Lathe Tool Grinding Helper

[randyc]

This morning I found a set of detailed instructions, including photos, in my e-mail explaining how to disassemble/reassemble the reading head and what is likely to be wrong with it.  Took less than five minutes to fix the scale.  And since I had it partially disassembled, I went ahead and cut it down.

There are various methods of doing this posted online and I decided to use a fairly conservative technique.

Note that the most daring thing that I saw, and he posted photos, was a brave man who just decided to bandsaw through everything at once, aluminum, flexible seal and glass.  I couldn't imagine how that would accomplish anything except totally destroying the scale but apparently it was successful.  However that was just a little too bold for me - wonder how the tips of the bandsaw blade held up.

My first step was to mark the length and scribe lines all the way around the aluminum extrusion, marking where the glass scale was with relation to the extrusion so that I could stop sawing just short of it.

Cut all the way around the extrusion stopping at the marks for the scale:

   

Some folks just broke the glass scale to length, some sawed it off with a diamond wheel in a Dremel tool, I found that neither of these methods were appropriate.  The glass scale could not be removed from the extrusion and it must be cut off about an inch INSIDE the end of the extrusion so the glass was inaccessible to either technique.

I couldn't cut the extrusion completely away from the glass because there are two ledges in the extrusion that hold the glass in place - can't cut through those without cutting the glass.

Fortunately I had a diamond blade in a small coping saw for just this type of rainy day, so a few minutes work and the scale was cut.  I had some worries about the heat generated by the Dremel/diamond wheel anyway so I felt much more comfortable with hand-sawing.  The blade, if interested, came from the HF store.

   

Now the nasty part, removing the glass for about an inch behind the end of the extrusion.  No matter how one decides to do this, safety glasses, while should always be worn, are REALLY important when dealing with glass.

I'd read that this could be easiest done with a pair of end nippers, just nibbling away at the end of the glass slide until the correct length is achieved.  Unhappily, I had the same experience as another fellow on the internet did - the glass cracked diagonally for about two inches when I tried to nip it.

BUT, as the other person said, ugly as it looks, it's no big deal since the reading head can't go all the way to the end of the extrusion anyway and the flaw can't be seen when the end cap is screwed on.

Next step was to re-drill and tap the holes on the end of the extrusion.  I did this on a light, floor model radial drill press with the table adjusted parallel with the spindle.  I used the end cap as a drill guide and the two woodworking spring clamps held it securely aligned with the exterior of the extrusion.

   

The screws were metric, around 2.0 mm and I don't have any metric taps that small.  I have 2-56 taps but didn't have any 2-56 screws x 3/4 long, which were required.  So I drilled the holes about .010 undersize and self-tapped the metric screws into the extrusion which is dead soft aluminum - worked fine.

After drilling and blowing out the extrusion thoroughly (I figure some of the shavings from the bandsaw had to be inside) the end cap was reinstalled.  Next step - and the most tedious - will be devising and making mounting provisions.

[f350ca]

Your a brave man Randy.
Out of curiosity what was wrong with the scale?

[randyc]

I thought that hand-cutting the glass with the diamond blade in the coping saw frame would be safer than the other methods, considering the tremors in my hands.  It wasn't really bravery, ha-ha-ha, just a matter of minimizing the risk of failure.

I sure wish that I'd done more research and found that custom lengths were readily available 

The reader head was a strange looking mechanism and the problem was even stranger.  There were a couple of polished balls (eg ball bearing types) inside it, one of which was fastened to a torsion spring.  Looked like a round sinker hooked to the leader on a fishing tackle rig.

The normal seat for the ball was in a spherical pocket from which it had slipped.  The fix was to hold the ball into the socket while keeping the circuit board perpendicular to the reader head and slipping the assembly back into the extrusion.  It took three or four tries but not much time at all.  The seller was great about responding quickly with detailed advice !

[randyc]

OK, next off-topic diversion from the diamond grinder and regarding the Chinese DRO.

