Surface grinder, adding power x-travel

[timo_gross]

I am thinking if it makes sense to put automatic x-travel, in some way, on a small fully manual surface grinder.
There are some ideas I stumbled across.

• connecting it to my shaper. Does not work, I do not have one
• Some sort of gear motor with a crank arm. Does not seem to be a very high end solution. I seemed to work for some people.
• A pneumatic cylinder.

I am experimenting with that right now. I am not sure if pneumatic is a clever idea. Maybe because air can compress, some vibrations or weird behaviour will be there. ( not intending do do heavy cutting anyway)

• Hydraulics. That seems to be the to-go solution in commercial machines. Not 100% sure why.

Hydraulic system would cost probably more than what I paid for the grinder . Not sure if that is worth it and if another solution for the small machine is as good.

• Fitting a timing belt and a motor to the existing hand wheel drive ( it is a rope drive)

What makes me suspicious is that it seems not very popular to put electric motors on the x-travel of grinders for some reason.

Any ideas or suggestions would be interesting, maybe also for other owners of manual grinders.

Greetings Timo

 

[cobweb81]

I had an old surface grinder that had X axis feed by an electric motor. They set this up with contactors to reverse the motor. It worked surprisingly well.

 

[ShopShoe]

I don't have your situation, but I am familiar with air cylinders in other applications and I think the motion would be too quick for a grinder. How to trigger the action for air control seems to be a complicated engineering project as well.

If you are looking at grinding a surface, would you manually step the Y-axis, or would you want to power the Y-axis as well and add a way of setting in a step-over dimension to the process? It would seem possible with electric steppers or servos on both dimensions.

I would be interested in watching a thread on this project.

--ShopShoe

 

[timo_gross]

I don't have your situation, but I am familiar with air cylinders in other applications and I think the motion would be too quick for a grinder. How to trigger the action for air control seems to be a complicated engineering project as well.

If you are looking at grinding a surface, would you manually step the Y-axis, or would you want to power the Y-axis as well and add a way of setting in a step-over dimension to the process? It would seem possible with electric steppers or servos on both dimensions.

I would be interested in watching a thread on this project.

--ShopShoe

I experimented a little yesterday after writing the post.
After about three hours I got what is on the video. All temporary: wires dangling around, power supply sitting on the floor etc.
I did not change anything on the machine, just used one exising hole, a clamp and some cable ties. The strikers for the switch I just put on the side of the grinding magnet after switching the magnet on.
A microcontroller (aka Arduino) detects when the switch is actuated, then switches the valve in the other position. I was actually surprised how trouble free it works.
The stroke of the cylinder is only 60 mm (little over 2 inches), but it was only ment as a first proof of concept ( 2nd hand cylinder did not brake the bank )

Needle valves to contol the air flow on each side of the cylinder allow manual adjustment of speed. Can be slowed down as much as required.
System runs at 2 bar. More speed starts shaking the machine from sudden reversing, so I did settle with what I got.

( ) Should replace the missing wheel cover for the grinder, but that is not fun and only becomes priority after a serious accidents.)

I already noticed after a few small test pieces, that not much is won by just the x-feed. A y travel must be added at some point. Possibly with a stepper motor. ( Or old school ratched mechanism; for the factor? )

Greetings Timo

 

[Eccentric]

Wow, that is pretty cool, and a nice finish!

 

[Mike Henry]

Would a stepper motor for the table feeds? Rob Renzetti posted little tidbits about a custom motion control he designed and installed on Instagram, which I think he tagged with #autoharig

That sure looks like a nice system.

 

[timo_gross]

Wow, that is pretty cool, and a nice finish!

Foto unfortunately looks much better than the reality. I would say "not horrible" and not worse than doing it entirely manual, so the pneumatic is not out of the equation yet.

Would a stepper motor for the table feeds? Rob Renzetti posted little tidbits about a custom motion control he designed and installed on Instagram, which I think he tagged with #autoharig

That sure looks like a nice system.

I do not think that it requires a very big stepper motor to move the y-axis, but maybe I underestimate it. The handwheel is quite big. I think I will just try the ones I already have. When they do not work, a good laugh at me and some toxic smoke is worst case. ( instead of the trial and error approach, maybe one could even calculate what is needed )
Fun fact: I did not "program" anything it ist just the Debounce example from Arduino IDE without any modifications.

Thanks for the Renzetti, hint. Trying to find it.

 

[Mike Henry]

Thanks for the Renzetti, hint. Trying to find it.

Try this:

https://www.instagram.com/explore/tags/autoharig/
The info seems to be mostly there, sprinkled out amongst a couple hundred short Instagram posts.

 

[Figor]

Here’s a few.

 

[ajoeiam]

Try this:

https://www.instagram.com/explore/tags/autoharig/
The info seems to be mostly there, sprinkled out amongst a couple hundred short Instagram posts.

