[osdhillon]

Hi,

i am looking into buying a mini mill and a lathe (Bench Top). I will be converting it into a CNC machine later. I need help in determining which one to buy. For lathe what is the most optimum size, i.e. given it is bench top, what is the most common and tested size of lathe which works well without any problems. some lathes do specify for longer workpiece, but are not that strudy.

Please pass on your valuable suggestions and experiences.
Thanks

Onkar

[Torsten]

A often asked question that always gets a smile from me.
A china mni mill and mini lathe costs less then $1000.- and
that is what you get.
With some tender loving care, some modifications and some time
invested they will work pretty good for most hobby people.
The next step up in quality made by some western countrys
will cost in exess of about $30,000.- and are the better choice
in workmanship, materials and longvinity.
For a industrial application that will run the machines 24/7 the
decision is easy.
What is it you want those machines for?
Possible part size?
You can allways make a smaller part on a larger machine.
The other way around don't work so good.
Good Luck

[Halfnutz]

I have done ALOT of research, here is my two cents:

The Sherline or Taig if you want to do REALLY LITTLE stuff. Cost less than 600.00

If you are really strapped, the Homier 12 spd. mini is a great deal at 299.00, but this style mill is not very accurate and may not be a good choice for a cnc conversion, because the money invested may ultimately end up wasted. If you want a manual mill just to fool around with it is the best bargain.

Next step up is the Rong Fu/Enco/Grizzly1006/7/HF33686 4.5 in collum style mill at around 1000.00. They need alot of work in accuracy and stability but once retrofitted are nice performing machines.

Next step up and probably best choice if you can afford it is the square collum Lathemaster mill at around 1400.00 Grizzly also has a nice version of this mill as well as Enco.

As far as lathes the Sherline for little , accurate stuff. The 7x10 can be had for under 400.00 if you look around. The 9x20 is next choice at 700.00-900.00, then you jump up into really big machines that I cant help you with.

Sherline is great stuff but SMALL. All the rest is Chinese and SLOPPY unless you got BIG MONEY. Just keep poking around here and on the other sites and start saving some money, then decide how much you can afford to spend and that will determine what you buy because you definately get what you pay for. If you can afford it get a German round way lathe at around 3500.00, there fantastic machines for the money.

Good luck & go BUY SOMETHING to get started. you wont regret it, metalworking and machining is a lot of fun and very challenging.

[osdhillon]

Halfnutz

Thanks for your valuable input. What do you think about the following:

Milling: Bench Mill from PRO-CUT (Acu Cut) 8"X28" bed. It is a milling and drilling( 1.5: capacity)machine and DRO can be bought with it. The price is $ 1488.00 Without DRO and Base.

Lathe: Lathemaster 9X20" or Jet USA 9X20" . This is the size I am looking for. I am looking for accuracy and will be converting both machines into CNC.

Your help in finding a right machine is appreciated.

thanks
Onkar

[sundy58]

I haven't been able to find the mill you are talking about. I use a Rong Fu 40. Round column 2 axis DRO from Enco for about 3500. Wish I had the RF 45 with the square column. I'm planing on ball screws (not CNC) to make getting to .0005 easier. Other than not enough Z been very happy.

[osdhillon]

Production tool supply .
Check this link http://web.thetools-store.com/monthly_flyers/ms_52.pdf
This mill is about $ 2945 regular with DRO and base. It is currently on sale for $1900 with DRO and base. Without base and DRO regular price is $1488, and is on sale now for $899.00. It is a round column type . I had a chance to look at it in the store. Looks a fine machine, it had ACU-RITE DRO on it. Have a look and please let me know yor opinion about it. I am looking to a buy a reasonably good Mill and lathe for my home.

Thanks

[JFettig]

Sundy, by upgrading to ballscrews, you will have major problems with stuff moving on its own. you would have to lock axes constantly and might be a pain.

I have the mini mill from homier, I wish I had a sq column mill like the RF45, or the industrialhobbies mill.

