Author Topic: Dah Lih DL-VHR-GIF mill - a journey of discovery  (Read 2927 times)

Offline Joco

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Dah Lih DL-VHR-GIF mill - a journey of discovery
« on: October 25, 2018, 11:55:35 AM »
I have a new toy .. err .. tool ... yes TOOL.  I've been having fun with the BF20 but that is now in bits under going a CNC conversion and I wanted something that was a bit chunkier, a bit more solid, manual and yet not OTT.  So after a rash moment by SWMBO where the magical words "yes you can get another mill" were uttered I pounced.  Thanks to some excellent snooping by a good mate Bruce I have become the owner of what seems to be referred to as a "Small/Medium Knee Mill".  A Dah Lih DL-VHR-GIF. Compared to a BridgePort its definately smaller but for my workshop I think will work well.  It does have a few nice features: 6 speed power feed on X axis along with rapid, one shot oiler, horizontal and vertical milling spindles, and flood coolant.  This is an old mill but seems to be in reasonable condition with the previous owner getting the table reground and the completely redoing the bearings in the spindle.

I have some light restoration work to do with surface rust removal, some new paint and a few handles and the like to be replaced/fixed.  The biggest challenge will dealing with THREE motors in it all 3-phase.  I think I will end up with a stack of VFDs on the wall or hidden in the machine somewhere.

Anyway the beginning of a jouurney as I learn this vernerable old tool.


« Last Edit: October 25, 2018, 11:59:46 AM by Joco »
James
Wellington - NZ

Offline b.lindsey

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #1 on: October 25, 2018, 12:19:55 PM »
Congrats on the new mill Joco. Looks to be a solid machine and should offer the greater rigidity you want. A little paint, polish and TLC and she'll be good for another 50 years!!

Bill

Online Kim

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #2 on: October 25, 2018, 05:40:47 PM »
Looks like a pretty substantial mill!

Does it use R8 collets?  Or something else?  And did you get it with lots of extra tooling?

How fun!  A new toy!
Kim

Offline Joco

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Tapers, holders and motors
« Reply #3 on: October 25, 2018, 09:28:54 PM »
Another pic of stuff that came with the mill.   There are a selection of holders here for face mills, end mill, jacobs chuck, ER40 and ER of size to be determined.

There are two distinct styles of taper fortunately both styles are a 7/24 taper.
I have
- NT30 (or more correctly NMTB #30) tapers which I suspect is what the defaut is for this machine
- BT30 tapers (the ones on the right). Given these need an extra spacer on the drawbar that implies that while they fit they are not the style intended for this machine.

The other little joy from last night was the discovery of a 3rd motor tucked away in the back of the beast. In hindsight I should have expected it.  This motor is what drives the horizontal arbor. So another complication to the electronics.  I could certainly replace it with a single phase motor and maybe that is the better option. However at the moment I feel reluctant to walk away from the original 3 phase motor.






CHeers,
J.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #4 on: October 26, 2018, 09:45:11 AM »
Had a close look at the horizontal arbor this evening and its clearly a BT30 taper and that arbor is absolutely original to the mill so BT30 is the originally intended taper.  :-)

James
Wellington - NZ

Online Jo

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #5 on: October 26, 2018, 09:59:48 AM »
Have you thought about keeping the three phase electrics and just buying a three phase converter? I have been very happy with my (big) rotary converter.

Replacing electrics with VFDs can be painful especially if there are power feeds and interlocks etc. You know where you stand with the original electrics and the manufacture provides a wiring diagram  :)

Jo
Usus est optimum magister

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #6 on: October 26, 2018, 10:16:20 AM »
Jo - a suitable 3 phase converter in NZ is going to set me back about half the price of the mill (2000 - 2500 NZD).  Where as I can get a VFD for each motor landed at ~$130 each. Having said that I think I might be able to get away with only 2 as I can never run both horizontal/vertical motors at the same time. So I should be able to use some simple relay setup to create the needed isolations.  I have an electrically trained mate who gets this stuff way better than I do to help ensure I don't screw it up massively.   :zap:

The other benefit of the VFD is I get some really nice control over speeds and forward/reverse that the original electrics setup just can not match.

