NGC another question for the machinists

[Canuck750]

I am considering adding a DRO, probably a three axis to my small knee mill (40+ year old Tiwanese machine). Anyone have some experience / advice on purchanisng the Chinese kits on Ebay, most seem to be the same and originate from Shenzen China:

https://www.ebay.com/itm/384518307227?hash=item598713bd9b:g:B10AAOSwLdJcj2F9

Given my machine is quite small it looks like a three axis kit will come in under $300 US

My setup, small machine that came with a huge vice but it works for the small things I may attempt



I added a cheap Chinese (appx $200) X axis power drive this week, it was supposedly universal fit, .... after making an adapter bracket, an additional bushing for the lead screw axle, machining the brass drive gear key slot and extending the lenght of the end of the lead screw, yeah it was universal...

[Mike Tashjian]

I did both my mill and lathe about a year ago with sets from ebay.  The scales can be shortened by taking them apart and cutting the body and glass scale inside.  You will probably end up making stops and and mounts.  It is a giant step forward so well worth the effort.  Only having been using the scales for a year or so there have been no issues with them.  I opted for the 2 axis for the lathe and three for the Mill/Drill.

[Canuck750]

I did both my mill and lathe about a year ago with sets from ebay.  The scales can be shortened by taking them apart and cutting the body and glass scale inside.  You will probably end up making stops and and mounts.  It is a giant step forward so well worth the effort.  Only having been using the scales for a year or so there have been no issues with them.  I opted for the 2 axis for the lathe and three for the Mill/Drill.

Thanks Mike,
Good to know you found the investment is well worth it.

[Mike Tashjian]

I took a couple pictures of the DRO I have and funny that I adapted a table drive too.  Cranking gets old.

[pehayes]

I have a 3-in-1 lathe/mill/drill machine.  Crude, but serves my needs.  Years ago I added a DIY kit, the DRO350 from Shumatech.
http://www.shumatech.com/web/products/dro-350
I used what are known as 'Chinese Scales' for the sensors.  I've never had any real problems.  The system seems to be more advanced now and with better kits.

Mine doing a squared up filler plug helicoil on a Guzzi 5-speed:




Patrick Hayes
Fremont CA

[John A]

I am considering adding a DRO, probably a three axis to my small knee mill (40+ year old Tiwanese machine). Anyone have some experience / advice on purchanisng the Chinese kits on Ebay, most seem to be the same and originate from Shenzen China:

https://www.ebay.com/itm/384518307227?hash=item598713bd9b:g:B10AAOSwLdJcj2F9

Given my machine is quite small it looks like a three axis kit will come in under $300 US

My setup, small machine that came with a huge vice but it works for the small things I may attempt







That’s an attractive price. I’m contemplating the same thing for my mill, it’s a 40 year old Taiwan with a 3/4 horse motor. It’s not seen much use, the guy I bought it from got a brain cancer. He had a great sense of humor and used to go to the Iowa rally but had a Valkyrie. So I’m wanting a DRO and I’m collecting stuff for power feeds. I scrounged an electric wheelchair that mold had gotten into so I have dc motors with gear boxes to use but haven’t started yet. It’s a learning curve for me so I’m glad to see this posted!

[Canuck750]

I took a couple pictures of the DRO I have and funny that I adapted a table drive too.  Cranking gets old.

Thanks for posting pictures of how you mounted the scales, very helpful.

Thanks Patrick for the link

Jim

[John A]

I took a couple pictures of the DRO I have and funny that I adapted a table drive too.  Cranking gets old.










Mike, in the first pic there is a vertical rod behind the hand wheel. Is that a stay for the head to stay in position as you raise and lower it? I need to make one of those. What is yours anchored to at the bottom?  How does it work? I don’t expect mine to be holding positions super accurately and I haven’t figured out how I will do it. Any suggestions?
My mill looks very similar to yours, same company on the name plate. Probly different years. I’m still trying to not wreck my tooling as I figure out what not to do with it. Edit: I see now in the pic you made a clamp for the main support. I think I will make one similar….what did you do for the slider?

[jrt]

I put a 2 axis kit Newall kit on my Bridgeport, then later added a cheap 'caliper-type' mount for the z-axis on the quill.  Works great and makes up for the wear in the gibs on my old mill. 

[Canuck750]

I put a 2 axis kit Newall kit on my Bridgeport, then later added a cheap 'caliper-type' mount for the z-axis on the quill.  Works great and makes up for the wear in the gibs on my old mill.

Can you please explain what a 'caliper type' scale is?

[Chuck in Indiana]

Can you please explain what a 'caliper type' scale is?

The guts from a 6" electronic caliper.

[Canuck750]

The guts from a 6" electronic caliper.

duh! I should have figured that one out

[pehayes]

Regular 6" "Chinese Scale" calipers can have their jaws cut off.  But, the metal is VERY hard and nearly impossible to drill if you need to make screw mounting.  Cutting is easier with a thin Dremel abrasive wheel.  You have to be careful not to overheat the metal and loosen the glued-on capacitive measurement strip.  Meanwhile, there are numerous suppliers that will sell you just the beam and reader/sensor without any jaws to remove.  You can get them in various lengths as short as 2" and as long as 3'.  I use 3 of them on my lathe/mill.  I have a 4th one which came from a caliper and I cut off the jaws.  Won't be doing that again!  I can easily get some pictures of a beam and mounts if anyone wishes to see.  There are standard plugs and wires to carry the measurement signal back to a remote display.  I use the now obsolete DRO350 from Shumatech but you can make newer, competent versions from their kits.

