Re: [GrizHFMinimill] Re: My $106 HF Mini-mill 3 axis DRO [6 Attachments]

[Attachment(s) from Charles@ideasdevised.com included below]

Hello everyone,

I have been watching these posts for a while so I will give you some photos of what I did with my HF mill several years ago. First off I was disappointed that the mill I bought had 1/16th travel per revolution of the hand wheel and with a half thou. in the last increment on the hand crank it got confusing pretty darn quick. So being frugal as I am plus the prices of dro kits back then were much higher, so I went down to my local HF store and bought 3 digital calipers and ground the jaws off and mounted them on my mill. I also had to take the reading head part of the caliper apart and mount it to an aluminum plate. It has worked great for many years now and couldn't live without it. The accuracy is good enough for my work which includes bolt circles to match other parts that I didn't make. I do have a CAD program and also have made some contours and establish all my X,Y, Z coordinates with the CAD so I couldn't live without that either.

Also my machine came with no reverse, so I just put in a dpdt relay inside the switch box and a spdt switch and that worked good for about a year until one day I hit the reverse before the machine was at a dead stop so it blew out the speed controller. With that controller smoked out I started shopping and found the original replacement was way to expensive and the fact that I would probably blow it out the same way. So I jumped on eBay and found a KB controller for about $35 if I remember correctly. I think it sat in a shop for 30 years and was never used. Although it is very old it is still great technology. Now I can hit reverse at full speed ahead and it will stop the machine and go into reverse. It is made to do that. I could also make it brake if I wanted but there is really no need in what I do. In the photo you can see the box I made room for the manual that came with it. I also added a small fan and I think the controller also controls the fan probably an overkill but I just didn't want to take any chances with it getting overheated.

Here are the photos of the whole shebang! :)

Charles Anderson

www.IdeasDevised.com

From: Gary Liming <g_liming@yahoo.com>
To: "GrizHFMinimill@yahoogroups.com" <GrizHFMinimill@yahoogroups.com>
Sent: Sunday, December 4, 2011 8:42 AM
Subject: Re: [GrizHFMinimill] Re: My $106 HF Mini-mill 3 axis DRO

Thanks for the description of the plastic fab. I am right behind you - I just started making DRO covers out of aluminum, and I plan on making a feed drive.

The feed drive - you using a drill or a windshield washer motor for that? I've been eyeing this cheap HF 12v drill I have - it has plenty of torque and includes a reversible power controller for variable speed already there.

I agree about accuracy - being told emphatically that I need to spend $1K or more on some DROs for a used Chinese mill whose basic accuracy is in question anyway is just snobbish. I used to work in a physics lab who had guys who who would laugh (to themselves) at some of the tighter tolerances being described in this thread, but I think they would not be so crass about how they said it. Its just about what is needed to accomplish a particular job. For many jobs, these things work fine.

From: Rick Grimm <grimmrlg@yahoo.com>
To: GrizHFMinimill@yahoogroups.com
Sent: Sunday, December 4, 2011 9:07 AM
Subject: [GrizHFMinimill] Re: My $106 HF Mini-mill 3 axis DRO

The 1/8" plexiglass was heated with a hot air gun and formed over a piece of 3/4" thick wood and pressed into a channel form made up with 2x4s clamped to a piece of plywood spaced 1" apart, then sawed to final width on a table saw.

I'm currently finishing up an X-axis variable speed drive that I'll be posting shortly, total cost $50.

As for the accuracy of these DROs, I've already made several projects relying soley on these for laying out circular bolt patterns with +-.001" toleances and fitup has been perfect. I guess for a HF quality mill with its own limitations of accuracy, these devices are a perfect match. If I wanted to maintain .0001" tolerance I'd choose a more expensive machine.

--- In GrizHFMinimill@yahoogroups.com, Gary Liming <g_liming@...> wrote:
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> Very nice job, Rick. I like the bent clear (acrylic?) covers. What technique did you use to do that?
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> From: Rick Grimm <grimmrlg@...>
> To: GrizHFMinimill@yahoogroups.com
> Sent: Thursday, December 1, 2011 9:13 AM
> Subject: [GrizHFMinimill] My $106 HF Mini-mill 3 axis DRO
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> I recently purchased a HF mini-mill and my first series of changes were to add 3 axis DRO, pulley drive, and gas spring. I purchased 2 12" and 1 6" iGaging DRO remote readout scales from Grizzly, with shipping it came to $106. I followed some of the previous posters installs with some changes to fit the HF mill, for example the X axis hangs out on the left side of the table instead of the right.
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> Rick Grimm
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