Hmmmmm - - - - so it might be quite a bit more useful if some enterprising soul that was already on Instagram would collect all the useful posts and then drop that collection someplace handy - - - like here - - - maybe?

 

[Rocket Man]

Here’s a few.

I was going to suggest variable speed DC electric motor. Looks like that works.

I have a Reid #2 surface grinder with 6"x18" magnetic chuck that I don't use anymore it needs a new home.

Every time ADs pop up on the side it screws up my typing suddenly it will not type until I click the pointer back to the end of the last word. I need to switch browsers to AD blocker.

Now I have AD blocker wow it is easy to type now.

 

[Mike Henry]

Hmmmmm - - - - so it might be quite a bit more useful if some enterprising soul that was already on Instagram would collect all the useful posts and then drop that collection someplace handy - - - like here - - - maybe?

I'm not sure that would be ethical. Aside from the question of ethics, it would be a fair amount of work to collect info from the various Instagram posts into some sort of coherent story. Anyone serious about building something similar can easily access the posts themselves.

 

[Bentwings]

Would a stepper motor for the table feeds? Rob Renzetti posted little tidbits about a custom motion control he designed and installed on Instagram, which I think he tagged with #autoharig

That sure looks like a nice system.

when I was just starting working in machine shop there was a large surface tinder that had a power y axis . I think it might have been mechanical I remember just adjusting it to a number it seemed it just moved a given amount you could vary the step and speed. It was quite a big intimidating machine there was more than a few accidents with it. I had justvrefinished precision grinding the mag chuck. It was working perfectly . Night shift came in and the next day there was about a 2” wide groove carved out of the chuck about 3/4” deep . It essentially ruined the chuck. There was the remains of a large wide grinding wheel all over plus a very large dent in the splash pan at the end of the machine. Apparently they tried to adjust the power down feed while it was running and either went to far too fast or ju pre set it without testing. I don’t remember the power but at least 10-15 hp electrical motor . It never did really precision work while I was there . So I’d be very careful
Byron adding power feeds.

 

[Joseph Comunale]

I know its way over kill ( But what's the point in designing anything if you can't over design it???) - but - why not an inexpensive CNC drive?
There are a lot of instructable articles on doing this with GRBL boards (think $35 motherboards that drive 3D printers) and inexpensive stepper drivers? You could control this to a very fine degree - as well as create diagonal finishing patterns, etc. I've been thinking about doing this to my surface grinder for a while. The loads to drive the rack and pinion of the surface grinder are minimal at best. Heck, create a Mach3 wizard to drive it, maybe?

 

[Bentwings]

I know its way over kill ( But what's the point in designing anything if you can't over design it???) - but - why not an inexpensive CNC drive?
There are a lot of instructable articles on doing this with GRBL boards (think $35 motherboards that drive 3D printers) and inexpensive stepper drivers? You could control this to a very fine degree - as well as create diagonal finishing patterns, etc. I've been thinking about doing this to my surface grinder for a while. The loads to drive the rack and pinion of the surface grinder are minimal at best. Heck, create a Mach3 wizard to drive it, maybe?

I certainly can’t criticize your project just be careful. Design n safe guards if you can . Sometimes a wide wheel can be used to take wide shallow passes.. maybe add a wheel question to the program
Byron

 

[timo_gross]

I know its way over kill ( But what's the point in designing anything if you can't over design it???) - but - why not an inexpensive CNC drive?
There are a lot of instructable articles on doing this with GRBL boards (think $35 motherboards that drive 3D printers) and inexpensive stepper drivers? You could control this to a very fine degree - as well as create diagonal finishing patterns, etc. I've been thinking about doing this to my surface grinder for a while. The loads to drive the rack and pinion of the surface grinder are minimal at best. Heck, create a Mach3 wizard to drive it, maybe?

Only progress so far, is an ugly not very well made wheel guard. Product of Friday.
I have not fully decided, make something semi automatic or just leave it fully manual. But there seems to be some interest in it.
I am not sure what advantages CNC would have. I imagine to utilize CNC, the mechanical system must be very repeatable. The next problem would be to program the thing .

The GRBL is a sort of interesting toy. One downside I see, it is very limiting. If the over design gets out of control. GRBL becomes complicated, if the feature creep sets in. (I guess)
We will see, what I come up with.

 

[timo_gross]

I certainly can’t criticize your project just be careful. Design n safe guards if you can . Sometimes a wide wheel can be used to take wide shallow passes.. maybe add a wheel question to the program
Byron

Yes, I agree. To be honest grinder appears to be so "cute and harmless", cutting forces are not so high, they do not make horrible noise.
High risk to underestimate those beasts. A part tips on the magnet, small parts get hot and suddenly launch, hell brakes loose quickly.

Let the wheel stop before changing anything on the magnet. trying to stick to that rule.

Greetings Timo