Machine work, pricing, emachineshop.com

[masraum]

All, I've got a pinion from a G50/50 that I'm going to use as a conversation piece on my desk.

I have 2 questions.

1 Does anyone know what the threads on the end of the pinion are? It's from a G50/50. I think it maybe a 993 tranny. It seems to be 30mm I think it may be a 1.25 thread pitch. I counted about 7 threads per 10mm, but I think the way I counted may have been off and maybe it was supposed to be 8threads/10mm which would give me 1.25.

2 I'd like to have a base created that I could screw the threaded end into that would stand it up. I was thinking about 8" or 20cm in diameter for stability and proportion and either 20 or 25mm thick and round (the threads are about 18mm so 20 mm would probably be the min thickness). The plan was to make it Al or steel. I went to emachineshop.com and created the drawing and picked their cheapest Al and a CNC mill as the machine, and even with the most basic design the part was $235 shipped. With a slightly more complex design for looks the price was almost $300. Yowza. Is this price way out of range or am I just going to have to scrap this project until I can make the thing myself.

the pinion (much bigger than I expected)


My more elaborate, decorative design for a base



When I saw how expensive the above design was I removed the 6 holes and the recessed portion on the bottom. So for a round disk with one threaded hole in the center and one beveled edge, the cost was ~$235. The pinion is at least 10 lbs and is about 15" long, so I think I need a base that's at least 6" across, and 8 would probably be better.

So, does anyone here think that either emachineshops price is way out of line or know of a way to have something like this made much much cheaper? (I'm not looking for handouts this time)

Thanks for any ideas that you may have.

[widebody911]

I've heard that they're quite expensive.

[masraum]

Hmm, I wonder if I could take my drawing from their software (that's really easy to use, BTW) and have a part made at a regular machine shop. The software normally saves in ems format, but you can export to dxf format which is says is an autocad format. I have autocad, but never bothered to learn how to use it.

[jim72911t]

I manage a machine shop and quoting is one of my many responsibilities, so I'll chime in.

$235 seems a bit high, but not by much, actually. The problem you are going to run into is that you only need one part, and as I tell my customers all the time, the cost is in the setup. If I were going to make that piece on one of the CNC machines, I'd charge a minimum of $150 for setup/programming, and to that I'd add material costs ($20 max), finishing (not much), and shipping. That gets you pretty close to $200 right there. One thing to think about is that I like each of my machines to make about $100/hr, and they aren't making money when they aren't making parts, hence the high setup costs.

Your on the right track: take your drawing, both paper and electronic, to local machine shops and have them give you a quote. Chances are you can find a hungry shop to make that on a manual machine for $50-$100 (just guessing), as I see no reason that it needs to be CNC'd, especially for just one piece.

(I'd offer to quote it myself, but we are more of a production shop and generally don't do one-offs. If you need 100 or so, drop me a line )

Good luck. You should be able to find someone locally to knock that out in an afternoon.

Jim

[masraum]

What would likely be the cheapest way to have a basic beveled edge disk created? Lathe?

What sort of equipment would be required to drill a hole 30mm dia? I've got a small drill press. I'm guessing that a hole that big might tax a small press. And then there's the matter of the tapping of the hole. It seems that for most of the taps that I can find that are 30mm are for much coarser threads.

I'll consider getting the thing made part of the challenge.

Thanks again.

I'm surprised that there's that much setup required. I guess I always thought that you just plugged a file and a blank into the machine and it spit out a part. Too bad where I work doesn't have a bit more of a full featured shop. I think they've got a brake and a couple of other things, but nothing appropriate for this sort of project. I'll double check with the guy that works there.

Thanks again.

[masraum]

I found a place that had an M30x1.5 tap for $185. Hahah.

And that's not even the right size (which I haven't found yet, M30x1.25)

So that is out of the question.

I think it's time to start thinking outside the box.

