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Mach Discussion => General Mach Discussion => Topic started by: Jugster on September 16, 2015, 07:06:07 PM

Title: Shop Fox Lathe Retrofit
Post by: Jugster on September 16, 2015, 07:06:07 PM
Hey Everyone!!!  Hope all is well!!!

I am getting ready to start a new project. I've been wanting a lathe to go with my two routers for some time. Would have liked to have a larger lathe, but my shop is so full I've decided to settle for a bench top instead. Besides all the parts I am making are small. I was going to buy a grizzly g0602, but an industrial supplier I use hooked me up with a shop fox m1049 at his cost. It was a great savings. There back ordered through mid October, but that gives me time to prepare anyhow. Here's my plan so far. Ball screws on both axi, replace motor add vfd, and control with csmio/ip.  Not sure which controller yet, depends on whether I use servos or steppers. On my original machine I changed my z axis to a larger stepper and digital amp and was pleased with how it ran. My large machine is servo and I love it. I know there are pros and cons either way. My question is what do you guys think?  Steppers?servos?  What size of each?  Now I do have two mrj2 drives, but I'm pretty sure the are 3 phase input side. I'm going to dig them out and check them later and I'll post specifics. I'm open to suggestions from everyone. Thanks for all the input.
Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on September 19, 2015, 08:21:16 PM
Wow guys. Nobody has any input!!!!  Everyone must be really busy :) :)
Title: Re: Shop Fox Lathe Retrofit
Post by: RICH on September 20, 2015, 07:40:01 AM
Just some things to consider:

- Purchase good quality ball screws and mount them properly such that backlash can be adjusted and minimized.
  I don't know how much room there is to install the X axis screw, but quality small ball screws are expensive.
  Said differently.......backlash compensation will not be required!
- All my machines are stepper driven, but, I only use a common controller mounted on a movable cart.
  May want to consider that to save some money and that would define motor type.
  Steppers are accurate and reliable when used appropriately, but, servo systems are a lot less these days.

Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on September 20, 2015, 10:23:30 PM

Lucked out and ended up with two mr-j2-20a Mitsubishi drives and matching motors from some obsoleted equipment at work. There only 200 watt but the have planetary gear reducers with a 19mm output shaft. I used some of these years ago on a machine build at work and I am thinking there a 30 to 1 reduction. We will find out for sure how they will do soon. Got software on pc  this weekend to hook to the drives and as soon as my cable comes in ill start working with them. I'll be using analogue speed control on this build. Should be interesting as everything else I've done has been step/dir.  Lathe is on back order till mid November now so I've got some time to work on the control side of things. What's your thought on Vfd brand. I have a haunyang on one machine and a delta b on the other. The delta b is a much nicer drive, but both seem to work just fine. I'm going to try and post pics on this build and probably need to move to a different part of the forum. Keep the input coming!!!!  Thanks
Title: Re: Shop Fox Lathe Retrofit
Post by: RICH on September 21, 2015, 09:24:29 PM
What's your thought on Vfd brand

Don't use one, :o well not yet, ??? waiting for the freebee to come my way ;).

Other folks with more experience on different brands may chime in.

Title: Re: Shop Fox Lathe Retrofit
Post by: BR549 on September 22, 2015, 09:10:40 AM
Using motors with a 30:1 reduction may mean you will NOT have much speed. Without speed you may NOT be able to do threading as it has to move fast enough to keep up with the spindle.

You may also run itno not being able to do the proper IPM to maintain a proper cutting volume.

Just a thought, (;-)

(;-) TP
Title: Re: Shop Fox Lathe Retrofit
Post by: Hood on September 22, 2015, 06:13:33 PM
Totally agree with TP regards the slow speed with 30:1 gearbox. , it will make paint drying look quick.

Title: Re: Shop Fox Lathe Retrofit
Post by: RICH on September 22, 2015, 08:45:22 PM
Since your going to do a conversion, define what you think would be the ideal system.
Look at a high end lathe of similar size and see what it is capable of doing.
Your have what you have in terms of the lathe weight, basic size restrictions, etc.
But you can set some bottom line that would be acceptable considering cost, accuracy, tooling, etc.
That can guide you in arriving at something satisfactory.

