[bbatarelo]

Hi there,

I've been looking into buying a milling machine for quite a while and Optimum has this rather new thing called MH25SV. Though it is 60 kilos lighter then BF30, it has all kinds of interesting things such as motorized x/y axis, DRO. However, nothing indicates in Optimum catalog if this machine can be CNC retrofitted which is something I'd strive for eventually. On the other hand, BF30 is a pretty well known device.
When it comes to pricing, it's almost identical so I'm left with dilemma:

BF30
- well known
- 60 kilos heavier
- overall good machine

MH25SV
- new
- comes with motors/dro which tend to be costly items in CNC upgrade process.

Again, that's where BF30 is good because of it's popularity, and I don't know to which extent electro-mechianical components on MH are something I'd want to use as a basis for conversion.
So, MH25SV looks to me as overall good machine
- if it has enough rigidity
- if it can be retrofitted to CNC

Also, I'm not afraid of doing the manual CNC upgrade as long as it's not extremely cumbersome process. I am capable of building electronics and programming it and in machining I'm newbie with D210-400 lathe and hundreds of hours of videos by Tubal Cain and others.

I'd hate to look back after spending a lot of money crying for more robust machine. I'd also hate to go MH route and figure out that I need to re implement everything that gives it current electromechanical properties (by either purchasing or making new). However, if CNC upgrade means motorizing Z axis and we're more or less good to go, then it might be an interesting machine to begin with.
Anyway, maybe I'm just talking a bunch of nonsense in which case I apologize

Thanks,
Bruno

[lcvette]

I think at best you wouldn't need to make a few mounts bit still likely modify a few things to fit. Motor mounts in my opinion are about the easiest part of a conversion. The tougher parts are modifications to the mill castings fo ballnut mount placement because you are usually left without a machine to do these and have to take it somewhere and have then do it or use hand tools which is kind of crude on a Precision machine.

In the end, on machines this size it generally books down to mass. Given the same choice between the two machines I would definitely go for the BF30 and its beefier base frame. In the short term. The powers axis' and dro would be nice while manual bit pointless once cnc'd

My guess is the motors aren't steppers and you would still need drives for them for CNC so there would be no cost savings there most likely. The dro wouldn't be terribly important once cnc'd because you only really need to measure axis movements during setup and once they are correct they pretty much remain the same unless you change something to effect them. And once cnc'd, the machine or Linux screen dros would be more then accurate for parts you would plan on making with this size machine.

That said I have no experience with the new machine you listed so my recommendation is solely based on ideas of what may be.

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[bbatarelo]

Hey Icvette - thanks for your insight, makes sense. I made some more research through Optimum catalog and here's couple of information which I find intriguing:

aside from the fact that MH25SV sits between BF20 and BF30 models, it actually has all 3 axes covered by motors. Also, there's a CNC retrofit kit for BF20 and 30, but not for MH. Then again they don't mention any ballscrews, or steppers, but they do mention servos. So yes, you are probably right

[LongRat]

With the smaller machine you are just paying for motors and DROs which you will effectively be throwing away. The bigger rig is a no-brainer.

[Tkamsker]

hi croatia is not far from austria we build cnc machines similar to bf30 they have vfd iso 30 linar rails ballbearing spindles and you can choose the drive if steppers closed loop or servo so if you like finnished product drop us a note if you like the cnc retrofit on your own it s ok as well thomas


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[bbatarelo]

Yes, everything seems to be going in that direction. Anyway, LongRat - I've quickly scanned your posts and I figured out that you might be the perfect person to ask the following.
In case I decided to go the BF30 round, I probably won't have time and instant funds to do the full conversion and to be honest, I'd like to gain some experience in milling the traditional style. Do you think it's possible to do gradual upgrades without upsetting the basic mill functionality? By that I basically am referring to doing lead screw swaps. Is it possible/advisable to make lead screw swap to preloaded ballscrew without affecting handwheel scale AND of course, installing lead screws that have adequate qualities for being driven by motors at later?
Maybe I'm asking a completely stupid question, but maybe ballscrews have different diameters, threads per cm/in or something else for a particular reason I'm not aware of.
Or maybe I simply have to go with some DRO solution and at least cheap digital scales together with leadscrew swap?

Thanks,
Bruno

[bbatarelo]

Hello "almost neighbor" It seems that Austrians are walking around me these days. Yesterday I met two on the same flight to USA I was on. Where can I see your machines?

Bruno

[Tkamsker]

in person needs a trip to vienna at the internet Thojomech smart cnc leistbare cnc maschinen ,..and yes austrians travel a lot -


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[LongRat]

Once you go to ballscrews you can't use handwheels. Any ballscrew you would use on this machine will have a larger pitch than the factory lead screws, so the handwheel scales won't be right. Plus, leadscrews can't be backdriven by cutting forces, but ballscrews can. Tricky to deal with when you are machining manually.
Plenty of people have converted to CNC with stock leadscrews, and upgraded to ballscrews later. If you just need time with a manual machine to get up to speed, leave it totally unmodified and just use it as intended. You don't need DROs to do good machining. Just makes it easier.
If I were you, I would leave the machine standard and use it as a manual, then upgrade to ballscrews and CNC in a single hit when you are ready. You can use the manual time to make as many of the conversion parts as you need. That's how I converted my first machine (a Sieg X2).

[bbatarelo]

That's exactly type of answer and information I was hoping for!
Thank you so much,
Bruno

[Tkamsker]

i think longrat is right normal the handwheel scale doesnt fit cnc scale because you want to achieve a certain speed but you can do your scale as well so it fitts the balbearing spindle i tjink there are 2 "schools" one says if you cnc no need of handwheels ( use pendant ) 2 nd is keep the wheels because even if you have a cnc machine ( hobby size ) you might want to be able to do a fast manual cut
so if you do your konversion it is a journey where you can and will learn a lot just my 5 cebts


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