how was it i could make knives before the KMG

butcher_block

butcher_block

Joined
Dec 6, 2004
Messages
6,212
WOW
after the 1050 mile round trip deker and i went on over the weekend
she's is wired up and running and while the VFD wolnt over drive real far its great
i cant believe the night and day difference ssoooooooo smooooth
any how thanks deker for driving the baulk of the trip :thumbup:
butch
 
Heh...more like 1080 miles for me :)

Glad to hear you got it up and running. I was worried that you'd end up in limbo for a few days just staring at your KMG and wishing the wheels would spin.

At some point I do need to get a photo of your KMG next to my clone. I had never seen one in person before Saturday and it turns out I over-estimated how heavy a lot of the pieces should be. I will now have to dub my grinder the "HBKMG-XL" or "HBKMG-XTREME" or something. I think I have you for about 50% in mass ;)

Now, GET TO WORK!

-d

P.S. I may call on you to swing over Friday evening or Saturday to help me unload and place the power hammer Butch. The concrete should be set up enough by then.
 
butcher_block said:
WOW
after the 1050 mile round trip deker and i went on over the weekend
she's is wired up and running and while the VFD wolnt over drive real far its great
i cant believe the night and day difference ssoooooooo smooooth
any how thanks deker for driving the baulk of the trip :thumbup:
butch
Click to expand...

Butch, which model did you get?

Thanks!

Andy
 
deker said:
P.S. I may call on you to swing over Friday evening or Saturday to help me unload and place the power hammer Butch. The concrete should be set up enough by then.
Click to expand...

Scratch that...Kerry will be out of town until the friday after thanksgiving...no hammer for me :(

Andrew: I believe it's a KMG-1 with the old style platen.

-d
 
What is this machine..? Where did you get it..? I try to keep track of them...especially the older ones.

-Rob
 
rfrink said:
What is this machine..? Where did you get it..? I try to keep track of them...especially the older ones.

-Rob
Click to expand...

Wow Rob, I didn't realize we drove right by you! We would have asked if we could crash on your couch if we had realized. :D We were in Oxford, OH to pick this one up from a man named Hurl.

-d
 
hey dek thanks for keeping up with the thread i was grinding you slacker
kmg1
dek BTW the readout is Hz not %

rob hell of a grinder you make there
devil gets my soul before the grinder finds the way out of my shop
now im craving a small wheel set up
 
butcher_block said:
just looked at the other motor if i read it right its a 3500 rpm
Click to expand...

It'll be worth figuring out the new shim heights to mount that one up. Given that your VFD is limited to 120Hz, your 1725RPM motor will only give you a max of 3450RPM ( RPM * (MaxHz / 60) ) or 3611SFPM of belt speed ( (Drive Pulley Size * 3.14 * RPM) / 12) or in your case (4*3.14*3450)/12 ). Being able to run a 3500 RPM motor @ 120Hz will give you 7000RPM Max or 7326.333SFPM. Really, I'd say a max of ~5000SFPM would be good enough for even the heaviest hogging. When I don't have to cook dinner I'll figure out what your new Max Hz setting should be in order to cap you at ~5000SFPM.

-d
 
hmmmm.... I have a few thoughts about this.

The VFD runs in a constant torque mode from 0 to 60hz...then it goes into a constant HP motor above 60hz (base speed of the motor).

If you run it at 120hz you double the motor speed....but since it is in a constant HP mode...you also cut the torque in half. If you are planning to do your heaviest hogging at this speed...you'll only have half of the torque.

A better solution would be to make run the motor near it's base speed (which is the peak HP and peak torque...@ approx 60hz). Use a different pulley ratio in between the motor and grinder to get the belt speed that you want. You'll be hogging at the highest belt speed and you'll want all the power and torque that you can get...which happens at 60hz.


So, if you want a belt speed of 5000ft/min ..then spin the drive shaft at about 5000 rpm. To do this with the 3500 rpm motor you need a pulley ratio of 3500/5000

which is the same 3.5 to 5.0 .....use a 5" pulley on the motor and a 3.5" pulley on the grinder.