Jon

[sundy58]

Jon,
I thought the ballscrews would get rid of the .0005 to .0015 jump I get when I tighten down the axises? When I try for .0005 it can take a couple of minutes of locking down and adjusting to get the reading I want. I was looking for what ballscrews to buy when I came across this and I don't want to hijack the thread.
But since it's not coming out of my pocket I would be willing to pay for a bolt in solution. (non CNC)

[Halfnutz]

Ballscrews are ideal for a cnc retrofit because of two reasons. They are accurate (ie backlash adjustable down to zero) and they are extremly efficient (ie NO FRICTION). Since a cnc upgrade normally has some mechanism built into the system (ie holding power or braking power in the servos or steppers) to hold the table where positioned ballscrews are great. If you are only interested in accuracy a good ACME screw upgrade will give you improved resolution, but I dont know how much exactly. (the screw mfg. will have specs.) With ballscrews and no brakes everything might shake out of position too easily.
As far as the Acu-Cut mill, it looks like a Jet or a Rong Fu, at Those prices it is a good deal. I have one from Harbor, the same thing, and I love it. It is very powerfull and after I went through it and tightened it up it cuts very well. A lot of people say not to buy the round collum, I geuss if you have the extra money it makes sense, but if you cant afford the 1500.00 price tag what choice do you have? If you want to cut metal for less than 1000.00 its the only thing out there in a reasonable size, big enough for full size tooling that is.

[JRouche]

This mill is about $ 2945 regular with DRO and base. It is currently on sale for $1900 with DRO and base. Thanks

Hi, if you are gonna convert it to CNC don't get the DRO, you wont need it.

Now, if you do have $1900.00 to spend for the mill I would consider one of the dovetail column mills that are based on the Rong-Fu 45 design. You can get one for around 1400 to 1700 dollars.

If you are gonna convert it don't worry about getting the "top of the line", brand named, Rong-Fu. The stuff that might make it nicer than the others is going to be removed and replaced with CNC stuff anyway. You are interested in the castings not the bolt on stuff.

I bought an Enco when they were on sale and had free shipping. I bought a CNC conversion kit from Industrial hobbies and am converting it now. I will document the conversion on my web page with pictures and documentation (to be announced).

JRouche

[Torsten]

The Mill/Drill is a RF21 type same as sold be Enco,HF,Jet and all the others.
I am converting one right now, a good machine that has been around for
a few generations a solid machine with a wide range of applications
For CNC in mind you don't want any of the extras on there like DRO,Powerfeed or
Quilldrive that is sometimes offered.
Just get the barebone basic model.
I believe the Lathemaster 9x20 would make a good candidate for CNC the
difference of the larger 5." Chuck is wellcome.
I own one of the other USA 9x20 that seam more common around here, they
only come with the 4". Chuck and a quickchange gearbox wich is just stuff
that needs to be taken of when converting to cnc.
It is good to have for a manual machine however.
Remember when budgeting for you machines that you will likely need to buy
additional tooling before you will be able to really use them.
Plan on spending at least another $1000.- for this over the first few month,
buy what you need when you need it not what you may be wanting just in case,
is the moto I use and it served me well.
Good Luck

[osdhillon]

Jrouche

The mill by PRO CUT (Production Tool Supply) Is for sale for $ 899 (Without DRO and base). It is a round column one. The square column one is atleast for $1400 as you have said. What are the major drawbacks of the Round column. I am definately converting it into CNC . Is there something I should be aware of?

Torsten
Lathemaster 9X20 seems to be a good machine (It is not is stock). What do you think of Jet USA 9X20"

Regards
Onkar

[Halfnutz]

Yes there is definately something (many things) you should be aware of. One of them regarding the round collum mill in respect to cnc is this:

As you get into serious machining you will be required to make multiple tooling changes for the same part. The round collum mill has no reference or positioning system for its radial or rotary movement. It also lacks the same for its head inclination on the main collum. When you change cutting tools you must get back to the EXACT same X,Y,Z co-ordinate points that you started from. There is NO system on the round collum mill for doing this, other than manually re-positioning the end of the cutter as best you can. HomeCNC at www.homecnc.com has come up with a way to get around this delemna that looks like it will work for me, but there is no real solution to the problem, only ways of getting around it, as far as I know. This is the reason you will hear many times over that people do not like or recomend the round collum for conversion.
My budget is just too tight to afford the additional expense, so I am going with the round collum.

[Torsten]

Jrouche

The mill by PRO CUT (Production Tool Supply) Is for sale for $ 899 (Without DRO and base). It is a round column one. The square column one is atleast for $1400 as you have said. What are the major drawbacks of the Round column. I am definately converting it into CNC . Is there something I should be aware of?

Torsten
Lathemaster 9X20 seems to be a good machine (It is not is stock). What do you think of Jet USA 9X20"

Regards
Onkar

That is the Lathe I have Jet BD-920N it is a good machine but will need
the same modifications done to make it even better just like the other brands.
Having done them I am very happy with this machine.
In the future I plan on a cnc retrofit for it, a lathe is a much different animal
in this regard then a mill, just having 2 axes under cnc controll is not nearly
as usefull you also need the tailstock moving with a turrethead under controll
Barstock feeder spindle encoder etc..
Also incorporating this while retaining manual controll is a engineering nightmare.
I will worry about this when the time comes.