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #7 on: October 27, 2018, 07:55:56 AM »
Started cleaning things up today.  Got all the old swarf cleaned out, attacked the surface rust with some stainless syteel wool and Inox.  I removed rubber ways covers on the Z and Y as they were getting pretty tatty.  I'm thinking of replacing them with the BBQ liner that copes with the heat well. Otherwise it will need to be a trip to Skellerup to get some new rubber.
I'm also going to have to get some etching primer and a pot of the battleship grey used so I can start touching up some of the exposed redish primer as well as repaint where things have chipped away.

Other litte jobs done include:
[1] Working on the draw bar so that it has a nice sliding fit where as it was sticking badly before.  Now it can easily be removed and a space put on to allow the use of the NT30 tool holders.  I have a pic here showing the BT30 ER40 collet chuck in place.

[2] figuring out of the X axis DRO scale was faulty or of it was the reader that had died.  Looks like it is the reader as when I put a reader from another scale in it everything seemed to work fine.  Time for a replacement order from AliExpress.










CHeers,
J.
James
Wellington - NZ

Offline b.lindsey

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #8 on: October 27, 2018, 02:52:22 PM »
Slow tedious work, but it's looking good already.

Bill

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #9 on: October 31, 2018, 09:47:43 AM »
VFD's turned up today.  These are neat little units that take 230V input and provide 380V output.  Just right for dealing with single voltage 3 phase motors.  I've done a temporary connection after checking and tweaking ever so slightly the VFD settings.  These videos show me mucking about really, just trying a couple of different ways to run the motor and see how it went.

At the moment I do not have DC braking on.  Once I get that setup it should stop stop much faster.  I do need to determine if I can and should use a braking resistor.  Given this is a mill I don't see a lot of built up energy in the spinning parts, at least not like a lathe with a spinning work piece on it.

Starting at 25Hz, using the dial to push to 60Hz then hit the stop button.

Starting at 25Hz then using the forward/reverse button and finally stop button.

Starting at 0Hz and using the dial to bring the Hz up to about 49Hz then back down to 0Hz.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #10 on: November 02, 2018, 11:33:49 AM »
Some further testing and a significant improvement in the start and stop speeds.  Half the battle is deciphering the unclear manual. The next signifncant stage will be expanding the existing electronics housing to accomodate the VFDs (one for vertical spindle  and one for the horizontal) as well as the static converter electronics. Hopefully some progress pics from that after this weekends efforts.

Anyway, very short video of how quickly things spin up and down under VFD control.
James
Wellington - NZ

Offline Larry Sw

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #11 on: November 02, 2018, 06:57:14 PM »
Nice looking, and sounding, Mill.
Does it have an Outboard Support for running milling cutters on a long arbor ?

Larry S
Fort Wayne, IN  USA

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #12 on: November 02, 2018, 08:04:08 PM »
Larry,

Yes it has a support on the back of the top "ram". To use the horizontal milling function you swing the ram around and setup the horizontal arbour.  This pic came from the garage of the previous owner, hence why the background is not consistent with mine.

Cheers.

James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #13 on: November 09, 2018, 05:37:18 PM »
I’ve made some progress but it’s really temporary as I’m waiting on a number of parts to arrive before I can make things final. I made a little video just to show what I had gotten working and setup. I dont clam to be videographer so bear with.  :old:

I also did some tramming on the head using a DTI with 0.01mm markings. Front to back is bang on. No movement. Left to right i got to under 0.01. Given the level of movement in the needle I would estimate slightly less than 0.005. Pretty happy with that.

I did do a review of the wiring after this video amd fix a few bugs. Where things should have been running slower than they were in the video.  But you’ll get the gist of things.  :popcorn:

Cheers,
J.

James
Wellington - NZ

Offline Ye-Ole Steam Dude

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #14 on: November 09, 2018, 06:39:09 PM »
Hello J

Very nice machine and a neat video.