My nickel for what it's worth ................the lathe conversion is your dollar, :D

Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on September 22, 2015, 10:04:34 PM
You guys are absolutely right :). The gear boxes were actually 20:1. With the pitch lead screw I was looking at it would give you a whopping 30 in/ min at 3000rpms. That's not going to work. Lol. Guess I got caught up in what I had in those motors and drives. Free!!!  Continuos duty rating is 90.6 oz/in. Max torque is 269 oz/in. And yes Hood that would be like watching paint dry.  :) :). I can change the ratio no problem, but in doing so I don't believe I'll have the torque I need. I guess I'll have to go back to obsolete machine warehouse and see if I can find something else. Or just build stepper motor machine.   I'm going to build the machine regardless. Just working on a budget like most everyone here. What are your guys thoughts on the torque I need?  It's only a 9 x 19 machine , but it takes the same amount of torque to cut metal regardless of machine size.   Minus the additional torque to move the cross side of course. Thanks for everyone's input. Keep the comments coming.
Title: Re: Shop Fox Lathe Retrofit
Post by: Hood on September 23, 2015, 02:48:27 AM
On my wee lathe I have 50w on X and 400w on the Z.
The Z is direct drive and is still overkill for the wee lathe. The X is geared 2:1 and is just perfect.
I think if you had 2:1 or 3:1 reduction via belts you would have ample with 200w motors. You have to remember that servos and steppers can not be compared when looking at the torque figures.

What I did on my big lathe to find out what size motors I needed was to find out the torque to start the axis moving, I reckoned if that fell well within the continuous rating of the motor then I would have ample due to servos having at least 2x the torque in intermittent reserve.
 To measure the torque on the lathe I bolted a 1m flat bar to the ballscrew by the centre of the bar and positioned it horizontally, I then added weights until the axis moved, I was then able to work out the Nm required.

Obviously on a smaller lathe you are not going to manage to swing 1m on the end of a ballscrew but you could use a smaller bar and work it out or if you had a fine scale  torque wrench you could use that.
Reason I used a bar bolted on centre was so the bar itself balanced and only the weights themselves would act on it.

Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on September 23, 2015, 08:08:12 PM
As always guys, I appreciate the input.  I've never failed to be successful in the two machines I've done because everyone helps on this forum.  I think all you guys that have posted have always posted on my topics.  Even when I asked really dumb questions :) :) :)  I haven't been to warehouse to check yet but I believe I may have found another drive and motor if my memory serves me correctly.  Of course its Mitsubishi to.  I am going to move on with this build and try the timing pulley approach first, but If I need more torque I'll switch to the bigger drive and motor.  Good news is all the wiring will be the same since all the drives are the same besides watts.  Hood, I ordered the CSMIO/IP-A tonight. That should push me to the next level.  I've actually read some of the previous interfaces with  CSMIO/IP-A   on the MR-J2S drives on the forum and there is a lot of good information. Hopefully you guys wont get tired of hearing from me. Should have all my cables and terminal blocks in a week or so. Got the test circuit wired up last night on one drive.  I have an alarm on the drive, but I cant turn it off or jump out since I haven't received any of my cables yet.   I plan on getting the panel built and everything roughed in electrically before the lathe ever gets here.  Have a couple of months since its on back order.  If you haven't saw it already, check out the gunstocks topic on show and tell.  I revived it this weekend with the latest picture. Its really come a long ways.  Look forward to hearing from everyone!!!!
Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on November 12, 2015, 11:04:31 PM
Hope everyone is well.  Just thought I would give a brief update.  Finally have received all my terminal blocks and cables for the drives and motors.  Today I got my configuration software.  Turns out the newer stuff that I had wasn't compatible with the older drives.  Go figure. >:( >:(  Got a drive powered up and communication established.  I have to hardwire the estop and servo enable, then I should be able to start testing.  Controller is here now also.  Lathe is still on backorder, with no idea when it will be here.  May just cancel that order and go with a grizzly.  As I get time to  continue to work on this project I will update thread.
Title: Re: Shop Fox Lathe Retrofit
Post by: Jugster on November 23, 2015, 07:21:24 PM
Need a little input guys. Found out the lathe wouldn't ship till after the first of the year. I cancelled the order today and have decided to go with the grizzly. They have the g0602 and then there is the g0752 which is the vfd driven version of the g0602. Which is about 550 dollars higher. After doing a little research, I'm not sure I can buy a vfd and motor for the g0602 for any less than the difference between the two? I was however planning on putting a two horse motor and vfd on the g0602 if I bought one of those. What are your thoughts??  Anyone have a g0602?  I have movement on my servos now, and will be interfacing them with the controller soon. Any help is appreciated :)