Dah Lih DL-VHR-GIF mill - a journey of discovery

[joco-nz]

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 the nice 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.

 

[DJP]

I made a similar upgrade to a Bridgeport from an horizontal mill that had a vertical attachment. I only used the horizontal feature once on the old mill and the Bridgeport came with a single phase motor replacement. My suggestion would be to install and single phase motor (may need a mounting plate) to the 'J' head portion of your new mill and disconnect the other motors. 90% of your requirements will be covered and you can be operational quickly and at low cost.

A suggestion for your consideration.

 

[joco-nz]

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.

 

[joco-nz]

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.

 

[joco-nz]

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.

 

[Cogsy]

For a way cover on my mill I bought a roll of dampcourse material from Bunnings. It's a reinforced plastic stuff about 30cm wide and very flexible. Has been on for a couple of years and still looks like new. 1 roll was about $20 and would give me at least enough for 50 mills...

 

[nel2lar]

James
I would check with an electrician to see if it all could be run on a single VFD or maybe go with a Rotary Phase Converter. 3 VFD's would be quite expensive and all you really need is to create 3 phase power. Check your options before committing.
Nelson

 

[joco-nz]

Nelson - good points. The VFDs are relatively cheap and massively cheaper than a RPC. At the moment I have 4 motors on the machine. So it’s looking like ...
1. Coolant pump motor: Dual voltage 1/8HP. Use a static converter to run at 230V

2. X axis power feed motor: Dual voltage 1/2HP. Use a static converter to run at 230V

3. Horizontal spindle motor: 400V only, 1 HP, 4 pole. Use VFD capable of supplying ~400V

4. Vertical spindle motor: 400V only, 4 pole and 8 pole, 1 HP. Use VFD capable of supplying ~400V linked to only 1 pole set.

Anyway no heavy commitment in any direction yet that can’t be easily recovered and I’m still planning the electronics.

Cheers,
J.

 

[nel2lar]

James
I might be wrong but the way I am looking at it and at any one time you would be drawing less than 2 HP. What about the idea of running a single 2 hp 220 single to 3 phase then draw everything off of it.
Nelson

 

[joco-nz]

Nelson - the challenge I have is two motors are not dual voltage. So I need to either feed them 400V, get them rewound or replace them with dual voltage motors.

At the moment the VFDs I have sourced (total outlay about $300 NZD) claim to be able to output 400V (or 380V which should be close enough). So if they do what they claim I’m golden. If not I’ll sell them and look at next options.

Cheers,
J.

 

[bruedney]

Nelson - Any reading you do on VFDs states that there should be no switching between VFD and Motor therefore running mulple motors off one vfd is likely to fry the vfd.

 

[Racene]

Whenever I come across discusions on VFD and their associated costs I wonder why no one has explored the DC option,there's heaps of DC treadmill motors from 1.5HP -4.0 HP out there,enough power to rip your bloody arms of as" Aunty Jack" would say, a very easy conversion with full speed control,check out You Tube on treadmill motors.I've converted my pedestal drill using a 1.5 HP DC motor,geared 2:1 works fantastically,next project my Lathe with a 2.0HP DC motor

 

[peter2uat]

I would not expect you driving the vertical AND the horizontal spindle at the same time - right? so ONE VFD IS enough, but dimension it to carry a load of around 2.5 - 3KW - taking into account the power surge you have when starting a motor. You will have to clamp both spindle motors to the same points on the VFD. No switch needed between them. And the X axis motor as well as the coolant pump may run on their converters as they did before. No need for any further VFDs.
Greetings form the exact other side of the world!

 

[joco-nz]

I would not expect you driving the vertical AND the horizontal spindle at the same time - right? so ONE VFD IS enough, but dimension it to carry a load of around 2.5 - 3KW - taking into account the power surge you have when starting a motor. You will have to clamp both spindle motors to the same points on the VFD. No switch needed between them. And the X axis motor as well as the coolant pump may run on their converters as they did before. No need for any further VFDs.
Greetings form the exact other side of the world!

Greetings!
From your description you are suggesting that when the vertical spindle is running the horizontal is also running as the single VFD runs them synchronously, as happens in multi motor conveyor systems under similar frequency control aystems? The cocnept being load (resistance due to cutting) is only ever on one motor at a time.
Yes that would texhnically work. Noiser than things need to be as you would always be driving the horizontal spindle gear box. But as I noted the cost of the VFD is pretty small in comparison to the mill of so two is not a big deal.

I can see that one of the VFDs on order is in Auckland so should be in my hands in the next few days. Then i have a manual and unit to look at and will know if I’m keeping it or starting to look at alterntive means to deal with powering this thing.

Cheers,
J.

 

[Anatol]

, rip your bloody arms of as" Aunty Jack" would say,

And she will too! LOL!!!
Now there's an obscure reference totally lost an anyone not of a particular australian generation.
For those not lucky enough to be in-the-know, here she is in all her glory,
an early antipodean exponent for the LGBT community

 

[Anatol]

Whenever I come across discusions on VFD and their associated costs I wonder why no one has explored the DC option,there's heaps of DC treadmill motors from 1.5HP -4.0 HP out there,enough power to rip your bloody arms of as" Aunty Jack" would say, a very easy conversion with full speed control,check out You Tube on treadmill motors.I've converted my pedestal drill using a 1.5 HP DC motor,geared 2:1 works fantastically,next project my Lathe with a 2.0HP DC motor

seriously though, I agree.
Power mosfet * technology is just extraordinary now, and DC motors are more efficient, more powerful and more abundant - thanks largely to powerful and cheap Chinese magnets, and the electric car market.
*how I hate spellcheck, I just noticed that mosfet had been change to misfit

 

[joco-nz]

If the 3 phase AC path on the existing motors fails then I’ll definitely look at DC as an option.

Thanks for the good idea.

Cheers,
J.

 

[peter2uat]

Greetings!
From your description you are suggesting that when the vertical spindle is running the horizontal is also running as the single VFD runs them synchronously, as happens in multi motor conveyor systems under similar frequency control aystems?

No, just not knowing the actual layout of your mill I was of the opinion that the spindles could be switched on seperately, as there would be no sense in running them together

 

[joco-nz]

Ah. Ok. Yes you can’t use them both together. Physically not possible even if you can run them at the same time.

I would be interested in an example circuit taking from a working system running dual drives at different times under VFD control. Not saying it’s not doable, just that there is lots of informtation suggesting strongly its “bad” to disconnect without power off. Now granted the language could be poor and all they mean is you can’t switch stuff while the VFD is trying to drive the motor and if it’s in the stopped state then it’s ok to flick the the connections from one motor to another?

Experienced views welcome.

Cheers,
J.

 

[bruedney]

Given you "program" the VFD with the data about your motor I don't think it would be wise to try to run 2 different types and sizes of motor from the same VFD