PDA

View Full Version : Surface Grinder Fixtures



BigJohnT
11-28-2012, 06:20 AM
What kind of fixtures and grinding aids do you guys find most useful for a surface grinder. I have a B&S 6x12 manual grinder. I'm adding CNC to the X and Y just do I don't have to crank the wheels.

Photos are most helpful.

John

PixMan
11-28-2012, 07:49 AM
I use precision angle irons, a small sine bar vise, steel parallels, pass-thru magnetic parallels, a spin-dexer, 5C collet blocks, a radius/angle dresser, and the more wheel choices the better.

To be clear, is it the wheel elevation and cross feed that you are "automating", and would still have to crank the table reciprocation by hand?

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/422322392_photobucket_47220_.jpg
http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_1038-r.jpg
http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_0301-r.jpg

BigJohnT
11-28-2012, 08:27 AM
The V blocks and 123 blocks pass the magnetic force through? I've never seen any like that...

The first thing I'm automating is the X axis as that will be the big plum to pick and no more cranking back and forth, next will be the Y axis. I don't have any plans for the Z axis. My thoughts are put a part in there, touch off and set my Z then press the start button and the table will move through the cycle while I'm off taking a nap or something.

Come to think of it I have a square and hex 5c collet holder that I can use if needed...

John

Mcgyver
11-28-2012, 09:28 AM
The first thing I'm automating is the X axis as that will be the big plum to pick and no more cranking back and forth, next will be the Y axis.


what Pix is getting at is the Y axis is the vertical motion of the wheel. Machine tool axis are always based on the axis of the spindle being Z.....on a surface grinder, the in and out of the table toward and away from you is the Z.

As for tooling, most useful is a mag chuck, precision angle plates, grinding vise, magnetic parallels and V blocks. Worth having, but less used (at least in my shop) sine table, pin grinder, radius & angle dresser. there are tool grinding attachments but I have a T&CG so don't do that on the surface grinder

Flood coolant is a HUGE improvement as well if you don't have it.

I hope you detail the build and post lots pics and description....lots of us with manual grinders would be interested in seeing the project develop

amateur
11-28-2012, 09:40 AM
Are "pass-thru magnetic parallels" needed on a electric/magnetic chuck ?

Jimmer12
11-28-2012, 09:58 AM
Are "pass-thru magnetic parallels" needed on a electric/magnetic chuck ?

If you want to set your steel work piece on top of the parallels or v blocks then yes they are required. Regular 123's or v blocks wont put enough magnetism through to hold the piece.

BigJohnT
11-28-2012, 09:58 AM
what Pix is getting at is the Y axis is the vertical motion of the wheel. Machine tool axis are always based on the axis of the spindle being Z.....on a surface grinder, the in and out of the table toward and away from you is the Z.

As for tooling, most useful is a mag chuck, precision angle plates, grinding vise, magnetic parallels and V blocks. Worth having, but less used (at least in my shop) sine table, pin grinder, radius & angle dresser. there are tool grinding attachments but I have a T&CG so don't do that on the surface grinder

Flood coolant is a HUGE improvement as well if you don't have it.

I hope you detail the build and post lots pics and description....lots of us with manual grinders would be interested in seeing the project develop

I had mill on the brain and not lathe, of course your correct I'm CNC'n X and Z axis. I have a couple of toolmaker vises and the usual parallel sets. Yes I plan on detailing the conversion. The X will be rather easy as it is out in the open and easy to get to, the Z is inside but plenty of room. I don't see needing a lot of power to run this with nema 23 double or triple stack steppers. I may use my ardunio at first to run the X stepper drive. Probably get a Gecko G251 stepper drive.

John

KiddZimaHater
11-28-2012, 06:11 PM
Parallels, Magnetic Vee's and Blocks. 5C Spin-indexer (or even better a HARIG Grind-All), Radius dresser, Angle dresser, and Sine Vise is a must.

PixMan
11-28-2012, 10:00 PM
I don't think it's easy to automate the X axis reciprocation. When I worked for Norton company they had a Nicco dual mode creep feed/reciprocation surface grinder. When in creep feed mode it used a ball screw to feed the table at (obviously) slow rates. When in reciprocation mode you would shift a lever that dropped out the ball screw and engaged a belt drive. Or something like that. I'm not 100% sure because they wouldn't let me take the machine apart to find out. ;)

I would be concerned that a stepper motor driving the reciprocation would leave a horrible wavy finish. That may be why most tables are driven by belts, or in the case of my Kent grinder, a cable drive.

BigJohnT
11-29-2012, 06:20 AM
I don't think it's easy to automate the X axis reciprocation. When I worked for Norton company they had a Nicco dual mode creep feed/reciprocation surface grinder. When in creep feed mode it used a ball screw to feed the table at (obviously) slow rates. When in reciprocation mode you would shift a lever that dropped out the ball screw and engaged a belt drive. Or something like that. I'm not 100% sure because they wouldn't let me take the machine apart to find out. ;)

I would be concerned that a stepper motor driving the reciprocation would leave a horrible wavy finish. That may be why most tables are driven by belts, or in the case of my Kent grinder, a cable drive.

I won't be doing creep feed so no worries there. In fact it will be a simple task to connect a stepper to the belt drive now connected to the wheel. The stepper will give me a more consistent feed rate than I can possibly do by hand. The conversion will be simple compared to what I have done so far...

John

Mcgyver
11-29-2012, 09:48 AM
I would be concerned that a stepper motor driving the reciprocation would leave a horrible wavy finish. That may be why most tables are driven by belts, or in the case of my Kent grinder, a cable drive.

