. You also need to specify the radius of the curved part and the angle of the slots. The slots look like a typical 90 degree V, but if you want someone to build it, you need to tell them what it is.

A pro shop probably won't want the bother to set up for two single unit parts. So they give a high price. A hobbyist might be willing to make them for a reasonable price. It won't be free though. Saw that with some people thinking 3D printed parts should be super cheap.

I'm curious about how people would cut that radius. A fly cutter held at 90 degrees might work... A very large ball nose end mill..

4ssss makes a good point. Machinists work to the drawings. We aren't generally artists and revisions cost. For a hobby job I would require payment up front and make it clear that if the part meets the stated tolerance, that transaction is complete. If you want changes, that's a whole new conversation.
 
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Robo_Pi

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Could I please start a discussion on how to detail these sketches to make them into drawings that could be used to actually make these pieces?
All you need to do is add dimensions and tolerances. If the drawings aren't clear the machinist will let you know what they are unclear on.

The drawings you've posted thus far have me totally wondering what size they are. Are they 1/4" long? 4" long? 4 feet long?

Without dimensions on the drawing I have no idea what size these parts might be or whether I could even make them. If they are 4" long (or in that ballpark) I might be able to deal with them. If they are 1/4" long I really don't have tiny precision machines to deal with parts that small. If they are 4 feet long, again, I don't have machines to handle work that large. So until I see dimensions I have no clue what your parts are even like.

Edited to add:

Ok, never mind, I see you did call out demensions in the text. So they are in the 4" ballpark. That's certainly an easy size to work with. Almost any hobbyist should be able to deal with a project that size. The next question is do the grooves need to mate?
 
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Bluedog

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I get why you didn’t want to post the final use or intention for the parts, but I think it could be a help. With the final goal in mind, someone might be able to think more outside the box. They might have a better idea of tolerances required, or might have suggestions on changes that could make he parts easier (cheaper) to make and accomplish the same goal. For instance, if the curved piece is just to fit the radius of the pipe and be welded on, farm fit might be good enough. The curve could be cut in steps with a small end mill and be good enough.
 

Robo_Pi

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For instance, if the curved piece is just to fit the radius of the pipe and be welded on, farm fit might be good enough. The curve could be cut in steps with a small end mill and be good enough.
I was thinking the same thing. In fact, if it's going to be welded onto the pipe a simple V-grove would be just fine. Setting up to cut a perfectly matched radius would be a total waste of time.

In fact, I would draw in a v-groove in place of the radius and just mark it V-groove clearance for 3/4" diameter pipe (or whatever size pipe it will be welded to). That way the machinist could know how steep the V-groove needs to be based on the pipe diameter for best fit.
 
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Shootymacshootface

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When making parts that will are designed to be welded to something else it is best to include clearance for a good weld.
 

Robo_Pi

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When making parts that will are designed to be welded to something else it is best to include clearance for a good weld.
That's an interesting point I wasn't even aware of myself. Where would you put this clearance? Would this be in the form of chamfering the edges of the piece where it meets the pipe? If so, how would you determine how much chamfer is needed? I wouldn't have thought of that. I would have just slapped it on there and welded it as is. :grin: That's why I'm not a professional welder I guess.
 

cathead

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Welcome to HM. I thoroughly enjoyed reading your dissertation to the end. One only needs to know enough to accomplish what
one needs to do the job. The rest can be found in Machinery's Handbook if needed. In general parts only need to be as accurate as
the application requires. The difficult part is that one needs a bit of tools to get started. Being a hands-on person helps too.
One very good way to get started would be to get to know a machinist or two or at least someone with a milling machine and
have them show you a few things. That's what I did years ago. I stopped by a machine shop with totally something else in
mind and ended up being tutored a bit and eventually buying several lathes and a mill and a lot of other accoutrements.
Anyway, it is a great hobby so if you delve into the abyss, I hope you enjoy it as much as I have.:encourage:
 

Shootymacshootface

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A 45* chamfer on the part only where the welding will be. The width of the chamfer will be dictated by the thickness of the pipe. The weld can only be as strong as the weakest part.
 

Robo_Pi

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A 45* chamfer on the part only where the welding will be. The width of the chamfer will be dictated by the thickness of the pipe. The weld can only be as strong as the weakest part.
Well, I'm certainly learning something in this thread. :grin:

Thanks.

