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View Full Version : Midi Lathe Mods and set-up WIP



Ironwood
13th July 2014, 08:27 PM
Following on from this thread - http://www.woodworkforums.com/184586-midi-lathe-suggestions/ which helped me decide on which lathe I should buy.

About a month ago I bought a GPW Midi lathe, 6 speed model. I am in the process of modifying it to suit my needs, this includes building a bench/stand for it, and fitting a 1 hp 3 phase motor and a VFD to provide variable speed.

I don't get much spare time, so this has taken a lot longer than I would have hoped, almost a month to build this stand so far.

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I have used 50x50 RHS for the majority of the build, the motor bracket and supports are 50x50x6 angle. The whole thing is quite solid and very ridgid.

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I sourced some Vicmarc stepped pulleys, the one for the lathe spindle came with a 20mm bore, so it was a direct replacement which just needed a spacer turned up on the metal lathe to make the pulley sit in the correct spot so the belt cleared the casting.
The motor pulley came with a14mm bore, I had to bore it out to 19mm to suit the new motor. A local bearing supply shop supplied the belt to suit.

I have used the original belt tensioning bolt and lever on the new mounting plate, it will be accessed through a door at the front of the bench.

I am going to paint the frame with 2-pack polyurethane and fill the panels with sheets of form ply.

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gawdelpus
13th July 2014, 09:20 PM
Most Ideas take a bit more time to put into action than we would like ,that looks a substantial bit of gear indeed :) . What is the slowest effective speed of the motor as with that much power I probably would have used a single pulley drive and driven. With my woodfast midi variable it only has half that power but the pulleys are rarely changed ,not so much I am lazy,but the range I use is slow enough and fast enough for all that I do with pens :) . From CA finishes to buffing . It looks like you have to release the lever lock then lift the motor bracket relock it so you have 2 hands to change the belt ,then release the clamp drop the motor back down and relock it in position . Probably not too much of a hassle in the end :) All in all a worthwhile project . Cheers ~ John

Paul39
14th July 2014, 06:12 AM
Brad,

That is a wonderful stand, nice workmanship and positioning of the motor.

When you do your VFD control, consider putting it on a shielded cable with a magnet on the back so it can be positioned at the tail stock end.

If you start with out of balance bowl blanks, it is nice to not have to go past the flailing around blank to get to the E-Stop if things get out of hand.

My 20 inch swing old, old, variable speed Woodfast came with an E-Stop on a cord that has proven handy a time or two. I stick it to the right of the tail stock.The controls are mounted below the headstock.

Ironwood
14th July 2014, 08:20 AM
Most Ideas take a bit more time to put into action than we would like ,that looks a substantial bit of gear indeed :) . What is the slowest effective speed of the motor as with that much power I probably would have used a single pulley drive and driven. With my woodfast midi variable it only has half that power but the pulleys are rarely changed ,not so much I am lazy,but the range I use is slow enough and fast enough for all that I do with pens :) . From CA finishes to buffing . It looks like you have to release the lever lock then lift the motor bracket relock it so you have 2 hands to change the belt ,then release the clamp drop the motor back down and relock it in position . Probably not too much of a hassle in the end :) All in all a worthwhile project . Cheers ~ John

Hi John, if I ended up having to make some pulleys I would have gone with single speed, but as I got these pretty easily it saved me a lot of mucking around.

I dont envisage having to change the speeds at all, except for a rare occasion.

I wont know what the slowest useable speed is on the high speed pulley step until I get the VFD set up, but I am sure I will be able to spin it at less than 50 rpm, top speed will be somewhere between 3000 & 3500 rpm, depending on what I set it at.

Ironwood
14th July 2014, 08:27 AM
Brad,

That is a wonderful stand, nice workmanship and positioning of the motor.

When you do your VFD control, consider putting it on a shielded cable with a magnet on the back so it can be positioned at the tail stock end.

If you start with out of balance bowl blanks, it is nice to not have to go past the flailing around blank to get to the E-Stop if things get out of hand.

My 20 inch swing old, old, variable speed Woodfast came with an E-Stop on a cord that has proven handy a time or two. I stick it to the right of the tail stock.The controls are mounted below the headstock.

Thanks Paul. I plan to put all the controls at the tailstock end, I have all the switches and a pot. ready to go, just need the time to put it all together.

This lathe will be mostly used for penturning, so wont see many out of balance blanks, but I like to have the controls on my RHS anyway.

Penpal
14th July 2014, 12:07 PM
Hi Guys,

I applaud your new welded bench probably the most well made I have seen yet, can not comment on your choice of lathe (all the best anyway) but I recently bought a VL150 from Timberbits. I had a new VFD on my shelf as a standby for 5 yrs bought the VL150 bare lathe bench top model because I use for choice a sit down bench and the old VL100 it replaced was roughly the same size.

Lesson no 1 thousand as I was about to connect the VFD of the shelf I was advised by the maker to not use it until the capacitors were reformed as it could have blown up apparently after a yr or so the capacitors in these units general lose their capacity use requiring reforming. So I bought a new unit and also a new 2 hp motor to enable Delta connections on 3 phase rather than Star and my motors all were unable to change to Delta. The VFD I bought I elected to get the new model with the Variable Pot built into the front of the VFD (very convenient).

