Is variable speed on a grinder necessary?

Patrice Lemée;14741358 said:
It's still there Bill.
Click to expand...
No, it's not. My second post was in response to Karl B Anderson's post.
It said something to the effect that "reverse is to put metal back on that you didn't mean to remove."
It wasn't offensive.
 
Reversible is another thing I didn't know I needed until I had it.

You develop new techniques that utilize the capabilities of your tools. I was able to make a knife without all the cool stuff, but I can make a better knife faster with them. And it's more enjoyable when your tools do what you want them to rather than struggling with something that requires special eye squints and voodoo to work properly. Keeps my neck from getting stiff.

Nobody needs VS. And nobody's car needs AC ether...
 
Bill, the board was having some problems this morning taking a post - I spent 15 minutes on another thread trying to get a post to "take", but it never did. Perhaps that could have been the problem? I liked your "walked 2 miles to school, too. Uphill. Both ways." comment.

I've never used reverse on my variable speed grinder, couldn't think of any reason for it. After reading Nathan's comment, maybe I need to try reverse a few times. Might not know what I'm missing.

Ken H>
 
Don Hanson III said:
I profile on a wheel at near full speed, I grind with 36-80 grit belts at near full speed, but moving up to 120-400 grit I damn sure want to slow the belts way down!
Click to expand...

darrin sanders said:
If you're gonna leave your edges @ .015" or thicker then VS isn't necessary. If you're gonna grind your edges down to .003"-.005" with a 400X or 600X belt then VS is a NECESSITY. I can't take an edge that thin, with those belts, without burning the edge.
Click to expand...

Don and Darrin pretty much nail my thoughts on this. I crank the power to ELEVEN!!! for nearly all of my pre-HT grinding... which all fits into Don's 36-80 grit range. After HT, however, the BPM rolls way back and the kids start slow dancing.


Fred.Rowe said:
If you have only one machine VS makes sense.
Click to expand...

Fred also makes sense here. If I had dedicated machines for different tasks, I don't feel there'd be a need for VS on all of them. HOWEVER, with similarly sized motors, and proper switching on the load side of the VFD, I still might build them all as VS units. {In my best LotR voice} One VFD to control them all!!!
Both my KMG and disc are driven by the same VFD. :thumbup:


Karl B. Andersen said:
Not only does my new grinder have variable speed - it has reverse!!
Click to expand...

Reverse is super-handy. And, as mentioned above, I drive my disc with the same VFD as the KMG. Reversing is a MUST for the disc.


Lots of good responses on this thread. You guys are all aces in my book! :thumbup::thumbup:
Erin
 
I have been putting off retrofitting the reverse switch to my KMG for a couple of years which officially makes me the laziest man in all Christendom because it is, by all accounts, dead simple to do. ;)
Nathan the Machinist said:
Reversible is another thing I didn't know I needed until I had it.

You develop new techniques that utilize the capabilities of your tools. I was able to make a knife without all the cool stuff, but I can make a better knife faster with them. And it's more enjoyable when your tools do what you want them to rather than struggling with something that requires special eye squints and voodoo to work properly. Keeps my neck from getting stiff.

Nobody needs VS. And nobody's car needs AC ether...
Click to expand...
 
VS and reverse on a disc is the only way to whirl as Erin states. The last horizontal disc I built had both, plus a removable fence.

Good thread, Fred
 
Ken H> said:
After reading Nathan's comment, maybe I need to try reverse a few times. Might not know what I'm missing.

Ken H>
Click to expand...

behold the perfect ground plunge:

3.jpg~original


8.jpg~original


This is a 220 grit belt finish done at low speed on a reversing grinder. People seem to like it pretty well and it's really not a lot of trouble. Speed and direction control is everything.
 
For me personally, I have no need for a VFD. I have 3 grinders and have 1.5HP Leeson motors on all three. I learned with no VFD and thus adjusted and developed my own way of doing things on my machines so I do not miss what I never had. I have no plans to get a VFD either. I think that folks who never had one never miss not having a VFD. I won't try one either......I might want one then and start spending money again....LOL ! :) I think learn and get used to what you have and develop yourself with your tools....YOUR WAY ! There is no wrong way or wrong tool if the end results are good. I am just a garage builder with a good full time job so I am not under ANY time constraints I purposely "drag out" my builds to enjoy it . A maker working to make payroll and support a family will have totally different wants and needs :)
 
Last edited:
Yep Nathan - I remember you showing how to do those plunge lines using a platen with the radius end. I'd forgot the grinder was reversed. I can see where that would be best by far for that step. I did a set of 6 steak knives for the wife using your method, but didn't have reverse. I can see I need to put a reverse switch on my VFD.