So even the pipe wall thickness needs to be called out on the drawning. Either that, or the correct dimensions of the chamfer. It's more complicated than even I thought. Of course it all depends on the application too. If there's not going to be any stress on this part you could probably get by just welding it on without a chamfer. But if you're building something important that needs to stand up to maximum stress using the correct welding geometry is definitely the best way to go. This is why it's also important to know how the part will be used. If all the pressure will just be toward the pipe then all the weld needs to do is hold the part in place when it's not being used. When it's actually being used the weld isn't really doing much of anything. In that case it could just be tack welded on. So the application of use can make a world of difference in what's critical and what isn't.
 

brino

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I was reading on another forum (apparently for professional machinists, and they utterly reamed a guy to pieces for asking a simple question, and sadistically enjoyed doing it.
That will NOT happen here!
-brino
 

Bob Korves

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Ulma Doctor

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i love it when someone tells me it can't be done :grin:
it really just adds fuel to the fire, for me.
to find another way of doing the exact same thing, and showing the end result, is better than most anything i could dream of.

i sense the force is strong in the newbie, welcome down the rabbit hole my friend.
there was times when everyone you encounter here was in a similar situation, not knowing anything about machining.

fear not, your knowledge grows in 2 ways.
first, you learn by watching/reading/listening/asking questions
second, by doing

if you were so inclined, you could reproduce the parts you wish to make with simple hand tools
a hacksaw, a triangular file, a round file, a bastard file, and a drill, is all you would need other than a work holding device.

if you wanted an excuse to buy a metal shaper, this would be the ultimate excuse. :grin:
the longitudinal grooves could easily be produced.
the forming of the concave relief could also be a rewarding experience too!

Use of a vertical or horizontal milling machine would be another way of doing the same things.

your desire will be the deciding factor
there is a will, and a couple ways :cool:
 

Robo_Pi

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if you wanted an excuse to buy a metal shaper, this would be the ultimate excuse.
Living alone as a hermit I don't need to have excuses anymore. Even my cats have passed on, and I don't think my goldfish would even know that I bought one.

I'm actually looking at this one right now:



Not having an excuse is not what's stopping me from getting it though.

Not having the cash to pay for it is my current problem. :grin:

And it was just marked down from $999 to $799.

Still a bit over my budget. I need to find one for something like $300. :grin:
 

Scootered

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I like your question. You need to decide what is important. This is an issue of tolerancing. I can post more later but you could do some reading on the issue.
Reading what?

If you'll forgive the flippant, intended-to-be-humourous response: I didn't know I could find that information in Readers' Digest! Wow!

A title of a text, or a link to a webpage might help, since clearly you know more about it than I do.

Thanks!
 

Scootered

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I don't want to throw gas on your fire, but the last time I did a job like you want with someone that said " that's close enough" I ended up putting in over 35 hours on a job that should have been done in 4. It only ended after I had enough of his " close enough revisions", and told him to find someone else. Of course I didn't get paid if you're wondering. From that point on if there's no print or dimensioned sketch, there's not going to be any work done.
Thanks for taking the time to reply. I have never asked anyone to make this, so telling me what you wouldn't do doesn't really help me figure out what I need to do. Thanks!
 

Scootered

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Those could eisily be made on a mill with common tooling.
Are you trying to learn how ro make these parts yourself?
If you want a machinist to make them for you, you just supply a blueprint or a drawings with dementions on it and let the machinist do what he does.
Thanks for the reply. Did you see the part where I wanted to start a discussion on learning what I needed to know, about how to dimension, detail, and mark up the drawings?
 

benmychree

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Shapers are a drug on the market, especially large ones. Small ones bring good money, but that one is not small. Never buy a shaper that does not have it's vise. Even if sold for half the lowered price it would not be a deal without the vise.
 

cbellanca

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Remember there are no dumb questions. Only dumb answers. I see this site as a learning experience for me even though I have been around machining operations for over 50 years. So keep asking those questions. I do.
Regards, Chuck
 

Robo_Pi

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Shapers are a drug on the market, especially large ones. Small ones bring good money, but that one is not small. Never buy a shaper that does not have it's vise. Even if sold for half the lowered price it would not be a deal without the vise.
Just between you and me, if they offered me the one in the picture for $300 I'd be on my way to pick it up , vice or no vice.