I've seen some new stepper motor driver that spin silently even at thousands of rpm with seemingly no heat ....in other words the behave more like what I think of as servo behaviour (which in essence they are). They're a far cry from the noisy clunky action of a stepper. Wonder what the Gekkos are like now?

Even if it was the older style, if you are belting it to the handle it wont imo matter

BigJohnT
11-29-2012, 10:18 AM
I've seen some new stepper motor driver that spin silently even at thousands of rpm with seemingly no heat ....in other words the behave more like what I think of as servo behaviour (which in essence they are). They're a far cry from the noisy clunky action of a stepper. Wonder what the Gekkos are like now?

Even if it was the older style, if you are belting it to the handle it wont imo matter

I use the Gecko 203v's for most stepper projects and the movement is super smooth with the mid range morphing from micro step to full step. The G251 is a 203 but for lower voltage, I don't anticipate wanting 500IPM like my plasma cutter so I'm thinking the G251's will fill the bill. I'll use a 48v power supply and that will be plenty fast.

Most steppers will run 1000-1200 rpm but are limited by something like inductance or something like that as to how fast you can go. If it is running cool it can't be a normal stepper it has to be some hybrid motor...

Yea the plan is to put a timing belt from the stepper to the back of the hand wheel for the X axis and use about 4 -1 reduction on that or use a 10-1 gear reduction... more to ponder.

John

Mcgyver
11-29-2012, 10:44 AM
I think your plan is a good one and should work well. How are you handling the acceleration/deceleration on the direction change?


IMost steppers will run 1000-1200 rpm but are limited by something like inductance or something like that as to how fast you can go. If it is running cool it can't be a normal stepper it has to be some hybrid motor...


just for interest sake, there is a new breed of controllers that let you run regular stepper motors at up to 4k silently or stopped and holding.... and you can put your hand on them they are barely warm. They use encoders and pid controls so in essence are servos....but they are just a 100% standard stepper with a rotary encoder and very cool controller and software.

BigJohnT
11-29-2012, 11:23 AM
Acceleration/deceleration is handled in the software.

Neat, who makes that controller?

John

BigJohnT
11-29-2012, 03:22 PM
I asked a well known engineer that makes cnc controllers and automation drives and a bunch of other stuff about the 4k stepper ( I just copied him on what you said) and was not surprised at his answer.



JT: using step motor as servos has been done for a while. They still have the same torque/speed curves that the stepmotor at a drive given voltage however. They are good for slow speeds where you don't want to use any gearing and want the standard servo advantages of low idle power and higher accuracy

4000 RPM is possible (and they stall like a servo, that is if you overload the they will stall, but restart when released) but you will have minimal torque at 4000 RPM

That is a step motor can be run just like a AC servo (though 2 instead of three phase and 50 poles instead of 2/4/8)
Yeah its a true servo, it cannot stall in the step motor sense (and only enough drive current is supplied to move to the desired position)
but step motors make poor servo motors efficiency wise and the high drive frequencies make the drive more complicated than say 2-8 pole a 3 phase drive


My take on it is while what you said is true, the actual applications that can use that type of drive are not the usual CNC applications and the drive would be much more expensive than a stepper drive.

John

Sparky_NY
11-30-2012, 08:51 AM
Keep us posted John. I have a friend who has a grinder he asked me about cnc'ing. He bought it unseen, thinking it was a powerfeed grinder but it was not. To make things worse, the grinder has all metric calibrations!! He has been a mold maker for nearly 40 years and those metric calibrations are sure to cause bad mistakes. Cnc'ing a grinder does seem like it would be a easy retrofit compared to mills and lathes.

Spin Doctor
11-30-2012, 11:04 AM
Back to fixturing, jigs for grinding tool bits to specific angles (ie threading tools etc). Special jigs for grinding multiple parts also come in handy on occasion.

outback
09-10-2013, 07:33 PM
The fixture below is a "Harig Knockoff". I used them for most of my career. I made one when I first bought my 6 x 12
Harig surface grinder. The cylindrical grinding attachment also indexes. It is a must have.

http://img.photobucket.com/albums/v30/jglass/cylattachment0002.jpg (http://smg.photobucket.com/user/jglass/media/cylattachment0002.jpg.html)


I use my surface grinder for a cut-off machine. I use abrasive wheels .040" wide. Work great for notching a larger piece of steel. Better and cheaper than converting the a step into chips. The useful reminant is also a bonus

http://img.photobucket.com/albums/v30/jglass/cutoff0004.jpg (http://smg.photobucket.com/user/jglass/media/cutoff0004.jpg.html)

I made the tool bit grinding fixture many years ago. The goal was to keep from burning my fingers while sharpening
tool bits on a pedestal grinder. I grind all my tool bits with the fixture now.

http://img.photobucket.com/albums/v30/jglass/bitfixture0001.jpg (http://smg.photobucket.com/user/jglass/media/bitfixture0001.jpg.html)

I would think twice about making a 6 x 12 grinder into a power feed machine. For precise work I would much rather run
a grinder manually. Power feeds on large grinders are fine but I would keep the 6 x 12 manual.

Jim

yul m6
09-11-2013, 02:25 AM
I am also considering automating my 6x12 Boyar Schultz SG. Wouldn't a geared variable speed motor (AC/VFD or DC) be a better choice for the X drive.
What range of speeds and feeds are you aiming for John?

Breze
09-11-2013, 02:39 PM
These post are from when I converted the long axis on my grinder, might be of some help, maybe not,

http://bbs.homeshopmachinist.net/threads/58453-Converting-a-manual-suface-grinder-to-automatic-longitudinal-table-movement

http://bbs.homeshopmachinist.net/threads/58632-Grinder-Table-Automation-The-Rest-of-the-Story