Yes, I followed the thread where you did the CNC development on those knifes - that was a GREAT thread. I sent links to a couple of friends who are into CNC - they were impressed.

Ken H>
 
steelerfan88 said:
For me personally, I have no need for a VFD. I have 3 grinders and have 1.5HP Leeson motors on all three. I learned with no VFD and thus adjusted and developed my own way of doing things on my machines so I do not miss what I never had. I have no plans to get a VFD either. I think that folks who never had one never miss not having a VFD. I won't try one either......I might want one then and start spending money again....LOL ! :) I think learn and get used to what you have and develop yourself with your tools....YOUR WAY ! There is no wrong way or wrong tool if the end results are good. I am just a garage builder with a good full time job so I am not under ANY time constraints I purposely "drag out" my builds to enjoy it . A maker working to make payroll and support a family will have totally different wants and needs :)
Click to expand...

I was in the same frame of mind as you about a VFD - just didn't see the need for it with my step pulley setup. I can select 3 different speeds from low, medium, and high speed - what more could a person want? Well - then I got the VFD and WOW!! As I've said before - I've had to eat crow on that - VFD for me!!

Ken H>
 
Ken H> said:
I was in the same frame of mind as you about a VFD - just didn't see the need for it with my step pulley setup. I can select 3 different speeds from low, medium, and high speed - what more could a person want? Well - then I got the VFD and WOW!! As I've said before - I've had to eat crow on that - VFD for me!!

Ken H>
Click to expand...


Crow isn't so bad its a acquired taste .
 
Fist guy I know who did that was Matt Roberts (Longrifle on here) I have seen a couple of others do it with horizontal platen setups and on modified 4 inch belt sanders, including the guy who did the first water chilled platen setup that i saw. What end radius did you use for that, Nate?
Nathan the Machinist said:
behold the perfect ground plunge:

3.jpg~original


8.jpg~original


This is a 220 grit belt finish done at low speed on a reversing grinder. People seem to like it pretty well and it's really not a lot of trouble. Speed and direction control is everything.
Click to expand...
 
Ken H> said:
Yep Nathan - I remember you showing how to do those plunge lines using a platen with the radius end. I'd forgot the grinder was reversed. I can see where that would be best by far for that step. I did a set of 6 steak knives for the wife using your method, but didn't have reverse. I can see I need to put a reverse switch on my VFD.

Ken H>
Click to expand...

You don't need reverse to do it, I didn't at first. But there is a steeper learning curve because if you slip or mess up you can ruin the plunge. I run it in reverse if I have a lot of material to remove and switch to forward for finishing. You have to keep a firm hold on it, and the trick is to control the pressure spot on the blade so the radius doesn't touch the blade with any force unless you're actively grinding the plunge. Otherwsie it leaves a witness mark every time the splice comes around.

The last belt is run at a crawl, about the same speed as finish sanding by hand.

jdm61 said:
What end radius did you use for that, Nate?
Click to expand...

That used to be 3/8", but I've ground hundreds of blades on it and dressed it out quite a few times now, so it's not a true radius anymore, more of an elongated parabola at this point. Still going though...
 
Karl B. Andersen said:
Not only does my new grinder have variable speed - it has reverse!!
Which means I can grind standing on my head. :D

But I think I'll check with Don first.
He's forgot more than I know. :thumbup:
Click to expand...

pics or it didnt happen, I wanna see this inverted grind skill you speak of
 
Cliff Parker said:
Crow isn't so bad its a acquired taste .
Click to expand...

Cliff, Crow has never bothered me either. My mantra has always been, "While I like to have the answer, I'd MUCH rather have the right answer, even if it is from someone else".

Ken H>
 
Nathan the Machinist said:
The last belt is run at a crawl, about the same speed as finish sanding by hand.
.
Click to expand...

There ya' go - we'll still on the subject of OP as to why a VS is best.

Thanks Nathan for all your help and posts to the group - I've really learned a lot from you (AND too many other folks) sharing knowledge.

Ken H>
 
You must log in or register to reply here.
Back
Top