Thread: New Lathe Part 2

On another subject, has anyone tried or thought about trying a multiturn potentiometer with a counting dial to provide the speed control for the VFD?

Multiturn Pot and Dial.jpg

This is a 10 turn Pot. I don't think 10 turns are required but this is what I have found so far.

http://www.ebay.com.au/itm/10K-Ohm-3...item19d6429d2f

$6.38 delivered. 10 turns at 100 grads per turn gives 1000 grads over the full range of the pot.

Dean

Originally Posted by Oldneweng

On another subject, has anyone tried or thought about trying a multiturn potentiometer with a counting dial to provide the speed control for the VFD?

I've thought of using one to control the speed from the cross slide to give constant surface speed when facing. You know the old radio tuners with the string wrapped around a wheel? That kind of thing. You could use the wheel size to fine tune the rate of change.

As a main (manual) speed controller, not sure I see the advantage of the multiturn pot.

lol, you must have caught me mid edit. I left your arm out

Yes folding down, that way you cant loose the possums cant move it. Not that something like that would ever happen in my shed.

As for pots. Yes.... Me. I have pots with a little clock in the front. Set up so you have 5 turns of forward and 5 turns of reverse......none of this messy switch business
You can see the effect but not the pot on the video in this post.
The clicking you can hear is just the brake coming on when I adjust the freq to fast. I have it set up with the VSD if "off freq" the brake on the hoist comes on.

https://www.woodworkforums.com/showth...76#post1569076

Stuart

Like this.

http://www.ebay.com.au/itm/20mm-10K-...1d92fd1&_uhb=1

Originally Posted by Stustoys

lol, you must have caught me mid edit. I left your arm out

Yes folding down, that way you cant loose the possums cant move it. Not that something like that would ever happen in my shed.

As for pots. Yes.... Me. I have pots with a little clock in the front. Set up so you have 5 turns of forward and 5 turns of reverse......none of this messy switch business
You can see the effect but not the pot on the video in this post.
The clicking you can hear is just the brake coming on when I adjust the freq to fast. I have it set up with the VSD if "off freq" the brake on the hoist comes on.

https://www.woodworkforums.com/showth...76#post1569076

Stuart

So that explains it. I have seen strange things before. I am not sure how to get the thumbnails showing at the bottom of the post (not that I actually want to) as well as the pictures, but one day I was finding it difficult to load pictures, selected the wrong one, replaced it with the right one and all was good. Except that although the pictures in the post were correct, the thunbnails still had the wrong picture instead of the replacement one. I seem to recall this happening with other peoples posts as well. Sometimes I think that the speeling gets changed along the way too.

I have to foil those pesky creatures somehow. I am working towards having everything inside cupboards. Then they won't be able to knock things over, and I will have to find another culprit!

That pot is different. I have not seen one like that before. It is more expensive tho.

174 Meg video? I am going to have to leave that one.

Dean

Originally Posted by Bryan

I've thought of using one to control the speed from the cross slide to give constant surface speed when facing. You know the old radio tuners with the string wrapped around a wheel? That kind of thing. You could use the wheel size to fine tune the rate of change. ....

Bryan, if you develop that idea, keep me (or the forum) informed of your deliberations and design options. I've been thinking about an adjustable radius dependent speed control system for my lathe. I was thinking along the line of a processor controlled setup using my spindle tacho and my linear scale somehow - and that's where I get lost....
Your idea is a mechanical system that I understand easily.
A bit of thinking involved in pre-setting the starting speed or the final speed, then it doesn't seem so far fetched!
I'd be considering something along the line of a spring loaded fine wire rope (like the gear change bowden cable off a pushbike) over a pulley on the pot - which is tucked out of harms way. Making that pulley adjustable could then change the rate. I'have to think where to wire this pot in in relation to the normal one since the VFD is only respondeing to the resulting voltage.
Great new food for thought!

Originally Posted by Stustoys

...I have pots with a little clock in the front. Set up so you have 5 turns of forward and 5 turns of reverse......none of this messy switch business ...
Stuart

Stuart, that might be a way around the other issue we;ve been discussing: How to set two ramp profiles (for deceleration - operational and emergency stops) without running out of multi-purpose terminals on the VFD, while maintaining directional control AND jogging control....

FOr everyone else's benefit: when I have found a solution (with others' help!) I'll post what we are working towards and the solution. Still some trial and error and testing to go.....

Originally Posted by jhovel

Bryan, if you develop that idea, keep me (or the forum) informed of your deliberations and design options. I've been thinking about an adjustable radius dependent speed control system for my lathe. I was thinking along the line of a processor controlled setup using my spindle tacho and my linear scale somehow - and that's where I get lost....

