[eisman]

I am just starting out with CNC as a hobby. I plan to buy a mill and convert it to CNC myself. As I have been searching craigslist and ebay I see a lot of full size mills for sale in the same price range as new mini mills. What are the dangers of buying a full sized mill vs a mini mill for a conversion?

I am doing this on the tightest budget I can. Since it is a hobby I can't justify putting out $5000 just to get started. I am already in the processes of making a desktop mill for PCB milling, still in the gathering stage. I have been doing lots of research here as well as instructables, cncinformation, reprap...
I am pretty sure I want to cut up to aluminum and not much past.

What's your advice?

Thanks
eisman

[mwood3]

Welcome to our hobby!!!

I recommend one of the BF20's myself... IMO they are a step above the X3 and the fit and finish is great. I think i will have well under $2000 in mine after the cnc conversion...

check out one of Hoss's site @ g0704.com

or if you want to go with an X2 he is also the authority on that machine as well, Hossmachine Homepage

if you think you need something bigger than the G0704 then check out Hoss RF45 clone, he has a link on the hoss machine homepage for it. But honestly unless you do really big parts the G0704 can tackle a lot.

[cornbinder23]

I have personally seen both BF20 and X3/SX3 and I dont necessarily think the
BF20 is a "step" above the X3 it might have a tiny bit more travels but as far as fit and finish all of the issues people had with the X3/SX3 have been the exact same issues that are surfacing now with the BF 20. We X3/SX3 owners just did not have to wait a year after purchasing our mills. Looks to me they are both capable little chinese mills, I am not slamming the BF20 just seems to be the "flavor of the month" but it looks like most wont get a chance to sample until next year. I live about 20 minutes from grizzly's showroom so yes I have seen them side by side but I had mine the same day, where as most BF20 "purchasers" wont see theirs until next year. My conversion will be complete by then, in fact its almost complete now http://www.cnczone.com/forums/bencht..._ready_go.html
My 2C is do your research on the mini mills you will see the same issues with all of them, not that those things are deal breakers just little nuances that will have you becoming more familiar with your piece of equipment

Now, sorry for the rant back to your question it all boils down to cost for the conversion, ballscrews, servos, drivers, power supplies etc.. will all be more expensive for the larger equipment, there is a lot of great larger equipment out there but If you cant see it in person you are taking the same chance as anyone buying something sight unseen

JTCUSTOMS

[hoss2006]

I think I'll clarify a few things.
The G0704 is new to us and just as when the X3 came out, it will take a while before inventories catch up to demand.
There is a LOT of demand and trust me, it's NOT "just a flavor of the month".
There is a reason that companies are dropping the X3 from inventories and that the ones that still
carry them, have plenty in stock.
One of the issues with the X3 is the Z axis and it seems to be for ALL X3's, read one of the threads here.
http://www.cnczone.com/forums/bencht...ase_chime.html
G0704 have had a couple of issues too as with any mill but seems to be only a small percentage.
The main difference between the 2 mills is performance.
I've tested my g0704 and other owners have reported as well, the g0704 IS much more capable.
I've seen lots of X3's posted over the years and no one has posted video of one cutting
as well as the g0704 can, especially in steel.
That's why I choose it over the X3 and was willing to wait for one to come in.
Good things come to those who wait.
I predicted back in Jan. that the g0704 would become very popular and it has and then some.
As more time goes by, there will be plenty of conversion kits and accessories available for it,
and inventories will catch up to demand.
I would imagine you'll see even more suppliers surface over the next several months.
This flavor is here to stay.
Hoss

[cornbinder23]

The OP wanted a very simple question answered I was not advising on WHICH mill to get just that there are differences of opinions on these little mills
If you have something to add to the OP original question I am sure he would love to hear from you Hoss as I said before I am not slamming your precious G0704 it IS a good mill, as is the X3 SX3. he also said he was not interested in machining anything past aluminum so as far as the steel machining goes he obviously has very little interest in it, the pissing contest between all of these chinese mills doesnt really belong here, advice on his original question does

I believe I am the only one who has contributed to the question he has asked

JTCUSTOMS

[hoss2006]

The OP wanted a very simple question answered I was not advising on WHICH mill to get just that there are differences of opinions on these little mills
If you have something to add to the OP original question I am sure he would love to hear from you Hoss as I said before I am not slamming your precious G0704 it IS a good mill, as is the X3 SX3. he also said he was not interested in machining anything past aluminum so as far as the steel machining goes he obviously has very little interest in it, the pissing contest between all of these chinese mills doesnt really belong here, advice on his original question does

