Never having owned a mill, I recently took advantage of an opportunity to purchase 5 mills with 2 axis Crusader II contollers. 4 of the mills are Lagun FTV-1 units along with 1 Supermax YCM-16VS. I'm told that the controllers do not work, which did not deter me as I intended to perform a conversion regardless. To that end, I'm looking for a bit of advice on the best way to proceed with the conversions. I intend to upgrade 2-3 of the machines with new servos after they are scraped and the tables are ground. I'd also like to have more spindle speed as most of my projects involve aluminum.

Questions:

- What size of servo is recommended for each axis on mills of this size?
- Do solid designs exist for the quill Z axis conversion? To date I've only been able to find information on the Elrod kit but I'd prefer a somewhat DIY approach.
- What's the best way to approach the spindle speed increase requirement? I'd like to be north of 6000RPM if it's feasible.

I intend to open source the designs of any components developed during this conversion process for others to benefit from.

Any advice the members here are willing to share will be greatly appreciated.






I also picked up a really nice Mighty Comet in a separate transaction with a 10x50 table that I'll probably keep manual for the time being.

Nice looking mills you have

Questions:

- What size of servo is recommended for each axis on mills of this size?

Best is to look at the ones fitted already as that will give you a size, in fact I wold use them unless there is a problem with them. On my Beaver NC5 I have 1.5HP AC servos on Z and X and 2HP on Y.

- Do solid designs exist for the quill Z axis conversion? To date I've only been able to find information on the Elrod kit but I'd prefer a somewhat DIY approach.

I made one up for the manual conversion I did but afraid I dont have the drawings any more but heres a pic of what it looked like.

- What's the best way to approach the spindle speed increase requirement? I'd like to be north of 6000RPM if it's feasible.

Would check to see if the bearings are rated for that speed, they should be fine but try and check anyway. A VFD would allow you to over speed the motor and should be fine with the motors fitted but check temps of the motors when running to make sure the dont get too hot. The other way would be to change the gearing if possible, if doing mostly Alu then you could afford to gear up as you would not be needing as much torque as you would if cutting steel or stainless.

Thank you for the reply. I went out on a limb and made the assumption that I'd probably need to upgrade servos given the vintage of the machines. I believe the Supermax is a 1991, but I am unsure of the Lagun's. I hope to pick the machines up this weekend, as they're about an hour away and given the tonnage I'll have to make multiple trips. Once I examine the servos I'll be sure to post up the information about them along with some independent research to see if they'll be suitable for ongoing use.

I also need to verify that proper ball screws were installed when the CNC conversions were performed. I hope this is the case and I find that the screws are in good condition. At least 2 of the machines have excessive noise coming from the heads, so I'm also counting on bearing upgrades for some if not all of the machines. I believe the Lagun's have 2HP motors and the Supermax is at 3HP. Addition of a VFD is definitely part of the plan which I neglected to mention initially.

Since my initial post, I've been contemplating whether placing a CNC controlled servo on the knee is necessary. I've read varying opinions on this matter but my initial thought is moving this type of mass excessively could cause abnormal wear.

In closing, which controller did you end up with? If your build has been posted, I'll make a point of reading up on the work you performed.

There is a good chance the motors are ok, the ones on my Beaver NC5 were perfect and its mid 80's vintage, the ones on my lathe were like new, its also mid 80's but it had done very little work so that was to be expected.
I replaced the motors on both, lathe because I didnt get the drives with it and mill because the drives whistled and it drove me daft. I picked up AC Servos and drives for them.

It looks like professional type conversions so I think they will almost certainly have ballscrews.

I use AC servos for spindles on my machines, I just keep my eyes open and pick them up when I see them at good prices.

Knee or quill is a difficult one, I personally wouldnt think there would be problems with wear, after all its just another axis like the others, either dovetail or box way, keep it lubed and should be fine.
Problem with the knee though is the weight, either a big servo or some form of assistance i needed, often people use gas shocks. Bridgeport and a few others used air assist. I will at some point servo the knee on my Beaver NC5 but it will only be used for tool length offsets and the quill will likely still be used for day to day machining. I would prefer a bedmill though so if one comes along at the right price I may never do the knee conversion.

I use the SmoothStepper on all my machines although the Bridgeport Rigid Ram is getting redone at the moment and I will be using a different controller on it but afraid I cant say too much about it at the moment.

Heres links to the threads on my lathe, beaver nc5 and bridgeport

http://www.machsupport.com/forum/index.php/topic,1234.0.html

http://www.machsupport.com/forum/index.php/topic,10331.0.html

http://www.machsupport.com/forum/index.php/topic,17580.0.html

Don't know what you consider as FAST so

As Hood Mentioned Check the Spindle bearings are rated for higher RPM. If not then they will HEAT up and among many other things cause the spindle to GROW.

Also check the Balls Screw Speed ratings they do have a max Glimit before they start to distort or the bearings SLIDE instead of roll causing premature ball screw wear.

Just a thought, (;-)

I'm sure those machines all have 3-phase spindle motors.  If so, then the answer to your spindle speed question is just a matter of putting them on a good VFD (Variable Frequency Drive).  This will generally allow you to double the max spindle speed by over-speeding the motor.

If your existing servo motors are working, there's no reason you can't continue to use them.  All necessary conversion parts needed to use the existing (I assume analog) drives and resolvers are readily available from pico-systems.com, and others.

On the quill drive - those heads look quite different from a standard BP head, which is what most quill drive conversions are designed for.  Designing a quill drive is a fairly straight-forward undertaking, the only really hard decision being how to attach it to the head.  Some use the four tramming bolts, others, like the Elrod, attach to the lower flange (where the lower end of quill feed-stop screw attaches), and to one or more of the covers near the top of the head.  On mine, I went with an approach I've yet to see anyone else use - I slipped a 1/2" plate between the head and the belt drive housing.  This was very simple, very solid, and required no modification whatsoever to the machine.  (see pictures below, with covers removed).  The other trick is making a rigid enough connection to the quill itself.  This is always done by attaching a yoke to the bolt that attaches the "eye bolt" for the quill stop.  The design of that yoke is tricky.

Regards,
Ray L.

Hood THAT was an excellant design.

(;-) TP

BR549/HimyKabibble

Thank you for your replies. I definitely intend to go the VFD route and given that some of the spindles have exhibited noise, if a bearing replacement is in order I'll make sure the replacements are rated for greater speeds.

Regarding the quill design, Lagun produces a factory conversion based on their FTV-2 model which has a Z axis design which I hope to find more detailed images of. Given the choice, I would follow your lead and try to make as few modifications to the machine as possible.

Thanks to some of the designs posted and a review of the Elrod product, I have a much better understanding of how to approach the matter.

As if I didn't have enough on my plate, as of this afternoon I am the proud owner of a Bostomatic BD32TSG VMC. I may move the retrofit of this machine to the front of the list. Below is a video of a similar unit.

<a href="http://www.youtube.com/watch?v=hqnj3NPvVh0" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/watch?v=hqnj3NPvVh0</a>

It will be a week or so before it arrives, I'll be sure to post pictures.

It appears that I botched the video embed and missed my window of opportunity to edit the post. Below is the video I intended to post.

http://www.youtube.com/watch?v=hqnj3NPvVh0