If it would be alright I can follow this posting with Pics of what I did or if its any help to others happy to start a new one.

My VL100 I have set up behind my operating position where it used to be to use in future for finishing my pens it has given sterling service for yonks with a different VFD.

Kind regards Peter.

Ironwood
14th July 2014, 06:29 PM
Hi Guys,

I applaud your new welded bench probably the most well made I have seen yet, can not comment on your choice of lathe (all the best anyway) but I recently bought a VL150 from Timberbits. I had a new VFD on my shelf as a standby for 5 yrs bought the VL150 bare lathe bench top model because I use for choice a sit down bench and the old VL100 it replaced was roughly the same size.

Lesson no 1 thousand as I was about to connect the VFD of the shelf I was advised by the maker to not use it until the capacitors were reformed as it could have blown up apparently after a yr or so the capacitors in these units general lose their capacity use requiring reforming. So I bought a new unit and also a new 2 hp motor to enable Delta connections on 3 phase rather than Star and my motors all were unable to change to Delta. The VFD I bought I elected to get the new model with the Variable Pot built into the front of the VFD (very convenient).
Peter, thanks for the tip on the capacitors if the VFD sits idle for too long, something to remember to run the machine now and then.

The VFD I have has the Pot on the front panel also, but I will also fit a remote pot and fwd/rev switch and Estop in a panel mounted beside the tailstock for convenience,


If it would be alright I can follow this posting with Pics of what I did or if its any help to others happy to start a new one.

My VL100 I have set up behind my operating position where it used to be to use in future for finishing my pens it has given sterling service for yonks with a different VFD.

Kind regards Peter.

I would be interested to see your set-up, as I am sure others would also.

Maybe better to start another thread though Peter, as I would like to keep this one as a log of my build.

Ironwood
14th July 2014, 06:36 PM
Not much progress today.
I mixed up a small pot of my 2 pack paint and brushed on a couple of coats on the bottom of the feet, so I can sit it on some blocks and spray the rest.
Hopefully will get it painted by the weekend.

I can't wait to get this thing set up and turning :-.

Ironwood
15th July 2014, 07:20 PM
Well I got the paint job done this afternoon.

I had planned on spraying it with the panels in place, but have taken the easy way out and just painted the metal frame.
The panels are made with new formply so they have that dark coating on them, should be sealed well. I will paint the edges to seal them before fitting them into the frame.

It will mean the bench will be two-tone, if I don't like it, I can paint it again before I fit the lathe to the bench.

I will probably make the front door and drawer fronts with timber, so it will end up having three colours.

Will have some more photos on the weekend when there is some progress to show.

Ironwood
26th July 2014, 08:06 PM
Well I have got it just about ready enough that it can be moved into position .
My lecky mate has already checked over the wiring and hooked up the 240v.

The form ply panels worked out OK, they are screwed and a bead of Sikaflex around the outside to seal the gaps.

Still have the door to make and the drawers as well.

I have mounted the controls under the tailstock, feels like a good position to have them.

I have set the ramp up speed at 3 seconds, ramp down at 2 seconds. The E-stop cuts power to the VFD, if I hit the stop , everything stops in 2 seconds, same as if I turn the fwd/rev knob to the stop position.
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I ended up putting the VFD in the compartment under the motor, I had planned to put 3 more drawers in there but went this way instead of mounting it externally.
The cavity on the RHS will have drawers.
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I put stainless security mesh panels in the sides and back for ventilation for the motor and VFD.
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I ended up running the cables on the outside, I wanted to have them run internally, but I would lose too much room for the drawers, so this is how it is.
If I had of planned a bit better earlier, maybe I could have drilled the 50mm RHS and run the cables inside the frame, but I think this will be OK.
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I replaced the fixed knob on the tailstock handwheel with a swivelling brass knob I turned on the metal lathe, much better.
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My handheld tacho had the batteries leak, it doesn't seem to work anymore so I can't check the speed range, but with a bit of rough calculation I am getting about 30 -3500 rpm on the high speed pulleys.
This will cover everything I want to do, and I always have the lower speeds if I need more low speed torque at some time.

I have cut some 3mm polycarbonate sheet for covers to stop the dust getting into the belt area under the headstock, they haven't been fitted yet.

DaveTTC
26th July 2014, 08:33 PM
very happy to have stumbled across this build ... nice work

Paul39
27th July 2014, 10:12 AM
Brad, Such a nice tidy installation. You do nice work.

Ironwood
27th July 2014, 12:10 PM
very happy to have stumbled across this build ... nice work


Brad, Such a nice tidy installation. You do nice work.

Thanks Paul and Dave. I am very happy with how the build has gone so far ( except for taking too long :rolleyes: )
I need to do a machine shuffle and run some ducting to fit it into the woodworking shed now.

oreos40
29th July 2014, 01:02 PM
Holy moly! thats a sweet setup!!