My Mill/Drill a Jet JMD18 round column almost done with the cnc retrofit a
good machine that performs very well.
There is some controverse going about square verses round column the way
I see this they are just different machines each with there strenght and weaknesses.
A often quoted loss of position when moving the head of the round column
machines up and down in situations where the 5." inch quilltravel is exeeded.
Yes that is true, a inconvienience requiring you to redial your work in, but
it is also true that this is a very rare situation.
A expirienced operator with the right tools for the Job will run into this only
on rare occasions because you will plan better on avoiding this.
The typical beginners scenario where this happends is when using a long
drill held in the long stock 1/2 drill chuck and the next tool is a short endmill
held in a standard collet close to the quill.
Some advantages of the round column is this very ability to turn the machine
head to accomodate your work.
if you have a carefull mounted long part dialed in and clamped to your table
but end up not having enough travel to machine the entire lenght of it you
will be able to swing the head doing one side the swing the other way to
finish the remainder thereby nearly doubling your machines reach.
Also very long parts can be clamped beside the table on a angleplate
where they may go down close to the ground with the head turned you
can easyly accomondate your work.
Square Columns don't do that you have a fixed rectangular workarea.
For cnc it is nice to have a larger controlable Z Axes.
What it boils down to for me is the round columns have more flexibilty for
od shaped parts that can be machined under marginal conditions while the
square columns offer more ideal conditions within there travel envelope.
Really depends on what you want there are happy people on both sides.
Good Luck

[Halfnutz]

I agree with you Torsten. I like the round collum and loved the price. There is no reason why it wont work for my basic requirements with some ingenuity and planning. I would not hesitate to reccomend the style to anyone with a budget restraint but Im new to this and have a lot to learn. Same for the 9x20. Its the best thing in its price range that I have found. As far as the Jet brand, I think the mills and lathes (these models) are all the same. I couldnt detect any real difference between brands. Jet is sometimes higher in price, but they are a rock solid company thats been around forever. There is a lot to be said for that.

[osdhillon]

Thanks Everybody for the input.
I finally got Pro_Cut Round column mill ($899 free shipping) and Jet 9X20" lathe for $1338.
I am going to play with it this weekend, machine some parts badly needed for my CNC Router. In very near future I am converting these machines into CNC. Hope there is a lot of info on that on CNCZone.
What extra tooling should be I looking for? Any input on it and CNC convertion is welcomed.

thanks

Onkar

[JRouche]

Sorry I didn't get back to you, busy, busy, busy...

Glad you got a mill. You will have fun with what ever you get cause it's yer baby. There are plenty of folks who have converted the mill and are willing to help you. Try the search function, it will bring hours of reading. JRouche

[osdhillon]

Torsten
Quote:
That is the Lathe I have Jet BD-920N it is a good machine but will need
the same modifications done to make it even better just like the other brands.
Having done them I am very happy with this machine.


Can you please share your modification details.

[Torsten]

Torsten
Quote:
That is the Lathe I have Jet BD-920N it is a good machine but will need
the same modifications done to make it even better just like the other brands.
Having done them I am very happy with this machine.


Can you please share your modification details.

One Modification I consider essential is for the upper slide
support Clamp it is like a big washer with 2 bolts diagonally
that clamps down the upper slide.
It allows for to much movement in the upper assembly and
couses a lot of shatter during heavy cutting.
The modification is a 4 bolt upper support clamp that that you
can find described in detail at this group.

http://groups.yahoo.com/group/9x20Lathe

Most people like myself have made some variation of this
clamp for there machines.
There are lots of writeups on this with some drawings too.
The point is to support the upper slide as good as possible
by making this thick enough to reach all the way up until it
meets the underside of the slide.

Some other not so urgent things I have done is to add a
Thumbler Reverse gearmechanism that allows me to also
cut left handed threads.

And I added a Quickchange Toolholder that also needed
some modification to fit properly.

There are a lot of very useful modification that could be done
described at the lathe Group.
Just do what is important for you first over the years your
machines usefulness will greatly improve by some of the
modification you incorporate.

I have stopped making improvements for now because I got
what I need and have to evaluate first about what will be
useful for a cnc conversion.
There are very differrent requirements and a lot of the components
have to be removed or rendered useless for cnc.

After all I bought the lathe to make some of the parts for retrofitting
my Mill/Drill.
Just let me know if you have any questions.
Good Luck

[osdhillon]

TOrsten

Thanks. I will be opening my mill and Lathe today and by the weekend It will be running.

Onkar