DIY powerfeed

[Hilltop366]

Instead of a limit switch on both ends and all the wiring to go with it could you just put one switch on the mill head and  bumpers on the mill frame to activate the limit switch? The far end bumper could be magnetic so you could easily move it. 

[fluidpowerpro]

Thats is how mine is. The other 2 limit switches are for "obstruction protection" If the mill hits an obstruction my idler sprockets swivel and trip a switch. One switch is needed for each direction of travel. If you scroll down in this thread you will see pictures showing how it works.

[Hilltop366]

I was thinking that if it had a rod that went from front to back horizontally on the saw head frame with a couple of bumps on each side of the switch and compression springs on each end to return it to centred position.

When the rod hits the bumper on either end it would slide horizontally and one of the bumps would open the switch stopping the feed power.

The next thing it would need is a way to bypass the kill switch to start the carriage travel again, either a momentary bypass switch to press for a second until the kill switch is returned to centre or a way to move the rod or switch for a second so the bump is not activating the switch.

My thinking is the less switches and wires the less trouble down the road.

[never finished]

 Yes it will have a bypass for each switch and the switches will be on the saw with the reverse bump stationary and the forward bump moveable. I saw a lot more 8' and 12' logs than 20'. I also want to put one on the far side of the saw for the always hiding dogs. Yep I still hit them after all these years. But only with new blades. And again thanks for the help.    

[mroldstyle]

You don't really need a bypass, just run the head in opposite direction of what just tripped the switch.

[fluidpowerpro]

It likely depends on your circuit. On my set up I found that I did need a by-pass switch. I just used a momentary push button that I hold until the saw moves off of the limit. 

[fluidpowerpro]

@ never finished.
I will be anxious to see what you come up with to sense dog height vs blade height. 
When pushing the mill by hand I would quickly get a audible warning that I hit the dog and I could stop before doing too much damage. That wont be the case using power feed so having some sort of safety device is a great interest to me. 

[never finished]

We'll I was kind of thinking just mentioning it would get you started since we have the same mill. I'm thinking a paddle that hangs down out in front of the blade guide and over far enough to hit the squaring dogs. about 1/2" below the blade height. Paddle swings back into switch. That will even catch those knots that stick out far enough to get past our extensions on our dogs. OK Tom I've got you started run with it.       

[fluidpowerpro]

Ya, you got me thinkin......

[fluidpowerpro]

Finally used my saw the last few days. The power feed works great and the overload mechanism works perfectly.  
I love it and wish I would have installed it a long time ago. Its really going to be nice not coming home dead tired after sawing all day. 

[never finished]

I'm back. I got mine going a week or so ago, works great. I am positive I will need switches to stop it from hitting end of track. I am so used to operating it with the wheel chair controls that I am plum dangerous with this set up. But I like it. It's just going to take my old brain some time to adjust   . What I"M thinking is if I go through the forward-reverse switch to toggle switches with some rubber tubbing slid over the end of them for some give in the switch when it hits the stop block out past the actual switch it should stop without breaking the switch. The forward-reverse switch will  act as the bypass switch. Just switch it and go the other way. But before that I have parts ordered to use an actuator on my throttle. I'm tired of having to reach over and holding the throttle on full blast. Still waiting on Tom to figure out hitting the dog switch.            

[fluidpowerpro]

The dog switch is a great idea but my challenge would be that I have 2 dog locations on my mill. 
One set is located at the max width and another set is 6" in from max. 
The switch would need to mount on the exit side guide block so it would work on the max width backstops but it wouldn't on the ones located farther in.
I guess you will need to take the lead on that one. 

[never finished]

 The only dog I'm concerned with is the squaring dog on other side of the track from me. Even though I have a gauge on my side I still hit it just often enough to make  feel not so smart. what about the idea of going through the forward-reverse for the  momentary stops. does that make any sense or am I missing something. AS fast as the travel stops when switching off I don't think much forgiveness is going to be needed on the momentary switches. What kind of momentary switch works for momentary off?    

[jpassardi]

NF: Yes that does work, I wired mine that way.
The forward limit switch (normally closed) is in series with the forward leg of the toggle switch. When it hits the end of forward travel it opens the circuit and stops the feed motor. You then switch to reverse, once you move back a couple inches  - enough to "untrip" the limit switch it's again able to go forward for the next pass.
The same wiring is set up in reverse and same operation as forward.
Very simple, works well. I have mine tied into a cheap PWM for variable speed, same with the up/down gear motor. - Photos earlier in this thread.

[never finished]

Thanks jpassardi. One of the problems I was having is I was not including the word limit, with momentary which was giving me problems in finding the correct switches. (  ) Now that you have me strait on the wiring I might possibly get it kind of right.    

[mroldstyle]

Thats how I wired mine in also. Works good

[jpassardi]

 Happy to help. Variable power feed and up/down were definitely worthwhile upgrades for me and not expensive.
Now I just need find time to finish my 2 plane clamp and toe board!

[never finished]

 I did the pineywoods turner-clamp years ago and it's great. I have had the power feed with the whole wheelchair set up for quite a while. I would have just stuck with that but I was having a few little problems with it and started to worry about what  it would cost for parts. If you havn't done it yet. I think the laser on the scale improved the quality of lumber more than any mod I"ve done. What would we have done without this forum. If I was  still sawing it would be much harder.