Here's an Amazon beam at 29"

https://www.amazon.com/0-600mm-Scale%EF%BC%8CDigital-Scale%EF%BC%8CLCD-Scale%EF%BC%8CDRO-Machines/dp/B08DY9R3ZD/ref=sr_1_21?crid=30TCY97DHB7C5&keywords=dro+scale&qid=1644110296&sprefix=dro+scal%2Caps%2C143&sr=8-21

The "Chinese Scale" beams are not as reliable or accurate as "glass scales".  But I'm not making watches, just spacers, bushings, tools for Guzzi work.  We all know how 'precision' the factory is.

Patrick Hayes
Fremont CA

[Canuck750]

Thanks Patrick, good information

Jim

[John A]

Yes, thanks Pat, that link opened up a bunch of possibilities.  The question I have is that on my Taiwan mill when you raise and lower the head it gets unclamps to the main post and will float free and loose alignment. The customary fix is  to make a stay to help keep it from moving . With a dro setup how necessary is the stay? I’m assuming with a two axis dro it would be easy to get it back to the spot you were in. Is this correct?

[pehayes]

I’m assuming with a two axis dro it would be easy to get it back to the spot you were in. Is this correct?

Well, that's the whole idea.  Returning to a predefined spot to perform a second machine function.
I presume that ALL DRO systems will allow for both 'absolute' and 'relative' positioning.  Once I define and locate a specific point, I can temporarily set the DRO to ZERO/ZERO relative display.  Move anywhere you wish.  Then return to the same zero/zero to do more work.  I often use a program feature called 'bolt circle'.  This feature allows you to define any number of  holes at a specific radius.  Once the pattern is defined by a few key strokes, you locate on the zero/zero center point.  Now invoke the program and your display numbers suddenly change.  Dial in zero/zero and you are now hovering at the precise point to drill hole #1.  Invoke hole #2 and  the numbers change once again.  Simple, just dial in zero/zero and you are at the point to work on hole #2.  Go around the circle this way multiple times.  Spot drill - pilot drill - main drill - tap - countersink.  You are constantly just dialing in zero/zero as displayed by the DRO.  Useful to make fixtures like this:



Fixture for rebuilding tail lamp reflector on the EV/Jackal.  Fixture is utilized in my lathe but was produced using bolt circle program on my mill.

Patrick Hayes
Fremont CA

[John A]

Thanks, Pat. It dawned on me as I was looking at the dro’s and I haven’t played with ‘em much, last time I looked they were expensive. I’d best get some, thanks for the link, even if I don’t buy from azon it’s a good place to look!
Edit nice work on that fixture, I would have had to lay it out with machinist dye. Sometimes I’m thick as a brick…

[sidecarnutz]

Wow. I have a old Shoptask XT97 I bought new in the summer of 97. It was a great tool for it's cost. So good value. But now the lathe motor is burned up. I did give it good use over the years. Never updated with DRO due to limited budgets.

[jrt]

Thanks Patrick-  I missed this earlier. 
I specifically used this one:
https://www.amazon.com/iGaging-Digital-Mounting-Bridgeport-Fractions/dp/B07SPW1M47/ref=sr_1_3?crid=3S68G5YPL5CKD&keywords=z+axis+dro&qid=1644353298&sprefix=z+axis+%2Caps%2C76&sr=8-3

but it was $20 when I bought it.  It is overpriced (by a lot) at $100.

One other thing that I added to my mill that I love, love, love is a light ring.  Because so many people are now working from home, there is a whole industry devoted to improving video.  You can buy an inexpensive light ring, mount it around your quill and bing!  light directly on your workpiece. 
I use this one (Guzzi Content:  $12- splurge and get the gooseneck): 
https://www.amazon.com/gp/product/B09264D3Z3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

I like it because the diameter fits the quill-  a lot of these rings are much larger. 

[Canuck750]

I bought a 3 axis DRO, glass scales kit off Ebay, from China, arrived in under 10 days, took a couple days to install, Its going to be great!

https://www.ebay.com/itm/384518307227?var=652609057569  under $300 USD delivered

I was surprised to see how accurate the hand wheels were conformed by the DRO, one full turn of my X or Y aixs is 4mm on the hand wheel and the DRO is almost bang on, reading 3.995



I did not underhang the Y axis reader, I may change that out if I find too many chips getting into the scale but I think it will be ok when I replace the way cover with a new rubber sheet



I had to cut out the chip tray to allow the power feed to run full left, not pretty but it works, copper pipe slit and slipped over the cut off tray

[dsrdave]

Once you get used to it, you’ll wonder how you got along without it.  Makes life, and accuracy so much easier!!

[Chuck in Indiana]

if I find too many chips getting into the scale

One chip can do it. <shrug> Unless they are different than back in the day, it's a glass scale etched with lines every half thousandth. One scratch and the computer loses track of how many lines it has counted.
Amazing what you can get for $300..  That kind of stuff used to be expensive.

[Canuck750]

One chip can do it. <shrug> Unless they are different than back in the day, it's a glass scale etched with lines every half thousandth. One scratch and the computer loses track of how many lines it has counted.
Amazing what you can get for $300..  That kind of stuff used to be expensive.

Good point! It easy enough I suppose to flip the Y axis scale and reader over and make a hanging bracket for the reader. May as well fix it now.

The cost of tech is getting stupid cheap. Twenty years ago I paid about $30K for a half decent large bed printer for architectural drawings, the cost is now half or less and the quality of the print images is amazing.

[Chuck in Indiana]

May as well fix it now.

Be careful with compressed air around those scales for the same reason. You really don't want to blow a chip past that seal. That said, I've had no problem in ..uhh.. 30 some years.