I believe I am the only one who has contributed to the question he has asked

JTCUSTOMS

Oh man, another chip on someones shoulder.
He's asking for advice on mills and I gave mine.
I'm sorry that the facts upset you but that's your problem,
If you don't want to hear an opposing point of view,
don't go off on rants, as you said,

sorry for the rant

If you just have some personal problem, then you can PM me and we'll discuss it.
Hoss

[rcazwillis]

Does not appear the question of used vs new mini has been addressed. You state a desire to CNC the machine. A used full size mill will be very costly to CNC as it will take bigger parts on everything. If cost is a big consideration and you are new to it, I suggest going with one of the mini mills and start following all the threads on the one you purchase. There is plenty of info on this forum to help you get it CNCed the most economical way. And don't be shy asking for help, the people here love to give direction and advice. Supported by the responses to your question, they enjoy comparing mini's at time too.

I am just starting out with CNC as a hobby. I plan to buy a mill and convert it to CNC myself. As I have been searching craigslist and ebay I see a lot of full size mills for sale in the same price range as new mini mills. What are the dangers of buying a full sized mill vs a mini mill for a conversion?

I am doing this on the tightest budget I can. Since it is a hobby I can't justify putting out $5000 just to get started. I am already in the processes of making a desktop mill for PCB milling, still in the gathering stage. I have been doing lots of research here as well as instructables, cncinformation, reprap...
I am pretty sure I want to cut up to aluminum and not much past.

What's your advice?

Thanks
eisman

[hoss2006]

I am just starting out with CNC as a hobby. I plan to buy a mill and convert it to CNC myself. As I have been searching craigslist and ebay I see a lot of full size mills for sale in the same price range as new mini mills. What are the dangers of buying a full sized mill vs a mini mill for a conversion?

I am doing this on the tightest budget I can. Since it is a hobby I can't justify putting out $5000 just to get started. I am already in the processes of making a desktop mill for PCB milling, still in the gathering stage. I have been doing lots of research here as well as instructables, cncinformation, reprap...
I am pretty sure I want to cut up to aluminum and not much past.

What's your advice?

Thanks
eisman

By full sized mill, are you talking about a kneemill?
From what you seem to wanting to do it's more than overkill, have you seen one in person?
They are BIG, around a ton.
If they are that cheap used, they are going to need some work that won't be cheap
but once done, you could have a mill that would last decades.
The chinese benchtop mills are as cheap new because they are A, smaller and less capable
and B, not built to the same quality.
They are what they are, a way for the average guy to be able to do some machining
without breaking the bank or needing a forklift to move them.
They are capable of holding decent tolerances but as noted above,
may need some user tweaking to correct some of their misgivings.
depending on the model.
Don't forget to check out the taigs or sherlines too, though small, they have good tolerances.
You can get up and running with a CNC benchtop mill for less than $2k, depends on what you can do yourself to get there.
Hoss

[mwood3]

The OP wanted a very simple question answered I was not advising on WHICH mill to get just that there are differences of opinions on these little mills
If you have something to add to the OP original question I am sure he would love to hear from you Hoss as I said before I am not slamming your precious G0704 it IS a good mill, as is the X3 SX3. he also said he was not interested in machining anything past aluminum so as far as the steel machining goes he obviously has very little interest in it, the pissing contest between all of these chinese mills doesnt really belong here, advice on his original question does

I believe I am the only one who has contributed to the question he has asked

JTCUSTOMS

I edited my post to add IMO to the start of it...lol maybe this wont be so provoking to some people. I have veiwed and demoed the X3 also and thought it to be of poor quality for the $1000 price tag...thats why i jumped on the BF 20 after seeing the one hoss ordered, I have to say i couldnt be more pleased with it and other than not having a second mill to help with the cnc mods I couldnt be more pleased.

[mrcodewiz]

I like my G0704, I have made my X2 into a machine that is pretty capable and accurate. I have never used the X3 but both of those statements could probably apply to them as well.

Others have pointed it out but the danger of going with a bigger machine (besides needing potential repairs) is that the larger the machine, the more expensive the conversion to CNC will be.

[eartaker]

eisman,

Let me ask you this since the past few have not....

What are you wanting to make and what size of parts are you looking to make? This answer will let us all know the size of mill you may need whether it be a X2 or a knee mill.

[mwood3]

eisman,

Let me ask you this since the past few have not....

What are you wanting to make and what size of parts are you looking to make? This answer will let us all know the size of mill you may need whether it be a X2 or a knee mill.

A thought just occured to me after reading this....It might be a good thing if someone could put together a sort of sizing guide along with examples of work that is commonly done on each size machine in its stock form...

