Shop talk

Non-EMS Automotive related discussions and projects in here please.
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jharvey
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Shop talk

Post by jharvey »

I'm migrating part of a thread over to here. It was getting a bit OT, so might as well try to keep it a bit better sorted.

EssEss, sounds like you have the tools I dream about. Some day, I plan to get a Taig tools mill, or perhaps a grizzly horizontal / vertical mill. The grizzly can work as a lathe and mill, as well it has a much larger envelope than most desktop machines.

I'm curious is your CNC mill stepper based, or is it servo based? I've got a signifiant amount of machining experience. I've used big mills, and small ones like the maxnc. If yours is stepper based, I might be able to shed some like on some issues to keep an eye out for and how to prevent them.

One word of caution, If or when you lub your machine, DO NOT use silicone spay. It's a very thin lub, that won't fill in the ridges and vales in the surface finish of the gibs. This will cause spikes of force that can cause some vibration problems as well it's decreases life of the gibs. The silicone lub layer, is something like less than .0005 thick. Once it's there, other lubs will simply wipe off, rather than lub like they should. To get rid of the silicone, you have to soak it in mineral spirits for the weekend, or some similar approach. Sucks if you want to get our of the silicone issue.

A much better solution is to use the lithium (sp) grease. It has some bulk to it, and will dampen the surface finish force spikes. Also if you want to try another lub, it's much easier to change.

I'll have to look at that mach stuff when I get home. Block here at work. From what I got off google cache, it looks interesting.

This thread migrated from this thread.

http://www.diyefi.org/forum/viewtopic.p ... 2&start=20
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EssEss
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Re: Shop talk

Post by EssEss »

I use mobil vactra 2 way-lube. It's all open loop stepper, I'm not concerned w/speed and I can't remember the last time I missed a step, but I can remember the last 2 bits I've snapped off :lol:

For CAM I use sheetcam and meshcam. I'll use IronCAD/Alibre/Rhino/Turbocad for my CAD. Everything on the lathe is manual :) In fact for the most part I like doing it all manually and zoning out - pretty relaxing. someday I want to setup a little mini foundry so I can build some seriously blinged out functional shit all from scratch.
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sry_not4sale
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Re: Shop talk

Post by sry_not4sale »

EssEss wrote:someday I want to setup a little mini foundry so I can build some seriously blinged out functional [shizzle] all from scratch.
Man, don't we all!!! :mrgreen:
Owner / Builder: 1983 Mazda Cosmo 12at (1200cc 2-rotor turbo) coupe [SPASTK]
165hp @ 6psi standard - fastest production car in japan Oct 82
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jharvey
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Re: Shop talk

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I can't help but go day dream again.

http://grizzly.com/products/Horizontal- ... Mill/G3617

If I had one, I swear, I could do something really cool. I don't know what, but it would be cool.

One day, I'd really like to see it in person. The picture makes it appear it has beef in the right places, but that could just be sheet metal. Wonder how I find out where one might be near me.
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Re: Shop talk

Post by jharvey »

I thought I'd post about my reflow toaster oven. I used this as the brains.

http://www.thesiliconhorizon.com/reflow.htm

I used an $80 infrawave B&D toaser oven. Cost about $200 total. Includes both convection and infrawave elements. Works nice. I also know a fellow has modified the above with a hot air gun replacement element from sparkfun, and made a hot air SMT gun.
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jharvey
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Re: Shop talk

Post by jharvey »

About stepper CNC. EssEss glad to hear you have some good lub. I'm not sure if it's a high pressure lub or a bulk lub. I'll have to learn more about later. I mostly wanted to note the thing about silicone spray. I used it on a maxnc, and that sucked. I wanted to help share my experience to help prevent others from making my same mistake.

My other stepper comments are a bit less common. There's no problem with open loop as long as you have a reliable system, and it sounds like you are doing that with the lub. I wanted to comment about an article I read in Circuit Cellar. One of the editors was hired to do a design review of a companies CNC stepper product. The problem was that the steppers were burning up. After failure, when you would open the stepper, it had traces that were literally burnt off. The stepper only used 12V so they controller MFG pointed the finger at bad steppers. The stepper MFG claimed the steppers were fine, and the controller must have burnt them up with excessive current. This article indicated an interesting issue with a poor connector. Basically the, connector would cause a fairly small resistance. It was something like less than 1 ohm. This resistance would create a tank circuit, which would allow the voltage to multiply several times in the stepper eventually exceeding the 400V break down voltage of the PCB traces and causing the stepper to fail. Even though it was low power, and low voltage, and could not be measured via scope out side of the stepper. Moral of the story, make sure your steppers have some really good connections, or they may cause a catastrophic expensive failure.

If you don't have twist lock wire connectors that ensure full penetration, it might be worth figuring out how to get those. If the contacts aren't gold plated, and are the more common tin plated, I'd recommend a pinch of dielectric grease to help prevent mild corrosion. Here's a link about lubing tin connections.

http://www.diyefi.org/forum/viewtopic.php?f=35&t=449
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EssEss
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Re: Shop talk

Post by EssEss »

good stuff. I use no connectors in my setup, everything is directly run into my driver boards and attached via screw terminals.
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