Planning power feed

rrleesb · February 03, 2018, 09:26:19 AM

I'm planning my power feed on my 4 post mill. My plan is to run 2 #50 chains down each rail. I'll run the chain up the carriage past two idlers between the two uprights to a shaft that drives both sides. Then drive the shaft with a 24v wheelchair motor. I have 13 tooth sprockets for my driveshaft. Will a 20 tooth sprocket on the wheelchair motor provide a decent feed rate? I do have two pwm units I'm planning on wiring up.

Kbeitz · February 03, 2018, 09:48:29 AM

Why two chains ?

rrleesb · February 03, 2018, 10:17:09 AM

I read that people liked both sides and it wasn't too much more to just do it for both sides. Cooks does both sides so there must be a reason for it. If I decide to do a board return at some point I'm sure that I am going to be glad that I did both sides.

Kbeitz, I did get the 24v/10A relays for wiring the PWMs up to the forward/reverse through a 3pdt switch.

Kbeitz · February 03, 2018, 11:38:58 AM

Quote from: rrleesb on February 03, 2018, 10:17:09 AM
I read that people liked both sides and it wasn't too much more to just do it for both sides. Cooks does both sides so there must be a reason for it. If I decide to do a board return at some point I'm sure that I am going to be glad that I did both sides.

Kbeitz, I did get the 24v/10A relays for wiring the PWMs up to the forward/reverse through a 3pdt switch.

The relays are cheap off E-bay. You might as well add safety stop limit
switches to your carriage to. This way you can send the mill on it's way
and walk somewhere to do something else with out worry. It will also
keep you from wringing a shaft off if it doesn't stop for some reason.

DPatton · February 03, 2018, 11:49:36 AM

Quote from: rrleesb on February 03, 2018, 10:17:09 AM
I read that people liked both sides and it wasn't too much more to just do it for both sides. Cooks does both sides so there must be a reason for it. If I decide to do a board return at some point I'm sure that I am going to be glad that I did both sides.

TimberKing does chains on both sides as well.

york · February 03, 2018, 12:18:15 PM

Well,if your thinking about someday,board return.....Ya better be thinking about Hydraulics....

Hilltop366 · February 03, 2018, 12:30:26 PM

Quote from: rrleesb on February 03, 2018, 09:26:19 AM
I have 13 tooth sprockets for my driveshaft. Will a 20 tooth sprocket on the wheelchair motor provide a decent feed rate?

Sounds backwards to me, I would have thought you would want to gear it down (small sprocket on motor and large sprocket on driven shaft) so you can use the upper end of the motor speed to increase torque.

Den-Den · February 03, 2018, 03:25:13 PM

I don't know the speed / torque specs of wheel chair motors so can't comment on how they should be geared.
My home built mill uses # 40 chain on one side only, two sides may not be needed but can't hurt.

Kbeitz · February 03, 2018, 03:29:27 PM

I also think that you'r going to need to go with a small sprocket
on the gear motor and bigger on the driven side.

Kwill · February 03, 2018, 09:15:07 PM

I'm scratching my head trying to figure out how this works.

Kbeitz · February 03, 2018, 09:41:14 PM

It's like pulling on a rope. If you pull hard enough you will pull your self along.

Kwill · February 03, 2018, 09:44:25 PM

Quote from: Kbeitz on February 03, 2018, 09:41:14 PM
It's like pulling on a rope. If you pull hard enough you will pull your self along.

I guess I need to get my eyes checked. When I first looked at the picture I could have swore the chain ended. Like a short foot piece of chain. But I'm assuming it runs the length of the saw bed

Kbeitz · February 03, 2018, 09:57:32 PM

Looks like the chain goes under a sawdust deflector.

Ianab · February 03, 2018, 10:49:31 PM

Yup. The other end of the chain will be bolted to the other end of the mill, like the end we can see. The bolt on the end of the chain lets you remove any slack from the chain.

My swing blade mill has a similar mechanism to move the head from side to side. Chain is fixed and runs the width of the mill carriage. There is a hand crank where the motor is in that picture, turning the gear on the chain. Chain can't move, so the cog and hence whole carriage will move down the chain.

starmac · February 03, 2018, 10:54:09 PM

The picture is decieving, at first glance it looks like the sproket can only move a few inches, when reality the cover over the chain is moving with it, just there to try and keep the sawdust off the chain.

Kwill · February 03, 2018, 11:15:41 PM

Quote from: starmac on February 03, 2018, 10:54:09 PM
The picture is decieving, at first glance it looks like the sproket can only move a few inches, when reality the cover over the chain is moving with it, just there to try and keep the sawdust off the chain.

yeah that's what threw me

Kwill · February 03, 2018, 11:30:25 PM

That's a pretty good size motor on that one. Wonder if its 110?

starmac · February 03, 2018, 11:43:42 PM

Kbeitze. I like the idea of your stop switch, but have a question.
When it hits the switch, does it come to a sudden stop , or does it kill the power and let it coast to a stop?

Kbeitz · February 03, 2018, 11:56:52 PM

The stop is spring loaded to cushion the stop. Since you bought relays you can
just wire the limit switch in series with the relay. One relay for each direction.
The switch will shut down only one relay so you can still move the other way.

Kbeitz · February 04, 2018, 12:00:19 AM

Quote from: Kwill on February 03, 2018, 11:30:25 PM
That's a pretty good size motor on that one. Wonder if its 110?

I have some Dayton DC motors that look like that.

kelLOGg · February 04, 2018, 06:43:49 AM

When I planned my single side chain drive to my MP32, Cooks advised me to build it so 2nd chain could easily be added. When sawing a large oak I noticed the non-driven side would play "catch up" leaving a rough cut. I assumed this was due to slight lateral play in the rail rollers. Adding the 2nd chain immediately cleared this up. Interestingly, I noticed in Cooks later models of the MP32 (mine is 16 yo now) they used only 1 chain. Maybe the newer rollers have near zero lateral pay. Anyway, wear happens and I think you are wise and safer using a 2 chain drive.

kelLOGg · February 04, 2018, 06:52:54 AM

Kwill,
Your mill looks like the MP32. Are you building a clone? You're doing a great job.
Bob

Kwill · February 04, 2018, 11:37:50 AM

Quote from: kelLOGg on February 04, 2018, 06:52:54 AM
Kwill,
Your mill looks like the MP32. Are you building a clone? You're doing a great job.
Bob

that's not my mill

rrleesb · February 04, 2018, 04:01:26 PM

Quote from: Kbeitz on February 03, 2018, 11:56:52 PM
The stop is spring loaded to cushion the stop. Since you bought relays you can
just wire the limit switch in series with the relay. One relay for each direction.
The switch will shut down only one relay so you can still move the other way.

I really like the idea of the limit switches. What did you use? How long is your spring?

starmac · February 04, 2018, 04:28:12 PM

Another question about the limit switches,
Do they reset themselves, or do you have to manually have to reset them?
Another thing is, how much does a guy really use them, my mill can cut a 21 foot log, but I probably cut more 8 1/2 footers by far than maximum length, so realistically do not let it travel to the end much.
On the return, the way mine is currently set up, it has to be right against the stop for the hydraulics to work, which requires me to manually stop it, or it will bounce back just enough to not engage the power strip. I do plan on eventually lengthening my power strip because this is a royal pain, having to have it right against the stop.