18" x travel mill for CNC conversion

[Daox]

Hello, new guy here. I posted in a different thread, but got no response. I also figured I'd add a bit more to my first post, so I started a new one. I'm starting to look for a mill for myself. I do a lot of custom car work and enjoy fabrication and maching (although machining is quite limited atm). I worked for a few years as a drafter in a machine shop and did some after hours maching on their bridgeport knee mill, engine lathe, and learned some M and G coding. So, I know a bit, but not a ton about the machines themselves. Most of what I know is focused on production work as it was a job shop.

So, I'm looking for a mill with about 18" or more of X travel, probably around 6" (or more) of Y, and 6" or more in Z. I want to be able to machine flanges for engines so the X travel is quite important. However, to top that all off I definitly want to upgrade the mill to CNC in the relatively near future. In doing custom work I end up developing things that other people also like and I want to be able to reproduce those parts quickly. The materials being used will vary widely from steel to alunimum to one of the things I currently make which is a phenolic insulator. I make them by hand currently, see attached picture.

The Vario BF20 looked like it fit the bill but I see in a recent thread the morse taper tooling holders are hard to find. The Grizzly G0619 doesn't seem to be a bad alternative, or even the G0463 even though they both only have 15.75" of X travel. Again, I really want to convert to CNC. Have these been done before? I guess I don't have many reservations on designing my own CNC conversion, but if there is an easier option I'm all ears.

On the CNC conversion I have looked around a bit and see that you basically need stepper motors, a controller, power supply, and a computer (and software) to run the system. Is this mostly correct? As far as the stepper motors go, should I be looking for any specific torque output to handle steel cutting? I guess I should ask the same for the mill's spindle motor too.

[ataxy]

morse tooling is not that hard to find and yes the bf20L and not the bf20 would fit the bill also for the setup i would encourage you to add limit switch to your axis for steel i would try to go at least 1hp but it also depends on what type of steel and the tool you intend on using to cut that steel

[Daox]

Thanks for the Input ataxy. Could you provide a link to a source(s) for morse tooling?

I must say I do like the idea of the additional horsepower and travel of the Vario mill. The price is also quite similar to the lesser Grizzly mill (this is the X3 I see talked about, right?). Can anyone mention on the difference in quality between the two mills though? I see a lot of mention of tearing down mills once people get them to scrape ways, etc. As I'm sure most would, I don't really want to have to do this if avoidable. As far as steel goes I can't ever see doing any exotic alloys. Most everything will probably be mild steel or on occasion stainless. As far as tooling goes I would probably be using mostly HSS or tungsten endmills unless anyone has better ideas. Indexable tooling is great too, but expensive. I would definitly think about a indexable face mill though. I'll be searching soon, but has anyone converted the Vario BF20L or regular BF20 to CNC? Input here would be great. FYI, I do not have a lathe on hand to do any turning, so all maching for the conversion would need to be done on the mill, or sent out.

[ataxy]

well most mt2 tooling i got it from ebay and so far i had no problem with it and the quality of it was on par with the mill
as for tearing down mine did not need any as all ways are grounded are are as flat as it can be
as for tooling i highly recommend you get carbide endmill they make a huge difference in the precision of the cut and in the long run the amount of material you will be able to cut without it needing resharpning, anyway its my opinion and mostly if you intend on doing steel and stainless
as for conversion here is a wonderfull conversion that turn out at the end to be a full conversion as the mill cannot even be called a vario anymore but its still interresting
Heavily CNC converted Opti BF 20 Vario
and some other
BF-20 CNC Conversion

[Daox]

Thank you very much for the help and the links. I'll definitly read through them shortly. I did see the one on the heavily modified mill, but didn't read through it much.

As far as machining steel goes, say I want to spin a hole in a piece of 1/4" thick mild steel plate. Lets assume I'm using a carbide 1/4" endmill and spinning a 2" hole. What kind of depth of cut can I take with this machine? This would probably be a good example of something I would do with the machine fairly often.

I also checked ebay real quick and found this 2mt collet holder and collet set. This would be what I would need, right?

http://cgi.ebay.com/1-8-5-8-ER-TYPE-...QQcmdZViewItem


Or, would this be the better choice?

http://cgi.ebay.com/MORSE-TAPER-COLL...QQcmdZViewItem


I realize both would work, but is there any advantage to either of them (besides price)?

[ataxy]

with a 1/4" i am pretty sure you would be able to go .100/.125, hell i did a simple heatsink the other day with a 1/16"x4flutes carbide endmill and i was able to give it .100" per pass with a pretty slow hand feed and plenty of water soluble coolant, thats the thing with carbide endmill they are stiff and do not flex under pressure you just have to find the sweet spot and they cut like a hot knife true butter, i have also notice that they tend to pack less in aluminium then hss

go with the er-25 collet

[gerryv]

Anyone know if there a North American source for the Vario BF20L and if not, are their machines available with single phase 60 Hz? Thanks, Gerry

[ataxy]

i am not sure but penntool can get it but they dont carry it as standard stock you would then get a bf200l wich is exactly the same but rebrand

[Daox]

I just emailed penn tool and asked if they could get the BF20L. I'll let you know when I get a response.

Has anyone used the Optimum CNC conversion kit for the BF20/L? I see they have one on their site. It looks like it comes with all the mounting hardware, stepper motors, and belts/pulleys to convert for $815 US (you still need a controller). They also offer ballscrew conversion for around $350 per axis.

http://www.optimum-machines.com/prod.../61/index.html

[Daox]

Alright, I've been reading more on the forum about the limitation of the 2mt spindle. Why is this a severe limitation? 5/8" is the largest tool you can fit in it, right? So, what would you like to use that is larger?

[ataxy]

well see its true that you wont be ablt to go higher then 5/8", but you can find some er-32 collet for mt2 taper on ebay, but tooling over 5/8 for such a small machine i think is overkill anyway for the component, the only true con in my point of view is that you mt2 holder wont be usable in the event that you plan on upgrading eventualy tu a bigger mill like a rong-fu 45 type of machine or a even bigger bridgeport type kneemill but aside from that mt2 collet work perfect on the type of machine

[Daox]

As far as the CNC conversion goes, do you think I can I get away with a Xylotex setup? I don't really know the relationship between torque and speed output of the stepper motors except for the fact that people say you loose torque as you speed them up. Is there any good source for stepper motor info somewhere? Other than the Xylotex setup, theres the Gecko drives and what else?

It also seems mach3 is the software to have. I take it that this software works with pretty much everything?