I need to devise and make mounting provisions for the scales and the display.  Because it was cold in the shop last night, instead of measuring all of the parts and the areas of the mill to which they will be attached, I relaxed in my warm living room.

From the fairly complex display symbols and the length of the operator's manual that accompanied the DRO, I thought that I might as well start reading the manual and get a head start on using the DRO.  After about five seconds I realized that the only way I'll learn how to use the device is by experimenting.

Here's a scan of one page - and it is typical of ALL of the pages, LOL:

   

   

I sincerely hope that you can read all of this, starting with "the god of the earth..."  because it is HIGHLY entertaining 

[f350ca]

Now thats funny !!
Is that the product of Google translate?

Was really surprised at the proper English in the manual that came with mine, not that I read it. Had to figure out how to use the bolt circle function and a couple of other things, long winded but understandable.

Haven't taken one of the Chinese scales apart yet, had to disassemble one of the Fagor units on the lathe to fix a break in the cable. The balls and spring might be part of the price differential, the Fagor one uses the tiniest ball bearings to guide the read head in the channel.

[randyc]

My presumption was that the translation was done by a Chinese human but of course they may have used Google to do it.

It's not completely bad news, however.  I did a search for translated versions of DRO manuals and came up with a half-dozen hits.  Searching through the PDF's, I found one with an identical front panel.  The manual is intended for CNC applications and is mostly about the programming language.

But I think that I can get enough out of it to figure out the desirable functions and it IS in comprehensible English 

Yeah, what you say about the construction versus price differential makes perfect sense, Greg.

[randyc]

My word, this gets more convoluted with every action.  I saw that Grizzly sells the exact same DRO system, down to every last bracket and screw.  Unhappily, instead of the $200 that I paid on the eBay store, they would like about $1,000.  So much for reduced costs by eliminating the middleman, as is claimed in their ad for the DRO.  (Oh yeah, they also claim that this system was designed for them.)

But their rip-off pricing is of no concern to me for now, what I was interested in was a user's manual of course !  I had high hopes that someone had translated my amusing document into something useful.  Every one of their DROs has a PDF of their "manual".  Every one of the "manuals" is a set of instructions on how to mount the DRO.

No operating instructions.  

[randyc]

After sitting on my butt watching it rain (and watching four lightning strikes less than 1/2 mile away) for about a week, I finally got in motion again.  No not on the diamond grinder but hopefully that starts tomorrow.

BUT I did get the DRO installed and it works fine although I don't yet know how to use it for anything except measuring the travel of the table, LOL.

Here's the installation - note that the weird appearance of the digital display is because the plastic protective cover is still on it.  This is a pretty cool system for $200 and it comes with a LOT of stuff for mounting, 90% of which I didn't use because I wanted it to mount on my tee slots rather than drilling a bunch of holes.

   

[Pete O]

At that sort of money, it will be difficult to justify NOT installing a DRO when my U2/BP marriage happens. Although it will probably translate to about double what you paid there by the time I land one here.

[randyc]

(01-27-2018, 08:29 PM)Pete O Wrote: At that sort of money, it will be difficult to justify NOT installing a DRO when my U2/BP marriage happens. Although it will probably translate to about double what you paid there by the time I land one here.

Pete, that was exactly my feeling.  I've dealt with dials on machine tools since - well, a l-o-n-g time.  As a hobby machinist, I didn't think that I could justify the expense of a DRO.  But a friend continually nagged me and when I saw that price, WOW, couldn't not buy it !  Do you think it would really cost more for you (it's not like you're any further from China, right) ?

I was not enthusiastic about the installation process since I didn't want to use the included collection of brackets and multiple types of hardware provided.  But I probably have a total of five hours into it even though it's a non-standard installation.  (I think that I made an unnecessarily bigger deal of the process than 99% of people who buy these things !)

Incidentally this is a drawing of the diamond grinder as envisioned at completion.  Note the "EPA-friendly" vacuum connection, LOL.  The panel with power switch, fuse holder and AC power socket is not shown - it is attached between the two front legs.