Diy dro

So after blowing a huge wad on gear this last summer/fall, I'm hesitant to spend too much more money, but one of the things I'd like to do is get a two-axis DRO for my benchtop mill. In looking at the prices, I'm utterly appalled at what I'm finding out there. (Also, finding glass scales that will fit a Grizzly G1005Z ain't easy.)

I've been noodling with taking a DIY approach to this -- I have the coding and electronics skills to do this, and I'm currently trying to decide between using an Arduino and a Raspberry Pi (Rev B) for the project. Right now, I'm leaning toward the latter, because in-theory I could use it to run a CNC setup, too. What I am wondering about is scales.

So I have the options for going with glass or magnetic, though I'm not completely clear on the pros/cons of each, and I'm looking for ones that have either USB or serial port outputs. Can anyone provide some insights?

(And just as an aside, if I decide to do this, I'll be open souring any code I write under the GPL, and will be blogging a complete write-up of the process of building one so it can be replicated by anyone who wants to do it.)

So. Educate me on the scales -- which way to go, and where the f*** can I find them for sale online?

What framebuilding tasks are these for, and will they make you money atmo?

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Originally Posted by e-RICHIE

What framebuilding tasks are these for, and will they make you money atmo?

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Mitering, tool/fixture making, etc. From a business perspective they won't make me money directly, but it will increase my efficiency by reducing the time I have to take doing math and mucking about with backlash, etc.

Plus from the geeky perspective, it'll be a fun little side project. :cool:

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Originally Posted by DanBailey

Mitering, tool/fixture making, etc. ...but it will increase my efficiency by reducing the time

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Having seen these threads before I know that e_RICHIE (and the like) can miter up a tube with a file in about a minute...if you're really looking for efficiencies your best bet is practice through repetition. It's going to take forever for you to recoup the time, money, and energy you invest in a DRO/Milling operation given what your margins and gross sales are.

If you're looking to screw around with tools then have at it. I think machine shop stuff is awesome.

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Originally Posted by mjbabcock

Having seen these threads before I know that e_RICHIE (and the like) can miter up a tube with a file in about a minute...if you're really looking for efficiencies your best bet is practice through repetition

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I've got plenty of hand-filing repetition under my belt, don't get me wrong -- I'm just discovering that I like the less-hassle approach of a mill. And you're right -- if I were to pay $700+ for a DRO, that would be a stupid spend of money. Thus far, parted out, if I go the Raspberry Pi route mentioned above, we're talking about maybe $80, total, without the scales.

So the questions I was trying to get answered have still been left out there:
1. Glass or magnetic scales?
2. Why?
3. Where can I find them for sale with a USB or Serial connection? (My Google Fu is failing me.)

I would check on the Home Shop Machinist forum- lots of very knowledgeable folks there that should be able to help you out.
The Home Shop Machinist & Machinist's Workshop Magazine's BBS

I know a lot of people would like to run a CNC using RPi as an embedded controller but so far I haven't seen anyone make it work.

linuxcnc can work as a DRO. I would go with Mesa Electronics 5i25 and a 7i85 encoder interface. I can't imagine using a mill without a DRO, what a pain. There has been some work to get linuxcnc running on minimalist platforms like the Beaglebone. If it weren't for the interfacing, that might be your best bet. RPi is doable, but the real-time aspects are somewhat limited. Beaglebone looks like it will be running CNC machines soon with linuxcnc.

I bought plenty of encoders on ebay, but that was before the industrial guys discovered ebay, so you have to jump on any deal you can and know what you are looking for/at. A lot of surplus guys don't know how to handle a linear scale, so there is that to look out for.

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Originally Posted by DanBailey

I've got plenty of hand-filing repetition under my belt, <cut>

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I went through a geek thing too, and bought long and heavy through the 1980s. Somewhere, in another thread, I mention jettisoning most of the bigger machinery about a decade ago. At my peak, all of it helped my output grow from about 12 frames a month to about 12 frames a month. That's not a typo. But it all sure looked great in the photography shot in the studio space.