How about just using a straight pot (that is, a straight line action) with a slider that is coupled to the cross slide? Even wind or make your own. I have plenty of nichrome wire if someone wants to experiment.

Michael

Originally Posted by jhovel

Bryan, if you develop that idea, keep me (or the forum) informed

Will do Joe, but don't hold your breath, it's a long way down my list since the lathe with the VFD is not fully functional and not in use. And I can't even find any shed time for the things that are high on the list! So I'd be happy if someone else would pick up the idea and develop it.

Originally Posted by Michael G

How about just using a straight pot (that is, a straight line action) with a slider that is coupled to the cross slide? Even wind or make your own. I have plenty of nichrome wire if someone wants to experiment.
Michael

Mmmm - intersting idea Michael! I kind of liked the idea of a rotary pot for the easy way you can get it out of the way of chips.... BUT that is an option I hadn't considered seriously..... will do so now.

Originally Posted by Oldneweng

I am not sure how to get the thumbnails showing at the bottom of the post (not that I actually want to)

I like the thumbnails, at least when I am mobile.

Originally Posted by Oldneweng

174 Meg video? I am going to have to leave that one.

I cant see the size, but this like might be smaller(Might not to. You have the idea anyway)

https://www.youtube.com/watch?v=7RLh0VMnfeg

Originally Posted by jhovel

I'd be considering something along the line of

How about you extended the cross slide screw(or maybe a flexible shaft), put a little gear on the end 10:1 onto a gear on the pot. That will do up to 400mm.(if your screw is 2mm pitch)
I'm pretty sure there would be a lot of tweaks you could make with the settings on the VSD.

Originally Posted by jhovel

Stuart, that might be a way around the other issue we;ve been discussing: How to set two ramp profiles (for deceleration - operational and emergency stops) without running out of multi-purpose terminals on the VFD, while maintaining directional control AND jogging control....

Maybe. but I'm not sure there is a "off" position in the center........ but as I say there are a lot of tweaks you can make with drive settings and for the hoist off in the center is something I didnt want so didnt look.
It is on my list of ideas for a making another lathe work with the look and feel of factory yet being on a vsd. (you can just throw the thing from fwd to res and high to low speed)

Stuart

Originally Posted by Bryan

I've thought of using one to control the speed from the cross slide to give constant surface speed when facing. You know the old radio tuners with the string wrapped around a wheel? That kind of thing. You could use the wheel size to fine tune the rate of change.

As a main (manual) speed controller, not sure I see the advantage of the multiturn pot.

Bryan I was just thinking of having a bit more accuracy. I don't want 10 turns by any means, but If I make up a chart of speed against grads on the pot, it will be easy to dial in whatever speed is required. At the moment the pot on my lathe is very sensitive as it has a lot of rpm variation to cover. Dial in speed control.

This seems to have sparked some interest. I hope it does not finish up like the last time I sparked some interest ROFL.

Dean

I like the thumbnails, at least when I am mobile.

Stuart, the thumbnails I was talking about were the ones that show up at the bottom of the post, when the actual pictures or thumbnails of pictures are positioned further up. In this case there are 2 of each picture in the post. This does not normally happen with my posts. These thumbnails are highlighted and have something like "Thumbnails of Pictures" inserted by the forum application.

I like thumbnails period, because then I can choose which pictures to view at full size. The pictures (Thumbnails) in my post were correct, but the thumbnails at the bottom (which don't normally appear in my posts) still had the wrong picture in it. Maybe these thumbnails appear when a change is made with the pictures. Maybe I haven't got a clue. BobL's thread about his work in the playground, in the Small Timber Milling sub forum has thumbnails at the bottom of the post.

Moving on.

I managed to acheive something today, I think.

I fitted the JVC car stereo from our ute, into a car belonging to a friend of my wife. This stereo was replaced with a top of the range, although old JVC unit some time ago. The better unit came out of my old car. The cheap one could only play commercial CD's. The other one can play almost anything including DVD's. Anyway, in return for this, my wife and her friend dug out the hole for my lathe slab. They did a good job. A bit of tidying up, a couple of form boards, and organising a way to level the surface of the concrete and I can start pouring. I wonder how long it will take me. Got to do it in one go. The surface will be lower than the concrete at each side due to movement over the years.

Dean

Dean that sounds like a fair trade. For the pour you'll need a mixer and preferably a mate.
I'd offer but I've got no time, at least not for a few weeks.