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KBC 830 Mill Tach Install

YotaBota

Mike
Premium Member
I finally got around to installing the lcd tach on my mill. Pretty straight forward and no surprises, I was able to drill the recess for the magnet without removing the pulley. I used JB Weld to hold the magnet in place.
Tach1.JPG

Next was make the bracket for the for the sensor, 1/8 alum, and position it under the magnet.
Tach2.JPG Tach4.JPG Tach5.JPG

The bracket for the display and the on/off switch (power) is also 1/8 alum, all the cutting and drilling was done on the mill. Then I mounted the bracket to the top of notepad board. All the wiring was bench tested to make sure it worked and the magnet would be mounted correctly. Success!

Tach6.JPG Tach7.JPG Tach8.JPG

My mill doesn't have a belt combination that gets in the 600rpm range, it was mentioned in another thread to try direct drive from the motor to the spindle, BINGO, I was able to get a 540rpm and a 650rpm which is perfect for a .500EM. The advantage to a link belt is being able to easily vary the length and it will do the minor bend around the middle pulley without flying off.

Tach9.JPG Tach10.JPG

Now if I do go to a VFD and 3Ph motor I'm ready for the speed changes. :)
 

curmudgeon

(Steve)
very nice Mike - I have a similar setup on my wood lathe, but my mounts are much more ghetto... I sacrificed an old cell phone charger to use instead of a battery, wiring it in parallel with the motor. There's a few seconds lag after the motor comes up to speed and the tach catches up.
 

YotaBota

Mike
Premium Member
Thanks Steve, I'm going to run thru the speeds and once I know what they are I won't need the tach until I go VFD. For $30 it's nice to know what speed the thing is actually turning at.
 

curmudgeon

(Steve)
The Shopsmith has continuously variable speeds provided by a sheave assembly that operates similar to a Reeves pulley. At the time, it seemed very important to know how fast the spindle was turning, even though my edition of the Machinery's Handbook doesn't have SFM charts for turning arbutus and Gary oak. Now, I rarely glance at the tach display and just go by feel.
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Thanks Steve, I'm going to run thru the speeds and once I know what they are I won't need the tach until I go VFD. For $30 it's nice to know what speed the thing is actually turning at.

I'd have one of those in a heart beat over the chart I'm using. Instant speed check plus confirmation.

What are the chances that a glued on magnet will stick at 4000 rpm? Basically, I'd love to do this now but I think I have to wait till I have my head apart so I can get at something on the spindle.
 

YotaBota

Mike
Premium Member
What size link belt are you using?
The belt is the smaller 3L(3/8") size, it should the 4L(1/2") but the 3L is what I had and it works okay.

What are the chances that a glued on magnet will stick at 4000 rpm?
If the magnet is recessed and glued it should stay there at 4000rpm with no issue. It's not far off center and doesn't weigh much so there won't be a ton of centrifugal force trying to toss it away.

operates similar to a Reeves pulley
There is a Reeves setup for sale on used.ca Victoria that I was looking at for my bandsaw. I wonder if they're any good?
 

DavidR8

Scrap maker
Administrator
Moderator
Premium Member
There is a Reeves setup for sale on used.ca Victoria that I was looking at for my bandsaw. I wonder if they're any good?
Reeves drives were commonplace in wood lathes to give variable speed. Some like them, most hated them because they were noisy and somewhat fragile. Parts are used die cast aluminum alloy or worse and in 100% of the cases I've read about no longer available.

If I were going to convert a bandsaw to variable speed. I'd do something like this:
 

curmudgeon

(Steve)
What are the chances that a glued on magnet will stick at 4000 rpm?

Empirical testing has confirmed that hot glue will not hold a magnet to a treadmill motor flywheel. I wonder what 25'th century archeologists will think when they find the magnet in the ruins of my shop?
There is a Reeves setup for sale on used.ca Victoria that I was looking at for my bandsaw. I wonder if they're any good?

I contemplated buying that unit for the components. The Reeves Junior pulley included is rated for 1/4 to 1 1/2 HP use. It looks like that unit is well designed and keeps the motor shaft parallel with the drive shaft as the speed is changed.

The Shopsmith implementation is pretty cool. The motor has a fixed mount, with a belt to the "speed changer", and another belt to the machine spindle. As the speed changer is rotated around a mounting pin, a floating sheave slides on the jack shaft, increasing/decreasing the relative diameters of the pulleys for the motor and machine belts.
spdchg-005.jpg

With my current setup I get a range of 550-2230 RPM which suits my needs pretty well.
147652728_10158791900655491_5938684397878270221_n.jpg
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Mine will go into a Hartford Bridgeport Clone with a radius of around 3" on a 6" pulley. It's unlikely to ever see 4000 but with the VFD, it is possible to hit 4500 at 120 Hz.

I had hoped to install it on the spindle itself the next time I have the head apart. But that could be 20 years from now. It's very appealing to try something like epoxy on the pulley for now.

No 25'th century archaeologists will be exploring my shop. Maybe a team of anthropologists will wonder about the triple stranded DNA with fur on it and stone tools though...
 

DavidR8

Scrap maker
Administrator
Moderator
Premium Member
I am mildly sensitve to epoxy so I tend to use red Loctite (the one you have to heat to separate) to glue metal to metal and never had a failure.
 
Last edited:
Mine will go into a Hartford Bridgeport Clone with a radius of around 3" on a 6" pulley. It's unlikely to ever see 4000 but with the VFD, it is possible to hit 4500 at 120 Hz.

I had hoped to install it on the spindle itself the next time I have the head apart. But that could be 20 years from now. It's very appealing to try something like epoxy on the pulley for now.

No 25'th century archaeologists will be exploring my shop. Maybe a team of anthropologists will wonder about the triple stranded DNA with fur on it and stone tools though...

I found some old footage, a brother perhaps?;)
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
I found some old footage, a brother perhaps?;)

That's hilarious!

Could be a younger brother from another mother.... Right down to the Sas his bride calls him! I get that a lot and sometimes even shorten it myself that way!

My own fur is all snow white now. Been getting Yeti lately......
 
That's hilarious!

Could be a younger brother from another mother.... Right down to the Sas his bride calls him! I get that a lot and sometimes even shorten it myself that way!

My own fur is all snow white now. Been getting Yeti lately......
....... Well, I did find some more recent footage as well...... Just figured you were being elusive....

 
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