[pippin88]

Peter,

Great to see progress.

Interestingly my mill has the Z gib on the right, on the hand wheel side, opposite where yours is.
Our mills must be different revisions.

[Fastest1]

Pippin, Has Peter done the Z carriage flip as Hoss did? This mod gives more Z clearance by flipping the carriage over. That would explain why the Gib is on the opposite side.

Just a thought.

[phomann]

Hi,

No I haven't reversed the head. The TM20VL has ample Z-Axis clearance as the Z-Nut attaches to the lower end of the Head. If you look at the images in post #26 you can see the clearance.

In fact I need to get the slot in the column lengthened fo I can lower the head a bit more.

Cheers,

Peter

[pippin88]

My Z carriage actually has mounting points above and below the boss where the head mounts.

I believe my mill was from the first batch of long table variants, and there are a few things that make me suspect it's a bit of a prototype.

[phomann]

Well, the Z-Axis brackets are finally done. That's the last of the axis conversions.

The drive is a 1:1 belt drive. I chose the pulleys and belt from what I had on hand to match the stepper /ballscrew centre distance. All the drives are set up as 1:1 but I'm using 3 different pulley sizes.

Still so much work to be done. I think I'll jury rig up the motors and give it a run to see how it goes.

A couple of photos are attached.

Cheers,

Peter

[phomann]

Hi All,

I finally got around to wiring up the motors on the mill.

I'm using my 570 oz.in 5A stepper motors on the mill. The pulleys are set up for a 1:1 ratio.

I have a G540 based controller for my Taig milling machine and it was always one of my goals with this conversion was to determine how well a machine of this size would run of a G540 controller that is limited to 48V and 3.5A/ph. This was also part of the reason that I used a pulley drive setup so that I could try different ratios if need be.It must be said that the main reason for the pulleys is to tuck the motors out of the way which has worked out very well.

I set the current for the motors at the maximum 3.5A and started to tune them up in Mach3, not sure what could be achieved. To my surprise I was getting 6 meters a minute (236in/min) out of the X and Y axis. I left the Z at 4meters/min. That seemed like more than enough speed for rapids on a machine this size.

I then wrote a small G-Code file to rapid the X and Y to the extent of their travel. I'm getting 470mm travel out of the X axis and 190mm out of the Y.

A short video of the machine running this program is here;

http://youtu.be/caZ6F5MT8FA

I then loaded the road runner program as it is a good test to check for motor stalling and it ran fine, albeit a lot of rocking and shaking. I put the head on table to add some extra weight. The video is here;

http://youtu.be/AjfhQUBjBjI

I'll end up reducing the rapids to no more than 5m/min (200in/min). I still have to test the Z-axis but I'm sure that it will be fine running of the G540.


If anyone is considering converting one of these machines, a G0704, BF20 or similar sized machine I's suggest you seriously look at the Gecko G540 as an option. I don't believe that a larger driver will provide better or useable performance.

At this stage I'm not going to bother about looking at larger stepper drives for this machine. I could try using the 387 oz.in motors but they only have a 1/4" shaft and my pulleys have a bore of 3/8"

Cheers,

Peter

[phomann]

Hi all,

I need some advice. I'm working on the head and have removed the Z-axis manual movement arms along with the fine Z adjustment as the spindle will be fixed in the head.

The spindle has a rubber washer to protect it from banging into the head when the spindle is fully raised. Presumably I remove this rubber washer and discard it?

Also what is the best way to fix the spindle so it does not move in the head. (apart from rotating)

Cheers,

Peter

[SCzEngrgGroup]

Peter,

Can't you leave the existing quill lock to keep the quill in place? For that matter, if you're moving the head why bother removing the quill feed? Just leave it there, and lock the quill.

Regards,
Ray L.

[hoss2006]

Hi all,

I need some advice. I'm working on the head and have removed the Z-axis manual movement arms along with the fine Z adjustment as the spindle will be fixed in the head.

The spindle has a rubber washer to protect it from banging into the head when the spindle is fully raised. Presumably I remove this rubber washer and discard it?

Also what is the best way to fix the spindle so it does not move in the head. (apart from rotating)

Cheers,

Peter

On my g0704 I removed the rubber ring so it made solid contact and replaced the quill lock lever with a long setscrew to lock it in place.
I also removed the quill handle and fine feed gearing, don't need it anymore with cnc so it saves weight and has less clutter now.
Hoss

[phomann]

Hi Ray, Hoss,

Thanks for the replies. To be honest I pulled everything off the head that wasn't needed about a month ago. I'll have to look back through the box of bits.

From memory, the quill lock was a knob in the centre of the quill feed handle. I'll have a look and see what I can find.

As to the rubber ring, I'll ditch it.

BTW, getting the fine feed shaft was a pain. en the end I drilled out what I belief was a grub screw.

Cheers,

Peter

[pippin88]

Peter,

The quill lock should be on the left side of the head just near the bottom of the control box (at least it is on mine)

The knob in the centre of the quill feed engaged or disengaged the fine feed from memory.

My fine feed kept falling out of it's own as the grub screw fell out.

[phomann]

Hi,

Thanks for that, I found the 8mm threaded hole. I'll put a grubscrew in it.

Cheers,

Peter

[phomann]

My next problem is to remove the bronze pinion off the motor shaft. It has a key in it.

I tried to fit a gear puller but there isn't enough space to to fit the puller claws under the gear. The star that the claws attach to is too wide. It is as if the pinion diameter is too small.

Is it just a matter of getting the proper sized gear puller?

Cheers,

Peter

[phomann]

Hi Guys,

I managed to jury rig a puller and get the pinion off so al is good.

Cheers,

Peter

[pippin88]

Peter,

I'm very interested in the rpm range of the motor, are you able to measure it? (I'm planning a belt drive and would like to get 6-8k spindle rpm and need to work out my pulleys)

I got my mill going, cut it's first part (Z axis ballnut mount, a replacement for a 3D printed ABS part I used).

Cheers,
Nick

[phomann]

Hi Nick,

My spindle motor is not running at the moment as I'm in the middle of converting it to a belt drive.

I'm using the kit from Scott at Bench Top Precision Main

The kits are beautifully made. They are almost too good to put on a Chinese mill. In fact I'm so impressed with the quality I'm going to stock them, along with a few of Scott's other offerings. The kit just bolted cleanly onto the head and motor. It also comes with a belt cover for the front of the mill.


I've just ordered some new bearings, a Set for the spindle and another for the intermediate shaft(not sure what to call it) I've figured that since I've completely dismantled the head I might as well replace the bearings.

Below are a few pics of the Bench Top Precision belt kit.

Cheers,

Peter

[Aaron Powter]

Hey Peter, that belt drive conversion kit looks very nice. Very jealous now ;-)

[phomann]

Thanks Aaron,

I'm looking forward to getting it installed. I'm struggling to get the bearings off the older counter shaft. The smaller one came off with a puller. The larger one is more difficult as I can't getter the puller under the bearing as the gear is in the way.

In the end I've got some new bearings on the way.

Cheers,

Peter

[phomann]

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[phomann]

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