I am not sure what plenty of hand-filing repetition translates into. And I'm not saying there's only one approach to entering the profession or efficiency at the bench. But I do follow these threads and try to steer folks if it reads like they are running before they can walk. So, no - I don't know where the parts that you asked about are sold for affordable prices. I'm just not sure they can or will replace experience or intuition no matter what the cost.

These 1s and 0s can give off a strange vibe so I'll add - no snark intended with this reply. We're all here to help and include, rather than exclude.

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Originally Posted by e-RICHIE

no snark intended with this reply

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I totally agree and should have added this.

The most helpful thing I ever did was to go visit Dave Kirk's set up back in the day. The number of ingenious procedures, tools, and techniques forced me to realize that a lack of tooling may seem like a limitation, but it ain't. You listed on your website that your intention is to build frames for a living...paying a mortgage and all.

From what I've seen, some of the mist successful guys (defining success in terms of making a living at the handbuilt thing-Sachs, Kirk, Garro) are those without the machine intensive shops. Of course those guys also have a relatively singular bike that they focus on and I see you're looking to make the full gamut from fat bike to road bike. That's fruit for a different conversation.

I have not ordered from the link below yet but am looking into it for my lathe. I'd guess it would be hard to find scales for much less than they sell the whole package

http://www.thedrostore.com/

I have ordered and installed a Korean Jennix DRO on my mill a few years ago with no problems.

Jenix dro

Glen
back40 bicycleworks

Another solution is to adapt modified calipers and use their displays. It will cost you less than $100, and you will save all the development time... I found that for my tooling and framebuilding this setup is more than enough...
Just 2 things: it seems that these kind of scales are too slow to work with a DRO (refresh rate) and they don't like oil/cooling fluids...
http://farm6.staticflickr.com/5089/5...9f3f11776c.jpg
Cheap DRO... par Edelbikes, sur Flickr

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Originally Posted by DanBailey

I've got plenty of hand-filing repetition under my belt, don't get me wrong -- I'm just discovering that I like the less-hassle approach of a mill. And you're right -- if I were to pay $700+ for a DRO, that would be a stupid spend of money. Thus far, parted out, if I go the Raspberry Pi route mentioned above, we're talking about maybe $80, total, without the scales.

So the questions I was trying to get answered have still been left out there:
1. Glass or magnetic scales?
2. Why?
3. Where can I find them for sale with a USB or Serial connection? (My Google Fu is failing me.)

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Probably not what you had in mind, but I put some basic digital scales on my benchtop mill after realizing that a real DRO would cost almost as much as the mill itself,

http://farm8.staticflickr.com/7192/6...b98a2cfd5c.jpg


http://farm8.staticflickr.com/7195/6...f143ef2903.jpg


http://farm8.staticflickr.com/7260/6...fee89a067c.jpg


I got them from Grizzly. They carry several different length's, here's the 24" one, T24362 24" Stainless Steel Remote Digital Readout. These are the heavier duty versions with the stainless beams, as opposed to the cheaper versions that Grizzly also sells which are meant more for woodworking.

Been using these for about 9 months now and they've held up well to cutting fluid and chips. Just throwing this out there in case it helps.

Alistair.

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Originally Posted by mjbabcock

Of course those guys also have a relatively singular bike that they focus on and I see you're looking to make the full gamut from fat bike to road bike. That's fruit for a different conversation.

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Although I agree that often the toys and tooling does little for the bottom line there are also a large chunk of "us" who like to be able to make a large range of bicycle frames or items outside or in addition to bicycles. Working with metal and tools is my personal passion along with the business end of things and therefore I justify the ability to go out to the machine shop and be a knob or make a knob.

A Grizzly G0704 and most of the tooling you need can be had for $2K or less and frees you to do a lot of different bikes and is really useful in general. Of course, that's a lot of practice bikes tied up in a mill. I can miter just about anything on a bike by hand, but recently I was trying to make a segmented fork and ran out of patience on the crown pieces. Curved tubes start to push the limits of my hand mitering capabilities. A mill would be nice for those. I think the ability to miter by hand is probably overblown.

If you are just going to miter on a mill, a DRO is probably something you can skip for now.