Re: Variable speed

[DougLA]

Tool fan,

Looks good and no doubt a fun project. My opinion would be if you want some idea of rpms - it's there.

I have a 10,000 watt SCR on the way from Amazon. Hope to gear up with a treadmill motor on my Beaver 3400 as a 2nd lathe or perhaps a bandsaw. Looking forward to messing around with it and answering question as to how many DC volts this controller puts out.

Doug

[tool fan]

Tool fan,

Looks good and no doubt a fun project. My opinion would be if you want some idea of rpms - it's there.

I have a 10,000 watt SCR on the way from Amazon. Hope to gear up with a treadmill motor on my Beaver 3400 as a 2nd lathe or perhaps a bandsaw. Looking forward to messing around with it and answering question as to how many DC volts this controller puts out.

Doug

Thanks Doug, It was fun and I think I should have kept the heart monitor hardware so I can measure that while I use the lathe.

I sure hope the 10,000 watt SCR works. Free treadmills are becoming a scarcity around here. About a year ago I could pick one up whenever I needed one. Now, they are gone within a couple of hours of posting. Right now I have loads of the little motors but no controllers that can deliver enough power to be effective. Keep us informed when you try the one you ordered.

[DougLA]

tool fan & Braz-in-the-Peg,

I've set up one of the 10,000 watt SCR's as a self contained controller in a recycled 4X6X6" PVC junction box and incorporated a voltage meter and reverse polarity DPDT switch. Same regulator as Braz-in-the-Peg a few posts back. (10000W AC110V 220V 75A SCR Voltage Regulator Speed Controller via eBay) As he said maximum voltage he calculated does appear to be 130 volts at least on motors I tried it on. Not sure what I will do with it - if nothing else, useful to have a variable DC voltage power supply. Must say it is not as "smart" a controller as treadmill MC-60 or KB electronics controller that I am presently using on my lathe - as it does not have any voltage or current compensation when under load. Guess would be OK with a smaller lathe and I'll likely rig it up with my old Beaver 3400 I have on a shelf.

Just threw together a Flickr album:
https://www.flickr.com/photos/767624...57714856974796

[tool fan]

I like the setup, very tidy and I like how you have incorporated a voltmeter. I f you find that it produces enough torque at low speed for your Beaver lathe I will be copying you. Thanks for sharing the details.


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[DougLA]

Thanks Rory.

Out of interest I had tried this controller with my lathe which uses same model treadmill motor as in last post and is set up with a KB Electronics controller. I have been roughing out wet beech into 16" bowl blanks and it was easy enough to temporarily wire in new SCR controller.

Comparing the two, my present set up does work hard turning these large items but is quite satisfactory. Using the new SCR controller it is much easier to stall, I presume as no voltage or current compensation under load. I'll see how it works doing lighter, smaller stuff either again temporarily wiring it back in to present lathe or set up with my unused Beaver 3400. Might be after the summer before get a roundtoit. As per Braz-in-the-Peg I guess it will be fine with smaller items.

Doug

[tool fan]

Wow that's quite a large bowl!   Your experience with the SCR controller is what I remember.   My conclusion was that it was about the same as the already packaged DC 51.  

Here's my latest project.   I actually found two of these old Rockwell lathes with what look like original Preston Leland  3/4 HP 3 phase motors.  

 

[DougLA]

Nice!

[tool fan]

Here's a new one for me. It's a wood bandsaw adapted for metal. To slow the blade down, a little 2 speed transmission has been connected to the motor. It has 2 speeds Slow and very slow.

[Leo Van Der Loo]

Quite the setup on that one Rory, must be having lots of power going to the band.

I added a slow speed to my 4 speed 14" bandsaw that was still way to fast for cutting metal/steel, so I added a jackshaft on the backside to reduce the speed for cutting hard steel, Cooper/brass and aluminium, works fine, though I seldom made use of it.

I build a cover that is hooked over the outboard motor, keeps it safe and the sawdust off.




The loose belt in the picture is hooked onto the saws motor and the outboard motor is then doing the metal sawing, I calculated that a 1/10th of a HP would be able to do that, and I had one from a garage door opener that I scrapped, but it had no easy to bold down foot, so I went with this bit large motor, the large pulley was from that opener IIRC, anyway the 4 wood cutting speeds are on the RH side of the wheel cover and the metal cutting speeds on the LH, no variable speed but it works.

[tool fan]

I like your setup Leo. It gives you lots of flexibility.

Mine will be strictly for metal. There’s a lot of power with this arrangement. The guy that made it was a machinist and it was clear that he had cut 1/2” steel plate with it. His daughter inherited this bandsaw, a General 250 tablesaw, a big Colchester metal lathe and a lot of hand tools. I got the bandsaw and the tablesaw. Both were well used and grimy but in good condition. I cleaned up and sold the tablesaw and haven’t decided what to do with the bandsaw. The wheel tilt mechanism is cheap and the hinge is cracked. I’m going to make a new hinge and then decide what to do with it.


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[Leo Van Der Loo]

I made this simple ad-on, the wheels clear the floor by 1mm or so, I tilt the saw forward and can then move the saw around easily, just have to keep the saw balanced when moving

[al.m.. [OP]]

Amazed this thread is still going,no doubt the longest living thread I ever started.kinda ironic,today I sold the lathe that inspired this topic to a new member here, Brad.I included a spare motor,control board and transformer,perhaps he can learn and improve a already solid system

[DougLA]

Here's my version of a variable speed bandsaw, I recently reno'd. It is the 3 speed King KC1433FX acquired recently via Kijiji for a good price.. Speed range now from zero to 3200 fpm. In lowest gear the lowest useable speed is ~ 200 fpm and I intend to use for cutting metal. Just got a metal cutting blade and will report back as to how it works. Have since also added a 6" riser block.

video: https://www.flickr.com/photos/767624...7716915721373/
album: https://www.flickr.com/photos/767624...57716915721373

[tool fan]

That's nice work you've done there Doug. That looks like the same motor that you put on your Craftsmaster with the KB electronics control board. Did you find another motor? Also, it looks like you are using an MC 60 board on the drill press. Do you step it up to get to 240 volts?

[DougLA]

Thanks Rory. The fellow I purchased these DC treadmill motors from had 3 and I took all of them. (He actually threw the third one in for free.) The same motor I used on lathe is plugged into a 30 amp 220 circuit and set up to run with KBMD controller at 180 volts for a top motor speed of ~3600 rpms.

In the case of the bandsaw as above with the same model motor I used an MC64 plugged into 110v wall current and at top speed with the R37 resistor clipped (thereby increasing IR compensation) it put out somewhere around a max of around 100 volts giving motor rpms of ~1900 rpms.

However at top speed there did seem to be some motor cogging with the MC64 and since then I've actually found an older style treadmill with a Sabina controller that puts out a cont. rating of 12 amps up to a peak of 20 amps. It also has max speed and IR compensation trim pots and and set to max it puts out about 120volts and purrs along without cogging for a max motor speed of ~ 2200rpms. On a 15 amp circuit it will sometimes trip the wall breaker on start up, but no problem what so ever on a 20 amp 110 circuit. For some reason the motor runs extremely quiet with this controller and at low speed it is difficult to tell its even on!

I need to update the Flickr album. Here's some pics.