But yeah, I'm not paying $799 for it. :grin:
 

Robo_Pi

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Thanks for the reply. Did you see the part where I wanted to start a discussion on learning what I needed to know, about how to dimension, detail, and mark up the drawings?
What CAD program are you using?
 

MarkM

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I like how you believe in yourself. The mind is the strongest muscle we have . It s all sttitude!
Take your part and look at it in three views. Top view, Front view, and side view. In those views you dimension what you want. Circles dotted circles, lines and dotted lines represent seen and unseen or features. Like a hole and a thread. What you see in your views is drawn. A hole one inch from an edge will have a circle drawn and the dimension away from the edge given and size of hole. It doesn t have to be an engineers drawing.Some times top and side views are enough. A tolerance is given for the operation. The more decimals used the more precision. Machinist love seeing two decimals.
X left and right y forward and back, z up and down is how we machine.
Just some things to ponder. Go look at an engineers drawing for a simple shaft. Look into tolerances study for a bit and send me a drawing of your part or whatever and l ill help to educate yourself and could make that if you need. Simple flatbar will do.
Something to think about being a maker and working with machinist. Try to understand tooling and processes. Like your part. Do you require a v groove, a radius, or would a simple small slot be sufficent from a tiny endmill.
 
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Scootered

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Some things do matter to you; I’m guessing you care that the grooves mate. So for that you might dimension from one peak to the next and designate that as typical.

Also the holes seem likely to allow relative motion of some parts? Allowing for sufficient tolerance on diameter means the holes can be drilled instead of also reamed or bored. That makes a big difference. If the holes are, say +-0.010 then someone reading the drawing knows they may be drilled.

The radiused back running along one of the parts looks to be the most difficult feature. Knowing the tolerance on radius is important. You said it would be welded to a pipe. I would think that a c-channel or a rectilinear recess rather than the radius would be better because it facilitates line contact for welding. But you don’t want that. Are you okay with the radius being more than that of the pipe? The tolerance will be driven by the tolerance of the pipe and your design considerations.
You're right. Some things do matter. The grooves mating, or knowing what the dimensions are isn't one of them. They are specifically intended not to mate, as they are intended to grasp something between them. Ooops, I gave something away!

The only way I can think of to describe it, is to just show a sketch of the cross section. It's attached. The red part is where I thought the weld would go. If the pipe just fits up inside the "groove" then the weld will have a better area to hold. If there's all sorts of space between the pipe and the part, well, I could foresee problems.

The thickness of the walls of the pipe is (at a guess, I've never measured it) a little more than 1/8" and it's 1-1/2" in diameter. So that would be the radius, I'm guessing.

Does this help any?
 

Scootered

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I like how you believe in yourself. The mind is the strongest muscle we have . It s all sttitude!
Take your part and look at it in three views. Top view, Front view, and side view. In those views you dimension what you want. Circles dotted circles, lines and dotted lines represent seen and unseen or features. Like a hole and a thread. What you see in your views is drawn. A hole one inch from an edge will have a circle drawn and the dimension away from the edge given and size of hole. It doesn t have to be an engineers drawing.Some times top and side views are enough. A tolerance is given for the operation. The more decimals used the more precision. Machinist love seeing two decimals.
X left and right y forward and back, z up and down is how we machine.
Just some things to ponder. Go look at an engineers drawing for a simple shaft. Look into tolerances study for a bit and send me a drawing of your part or whatever and l ill help to educate yourself and could make that if you need. Simple flatbar will do.
Something to think about being a maker and working with machinist. Try to understand tooling and processes. Like your part. Do you require a v groove, a radius, or would a simple small slot be sufficent from a tiny endmill.
Those are just a few of the very many things I have never considered. One thing sticks out. If I don't know what "tooling" and "processes" are, I really can't understand them. As I mentioned, if this were wood, I could figure it out. I'd take a router with a triangular profile, and cut my grooves. I'd take one with a much bigger round profile, and cut out the bottom groove. And I have a nice 1/2" forstner bit that would cut my holes. But this isn't wood, and I don't have a clue how metal machines work. I think I have a great deal to learn.
 
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