It looks like I can get the nut from Pelican for less than $15, so I think that's a better alternative to trying to find the right tap. Now all I need is a 1.25" drill bit to drill through Al (need a 1.26" hole.

[masraum]

OK, now I'm thinking that machining may not be the way to go. Maybe I can buy the nut that originally went on the end of the shaft and a gear from something, anything as long as it's big enough and have the nut welded to the gear. That sounds a whole lot less expensive. Then someday when I'm loaded I'll buy machining equipment and make my own custom base.

Ah well.

[kjb]

Why not just buy one of these things for $20 and be done with it?



/ Johan

[masraum]

Haha. Because that's not my goal. I don't actually think the pinion would fit through a paper towel roll. It's 40mm think for most of the shaft.

But I have been doing more brain storming. I'm pretty sure that at work we have a bandsaw and a drill press. I think that if I could buy the raw Al that I could shape it (not round, but maybe octogon or something) and drill a hole in the middle of it and possibly use the nut that would normally go on the end to attach it to the pinion.

[masraum]

Where would I go to buy the raw Al for something like this, a machine shop or is there a better place?

I probably need minimum 6"x6" (8x8 would be better) and either 2 pieces .75" thick or a piece that's 1.5-2" thick.

[jim72911t]

Steve, to answer a couple of your questions:

I'd make that piece on a mill, simply because it's a lot easier to find a piece or 6-8in wide rectangular stock than it is to find a round bar 6-8in diameter.

To drill the hole, I'd probably use a 1in drill bit to rough out the hole, then and endmill to interpolate the hole to the proper thread minor diameter.

As far as cutting threads, I'd use a thread mill. No way I'd pay the bucks for a tap which would most likely have to be custom ground.

(Keep in mind that I have access to tools that most people don't have lying around in the garage )

BTW, your idea of buying a nut and having it welded to a suitable base is a good one, and by far the least expensive. (Maybe this is the excuse you need to buy a welder?) It won't be as pretty, but it should get the job done.

Have fun,
Jim

[masraum]

Thanks. Yeah, I've pretty much decided against having it machined, just too darn pricey.

Anyone know where I can buy a raw block of Al?

[nota]

go to an scrap yard [for aircraft ]
for round peice of alloy
most sell for a dollar or so per lbs
and have a lot of neat stuff for a base
like a cover or gear wheel

I would press fit the center hole
just drill out or bush it down near the correct size
and force it in [HYD press or BFH]
it ain't like you want to take it apart later

[IROC]

You could do something like this so people could pick it up and play with it:

[Tim Hancock]

Just make the center hole to the size of the shaft just above the thread, then press fit or easier yet, "locktite" if you have a nice slip fit or jb weld if end up with a sloppy fit. You don't need to thread it on, it is just a display piece.

You can make this out of any type of round disk you can get your hands on. Tell me the diameter of the shaft just above the threads and how long that shoulder is and I will make you one for nothing during lunch some time.

[masraum]

The OD of the threads is 30mm and they are about 18mm long. Just above them it goes to 32mm.

I was wondering if the hole was just a tad small, like 29mm since I'm guessing that this thing is pretty hard, couldn't I just self thread the thing into the hole?

[asphaltgambler]

Emachine was not only too expensive but rude as well.

I wanted a simple metal bushing manufactured out of mild steel. After doing the CAD work and submitting it for an initial order of 100 units my cost was too $$$$ much. Plus the material cost was way out of line compared to a local guy here in Va.

I emailed the contact there and never even got a reply.

[wireedmmachine]

Originally Posted by masraum

The OD of the threads is 30mm and they are about 18mm long. Just above them it goes to 32mm.

I was wondering if the hole was just a tad small, like 29mm since I'm guessing that this thing is pretty hard, couldn't I just self thread the thing into the hole?

agree with you on the point

[wireedmmachine]

I recommend Accura machine tool co ltd for you.

cheap and high quality edm machine for moulding shop