[eartaker]

mwood3,

That is good, I like that idea. Have it in a table format and somehow convince the moderators to post it up as a sticky. I would say have a pole or something per machine or just a thread with input from all users and have a moderator make the table.

[mwood3]

mwood3,

That is good, I like that idea. Have it in a table format and somehow convince the moderators to post it up as a sticky. I would say have a pole or something per machine or just a thread with input from all users and have a moderator make the table.

It would have to be sort of a community project but we may have to devise a way to keep the "bragging" out of it...I can see some issues with it but i also see how it is do able.

[eartaker]

Of course you would have some users say "Well I can get X" amount of travel if I do this on my X2 or other machine..." I could see it being an issue but it is do able.

[mwood3]

Of course you would have some users say "Well I can get X" amount of travel if I do this on my X2 or other machine..." I could see it being an issue but it is do able.

I think the best approach is to show what size of parts are best suited to each "stock" machine...we should allow some overlap of part sizes between machine but give each one a range. It should be taken into consideration that it is a "normal type setup" and nothing extreme is done to obtain the setup. also I think pictures of the setup may be key here also to give users an idea of how much real estate you can lose with the tooling/workholding solutions.

[diyengineer]

I would really like to convert both my G0704's to CNC but because of my lack of cash i would rather sell one to convert the other G0704 i have. Its brand new never used comes with MT3 spindle (purchased new @ grizzly auction). I was going to convert it over to a R8 spindle for ($125 bucks), but the parts are back ordered (along with all the G0704's) and i simply dont have enough cash to convert both to cnc, and i would like a G0602 lathe in the existing shop space it is taking up. If you are interested i could sell you it, i can even deliver fully assembled. I have the pull parts list as well for the R8 spindle conversion if you even wanted to go that route. I was going to go that route so i could use the same tooling on both of my mills. Anyways, let me know if you are interested.

[mhackney]

diyengineer, PM sent re: G0704

[photomankc]

The big full size guys are usually really well built and capable machines and lots of folks will emplore you to get one over a Chinese benchtop but you are going to have to look seriously at what it takes to get possession of one, and the space to house it and then the inevitable TLC required to bring it up to shape. They can be anything between undiscovered gems in perfect condition to needing to be almost rebuilt. If you don't have any way to get to them and look them over it's hard to tell from a picture. Then as others point out you need much beefier hardware to get the tables moving and that can add up fast. So can the electronics/electrical items needed to even get it running. If you can fit one though you have a machine that is not going to balk at much you can think of to throw at it.

In my case, the space available to me limited my options greatly. Even an RF-45 was really not something I would have the room for and the stairs and narrow path to the basement added more complications. The RF is also just a lot of machine to manage as a single person when you are talking about taking tables and heads off to work on it. Off course when it's time to make stuff that becomes a major advantage to the machine too and hopefully you spend more time making things than working on parts of the machine.

As far as the models of bench machine go I can't compare the X3 and BF-20 (G0704) because I have not had the X3. I did have the Harbor Freight X2 and there is no comparison in my mind. The X2 is limited by it's size and basic properties and I could push it too hard in aluminum much less steel. The table seems to get smaller with each new thing you try to get clamped to it and something needs adjusting all the time. The three set screw gibs alone drove me nuts. They were ALWAYS loose. I believe the X3 shares that item. The X2 did work though and with some extra mods I could have probably done a lot more with it.

The BF20 cuts aluminum like I used to cut plastic on the X2. I largely don't sweat what ever needs to be done in aluminum. Steel is still pretty easy so long as you follow the rules and don't get stupid but there you can start to run into the limits more easily. None of them are perfect machines but I was far more pleased in the finish and accuracy of the machine surfaces on my PM-25 than on the X2, I'm not as convinced about the electronics and motor. I ran into some of the same component failures that others have (driver board).

The Sherline stuff is nicely made and considered quite accurate but the problem will be one of size. They are very small machines and the parts they can work on are also small. I keep finding that it's not hard to come up with projects that stretch the legs on my BF20's travels and many would be very difficult or not possible on the Sherline. They are also slow machines. You have to work in shallow bites and small cutters and even with CNC you are not going to enjoy waiting around for it to complete larger work in small slices. If you are talking only small parts though it might be perfectly acceptable.

I'll speak as newb, take the advise you hear so often and get the biggest machine you can afford/fit. Things that you think are not going to be a problem for you while you are excited about making this one thing and ordering the machine are going to bug the hell out of you when it comes time to do it more than rarely. Simple fact is, you just can't have too much space for clamping, setup, vices, rotary tables, and travel. You want as much as you can get. You also never hear "Geez, I wish this motor bogged down easier".