Have a great day,
Thomas

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #15 on: November 13, 2018, 09:10:48 AM »
Some more fettling and improvements.

I was finding the Z axis really stiff on going up and when letting it down it would "judder".  I had thought i had too much slop and it was locking on the way down.  Actually it is much simpler than that, the gib screws were too tight.  It was the first time I had looked at them.  After a little tweaking the Z axis is nice and smooth.

Next challenge was Y axis. Quite a bit of excessive slop here, about a 1/4 turn of the wheel and when milling with heavy cuts I could feel the give when the end mill grabbed and moved the table a little.  Definitely not ideal.  So I went hunting for the adjustment (oh please let there be adjustment).  And I found this arrangement:


Now this image is post adjustment. Imagine this with only the top M6 screw and with no clamping washer. So first off another M6 screw and two custom clamping washers whipped up on the lathe.  Then some tweaking by backing this nut off then re-clamping the M6 screws to drive a little loading on to the leadscrew.  Net effect is a really smooth wheel action and a backlash of 0.04mm.  I think I can live with that.  :whoohoo:

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #16 on: November 19, 2018, 08:31:16 AM »
Okay I'm getting lazy in my old age and doing these videos shows way more than a set of static pictures.

What we have here is ...

[1] Video showing the new chinese sourced digital tachometer in operation against the high gear.  If anyones interested I can take some photo's of how I have the sensor and magnet setup in the head.

[2] showing the tapping speeds and the speed of stopping and reversing when under VFD control.  I've used this setup to power tap M10 into 6mm steel with no worries at all.  I suspect it will do a lot thicker and at some point I'll dig out some 12mm scrap and try it on that.

Cheers,
James.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #17 on: November 21, 2018, 07:05:09 AM »
The learning continues both in how to set up the VFD but also in how to use the mill.   I setup on Gear 2 which had a name plate top RPM of 700.  It was actually spinning out about 800 rpm.   For drilling with a 6mm pilot hole and then to dialling it back a little for the M10 tapping drill size. Then pulling things back to the low gear belt and running at 25% of max frequency (15Hz) for the tapping.  Which gave about 140 rpm.  Once I have everything setup with the final parts I should be able to get down to between 5-7 Hz, so about 60-70rpm.

The key learning with the current setup I have which is 8 preset speeds from 100% down to 12.5% is that I can have custom ramp up and ramp down rates.  So for the two bottom settings I have it decelerating at 60Hz/sec.  This means the spindle stops FAST, or for that matter moves from forward to reverse pretty dang fast as well.  Where as for the higher speeds I have a more leisurely 30Hz/sec rate which just keeps things less stressed on the motor.  It still stops in ~2 secs.

Have a look at the video of power taping for M10 x 1.5 into 16mm steel.  Pretty cool and quite fast.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #18 on: November 25, 2018, 07:24:53 AM »
In the process of building a tailstock support for a rotary table i got to power tap M10 x 1.5 holes through 30mm of mild steel.  This 1HP motor on low gear (not a back gear) under VFD control just munched trhough it at about 80-100 rpm.Not single sign/sound of strain.   :whoohoo:

James
Wellington - NZ

Offline Admiral_dk

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #19 on: November 25, 2018, 09:39:44 PM »
Sounds like you got yourself a very nice mill after the mods  :ThumbsUp: congratulations  :cheers:

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #20 on: November 27, 2018, 08:14:39 AM »
I thought I would post some pics showing how I had setup the digital tacho on the mill. It's not particularly special I guess but just in case someone finds it useful.  It seems to be working well and in the end allowed me to mount all the parts without having to glue anything to something that would require destructive removal when wanting to get back into the spindle assembly.

Overall view looking down into the belt housing.  You can see the collar that I made from aluminium to hold the magnet.  The hall effect sensor and the bracket its on. On the collar you can see the M4 screw used to clamp the collar onto the top nut on pulleys.