This is just the way that I would set it up....and I never argue with success.

I just love tinkering with machinery!!!

Have fun!

Rob
 
welll maybe i can get tot hoggin and see if i even want more speed
after all i am stepping up from a:o delta 1x42:o
 
Butch, with the power you'll have with the new grinder compared to that teenie weenie thang you're used to, you'll probably find that "sh*t happens" a whole lot faster. Not nice sh*t, either. IMO you spend more time with your grinder going slower rather than faster.

Rob told me, when I bought mine, to run a 3.5" motor pulley and a 2.5" drive with my 2500 RPM 2HP VS DC (3500RPM at the grinder). I almost never run it at 100%, more usually 50-60%, sometimes as low as 30. It's always been fast enough, with a whole lot of power. Torque rules, especially flat grinding. I have a lot of control, too.

The other side of this is if a blade gets away from you. Force= mass x velocity. You run a grinder like a bat out of hell and a blade gets loose it whacks you or sticks you a lot harder.

Just my $.02 on the subject. Have fun, you're going to love it even more with time.
 
so far i have run it up to about 80 hz and that seemed to work ok for what i was doing
and yes the Tq rules
made a half round platten for the delta so i could lean in to it and not stall it as quick

not sure what the belt speed on the delta was but sept for hoggin it was too fast and too weak (too weak all around tho)
do i see two schools here
fast belt light touch
and slower belt with big lean
 
I don't have a heavy touch, though, Butch. I let the belt do the work, and I grind barehanded. Dip the blade almost every pass. I know of some guys grind the blade at a red heat (plain steels, not SS of course). Forged blades that need deep grinding to remove scale and dings.

If you taper tangs on a platen, though, it needs torque because of all that drag. Gotta hold it firmly on the platen so it stays flat. There I used a magnet. I went exclusively to stick tangs eventually to avoid tapering tangs.

I guess I'm of the turtle school that says "slow and steady wins the race". Even when I had only a single speed Bader I always used the slowest pulley. I just think there's a lot more control at slow speeds. Maybe it's partly because I was only rarely hurrying except at show time. I'm sure if it's one's living time is money and it puts a different spin on things.

We all develop our own grinding style. I just wanted to offer a different viewpoint.

Helluva nice tool, isn't it? I got mine in 2002 IIRC. Enjoy...
 
rfrink said:
hmmmm.... I have a few thoughts about this.

The VFD runs in a constant torque mode from 0 to 60hz...then it goes into a constant HP motor above 60hz (base speed of the motor).
Click to expand...

Any clue what the VFD setting for "constant torque" vs. "variable torque" would do? I noted it in the manual for Butch's VFD, but wasn't certain about the effect.

rfrink said:
If you run it at 120hz you double the motor speed....but since it is in a constant HP mode...you also cut the torque in half. If you are planning to do your heaviest hogging at this speed...you'll only have half of the torque.

A better solution would be to make run the motor near it's base speed (which is the peak HP and peak torque...@ approx 60hz). Use a different pulley ratio in between the motor and grinder to get the belt speed that you want. You'll be hogging at the highest belt speed and you'll want all the power and torque that you can get...which happens at 60hz.

So, if you want a belt speed of 5000ft/min ..then spin the drive shaft at about 5000 rpm. To do this with the 3500 rpm motor you need a pulley ratio of 3500/5000

which is the same 3.5 to 5.0 .....use a 5" pulley on the motor and a 3.5" pulley on the grinder.
Click to expand...

Certainly the pullies are the best way (I set mine up with pulleys. Though I may adjust the sizes after reading this. I'm running at 1:1 right now and overdriving things with the VFD.). I was thinking of the setup Butch has which is all on a custom made stand set up for direct drive. Of course, it looks like none of it will matter since he seems pretty happy with it as-is :)

rfrink said:
This is just the way that I would set it up....and I never argue with success.

I just love tinkering with machinery!!!
Click to expand...

Same here, and I have no problem listening to and learning from those with more experience than myself. Thanks for the insight Mr. Frink.

-d
 
You must log in or register to reply here.
Back
Top