Just turned around to show the magnet.  Press fit into the collar.  I don't think its going anywhere.  :-)


Looking at the side of the housing and you can see the bracket clamped on to the side grill.
« Last Edit: November 27, 2018, 08:27:52 AM by Joco »
James
Wellington - NZ

Offline bwal

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #21 on: December 14, 2018, 10:32:01 PM »
HI Jo,

Where did you get the parts for the digital tacho? Ebay? That's something I'm interesting in doing on my mill.

Ben.

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #22 on: December 15, 2018, 01:50:44 AM »
Ben - got them off AliExpress.  But I suspect the same thing is available on eBay.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #23 on: December 16, 2018, 07:51:22 AM »
Some progress today on finally getting the new buttons and speed potentiometer (POT) working.  I had been having issues with the external POT not being recognised on powerup.  It all came down to having to use shielded cable.  I was using Cat5 UTP and while this worked fine for the buttons the POT was being problimatic.  I did a test with some 3 core shielded cable and it started working correct from startup. So since I had to have about 6 wires for to one of two VFDs I shifted to Cat 6 STP (actually SFTP) and we have a nice tidy run, fully shielded and working correctly.


The buttons are
Top row from left: Stop, Forward, Reverse, Speed Dial
Bottom row from left: Table feed On/Off toggle, Pump on/off toggle, eStop that kills table and spindle. Once I get the CNC BF20 built I'll engrave the lables on this plate.




The POT is an interesting on I got from Banggood.  Its a 10k ohm multiturn POT with a neat dial that shows the turns and the graduation in a turn.  Want to get to about 50% speed, turn to the outer number is 5.  Then adjust from there to get the rpm that works best.




So after this success and while I happen to have the vice off I decided to do a more accurate tramming of the head from left/right to the table.  I had done this previously on the vice and had to pretty good but felt it could be done better.  So I setup my 0.01mm DTI to trace an approx 430mm diameter circle. Given that size circle this should provide some pretty good sensitivity. So after a few sweeps and some nudging on the spanner we got ourselves to this position:

 

I think over 430mm we can call this good.  To do any better I'm going to need a 0.002mm DTI.

Cheers,
J.
James
Wellington - NZ

Offline Admiral_dk

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #24 on: December 16, 2018, 06:38:32 PM »
Great accuracy - you should be very pleased  :cheers:

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #25 on: December 23, 2018, 07:58:48 AM »
A little more progress today.  The plan to be able to run the horiztonal and vertical spindles off the same VFD is starting to come together with the arrival of this big ass changeover switch.

The two motors are VERY similar with all the VFD parameters being the same plus the change over wont be done without powering off the VFD. Given that moving to horizontal milling is quite an exercise this depowering process shouldn't be an issue.


So taking the eletronics box door off and mounting on the table so as to thin the 6mm aluminum down a little, in the same way as the existing power switch has been seated. Used a HSS 12mm 4-flute end mill running at 1700 rpm.  A bit of WD40 and a robuts feed rate and things were cutting very nicely with nice tight chips.




The resulting switch mounted and the door back in place.  The intention is the left-hand switch will be Master Power and the right hand swicth will be Spindle Drive Selection.  Once I have things a bit more sorted I'll be taking the old signage off and replacing with something else. Ideally carved on a yet to be completed CNC'd BF20.


Cheers,
J.
James
Wellington - NZ

Offline Muzzer

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #26 on: December 24, 2018, 05:53:44 PM »
Hi Joco

Looks very nice! Handy having the horizontal spindle too, particularly as uses the same tooling.

BTW, from my own investigations, it seems that BT30 is only ever used with pull studs, whereas NMTB30 (imperial) / ISO30 (metric) have the extension collar for a drawbar. However, it doesn't really matter which you use on a manual mill if you have a different drawbar length for each - slightly longer for the BT30. On my ISO30 Bridgeport clone I use both. I actually have a pullstud system and simply use longer pullstuds for the BT30 tooling, which is more readily available.

The backlash arrangement that uses 2 nuts may not be the end of the story. If there is any noticeable wear on the leadscrew, it will be worse in the "middle" of travel where it has seen most use. If you minimise backlash there, you will find the leadscrew becomes very tight as you move the table away from that position. This will force the nuts apart and possibly distort or strip the adjustment screws. There's no simple solution apart from tightening the table locks and/or using a DRO to compensate. I've fitted Chinese rolled ballnuts to my X and Y axis and that has reduced the backlash to something like 0.01 - 0.02mm or so.

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #27 on: December 25, 2018, 07:25:22 AM »
Cheers Muzzer.

Backash isnt looking too bad across the entire screw length.  But also have a DRO fitted which helps massively.

On the BT30, yeah have seen a lot of use of it in the CNC space with pull studs.  The confusing part is the horizontal arbor for the mill is also BT30.  So it “looks” like that is the intended taper as the horizontal arbor is orginal to the mill.  However I have a little spacer collar for the drawbar so I can use BT30 and NT30 with ease.  At the moment the draw bar on the BT30 seems to be working pretty well.
James
Wellington - NZ

Offline Muzzer

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #28 on: December 25, 2018, 09:39:31 AM »
BT30 and ISO30 / NMTB30 are pretty much identical apart from the presence or absence of the collar (and a groove for an automatic toolchanger). It seems rather unlikely that your horizontal spindle was intended to take BT30, so if the drawbar is the right length for BT30, it suggests either it is longer than the original drawbar, or is missing a spacer. Does an NMTB30 tool fit too?

Sounds as if your wear is fairly limited - better than mine was!
« Last Edit: December 25, 2018, 09:43:01 AM by Muzzer »

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #29 on: December 25, 2018, 06:33:51 PM »
Muzzer - NT30 and BT30 are the same taper as you noted and other than the “collar” look identical. I have a mix of a BT30 and NT30 holders and all fit nicely other than needing to use the spacer collar on the drawbar to account for the different lengths needed between BT30 and NT30.  For convenience I have been tending to get BT30 holders for new purchases. Just so I dont need add/remove the spacer on the drawbar too much.

My comment re the horizontal arbor is not to do with the drawbar length but that the actual taper on he horizontal arbor looks like BT30 as it is missing the extra collar length at the end of the NT30 holder.

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #30 on: January 11, 2019, 09:26:20 PM »
It's been a bit quiet over the holidays while I waited for some more parts to turn up.  So I mucked about a bit and did the following.

[1]  Changed the buttons a litte on the control panel.  I wanted a more overt STOP look to the red button and a different colour between the table power feed and coolant. Here's the result.  Of course I still need to sort out the labeling.  I also got the wiring for the eStop fully sorted out.  So that now it prevents the spindle and table power feed from running when triggerered.



[2] Made a "speed handle" for the mill vice.  Been wanting to do one of these for a while and I had made the hex holed part a while ago, just never gotten my "a" into "g" to finish it until now.  The tappered handle is 6061 ali and it feels really nice to hold.  The rest is all mild steel.




The fit on the vice hex is excellent.  A nice sliding fit, not tight and not sloppy. The handle spins freely but is not sloppy on the retaining "screw".


I might polish up the main parts edges but at the end of the day this is a functional tool that is going to get a bit dinged. So I'm not too fussed about going OTT on the finish.  I did have fun practicing draw filing on the front and back face to get a really nice smooth finish. That was more for learning than anything else.

Anyway, a nice and useful addition to the tools supporting the new mill.

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Dah Lih DL-VHR-GIF mill - a journey of discovery
« Reply #31 on: January 12, 2019, 07:54:47 PM »
Here are the drawings for the speed handle for anyone interested.  You will see from the drawings that I did the handle differently (i.e. only tapered for 25mm not the whole length).  This was so I could more easily mount the part in the collet chuck after cutting it from the stock bar.

Note this design is not mine or unique.  There are a number of people on the net who have done similar things and these types of handles are available commercially.

Cheers,
J.
James
Wellington - NZ