My new lathe a Warco 918

[Ron LadenParticipant @ronladen17547]

Made up a mount for the cross slide control and added a small enclosure, seems the obvious place for the control. This will have an on/off, fwd/rev and a speed/feed control. Just waiting on components to finalise the wiring.

[Ron LadenParticipant @ronladen17547]

I finally got the electrical parts together to allow me to wire the cross feed drive and get it finished off. I mounted the end stop micro switches onto a thin walled piece of alu angle which also serves as a swarf guard. I fitted the mount to the r/h side of the saddle with a couple of 4mm spacers to stand it off the slide. I also milled a slot in the mount to allow the switch activation pin to protrude through, the pin is a piece of M3 studding which is screwed into the side of the slide. The mount covers access to the slide gib adjusting screws but should I need to make any adjustments just 2 screws and the mount is removed. Overall travel front to rear of the slide is 85mm which I think will be fine, a couple of pics below.

Edited By Ron Laden on 23/07/2020 15:10:35

Edited By Ron Laden on 23/07/2020 15:14:19

[Ron LadenParticipant @ronladen17547]

Tis finished, the cross slide drive is all wired and working well, really pleased with it how it turned out and good fun to do. I think I mentioned before that I have gone with the easy option, as you can see in the video below the motor/gearbox/dog clutch sit a fair way back but I am ok with that. I dont have a rear splash guard so I could get away with it, the lathe didnt come with guard so I just use pieces of heavy cardboard or whatever and change when needed.

With a rear guard there are a couple of options, you could cut a horizontal slot in the guard just enough to allow the motor to pass through. Other than that the motor/clutch would have to be lowered to beneath the rear of the cross slide and brought forward but that would get more complicated as it would need a belt or gear drive up to the leadscrew. I did consider a drive on the front of the saddle but it would be seriously complicated and need some major surgery and as much as I wanted a cross drive I didnt want to go that far.

The variable speed I think is a nice feature from dead slow to quite fast, too fast at the top end for cutting but good for bringing the tool back from a cut which on larger work could be quite handy. The torque from the motor/gearbox is quite impressive considering they are not that big a unit, thats why the end limit switches are a must as an over-run could do some damage.

Cost wise about £75 in total for the motor/box, speed controller, DC power supply, switches/electrical bits, I think that comes out as pretty cheap in adding a driven crossfeed from scratch to a lathe without one. So for any 920 owners if you fancy a driven cross slide it is doable and I,m sure there are more ways to skin a cat this was just my approach.

[Ron LadenParticipant @ronladen17547]

I forgot to say there is one job left to do and that is to add a support bearing to the rear end of the leadscrew, it will need a pocket milling in the leadscrew channel to accept a mounted ballrace. The end of the leadscrew is unsupported rear of the nut and it doesnt run dead true which is not normally a problem you would never know but connected to the clutch which has some clearance between the parts it creates a bit of out of true running. It works fine but would be better centered and supported in a bearing.

Ron

Edited By Ron Laden on 26/07/2020 20:20:33

[Ron LadenParticipant @ronladen17547]

I thought I had better test the drive with a heavyish load to check for any problems so took a 100 thou face cut in steel (spec unknown). No problems at all, not a hint of hesitation so pleased with that, you can see the fast retrieve from the variable drive which is quite handy.

[Niels AbildgaardParticipant @nielsabildgaard33719]

Very nice video.

Next must be a parting off video.

That is where wheat and chaff are sorted.

Can we have some newer information on ideal motor torque,rpm and gearing?

I want it on both axes.

Thank You for experimenting and finding the way.

[Ron LadenParticipant @ronladen17547]

Hi Niels

Spec sheets below for the motor/box I have used its a MFA975D1041 ratio 140 to 1 listed as 67rpm @ 12 volts though there is a +/- 12.5% on speed, mine is nearer 85rpm on 12 volt. You can see the gearbox torque figures on the sheet, cost of motor around £30 and Farnell stock them, others sell them but watch pricing. There are other makes of course Maxon are excellent but a bit pricey, Mclennan and Micromotors are also good. Just be careful of the cheap motors on Ebay, some are good but some are not.

I have some experience of the MFA motors as I used them in my Electric RC aircraft days. The 975D comes in 5 ratios and I went with middle ground thinking the others either side either too fast or too slow. Quality is very good and they are very robust having a heavy duty feel about them considering their size. The box is a planetary type which is good on efficiency and well engineered.

Nothing clever on my part re the motor/box, a mix of trial and error and a bit of gut feeling for what would be about right which fortunately worked out. The range of speeds and the torque seems about right for most turning/parting or at least for how I will be using it. Having a driven feed for parting was probably the main reason I decided to do the mod.

Certainly worth doing if you fancy adding a drive to yours, a short video below of parting which you asked for it works well.

Ron

[Niels AbildgaardParticipant @nielsabildgaard33719]

Lovely parting off without drama and tears.

What was diameter of subject?trying to calculate feed/rate that is on the low side for my taste.

918 lathes are wildly underated here and go between 250-500 £.Must have one.

[Ron LadenParticipant @ronladen17547]

The work is 1.75" steel unknown but it cuts nice. When it comes to parting off I throw feed rates out of the window I just aim for a cut with no issues or problems if it takes a bit longer I don't worry. I just think of the material the diameter and guestimate a spindle speed and feed, if the machine sounds happy so am I. I do tweak the speed and feed if I think I can get away with it or if it needs it but otherwise I leave well alone.

That's just me though I'm the same with turning and milling I go by the feel and sound of the machine regardless of what the books and charts say.

[Ron LadenParticipant @ronladen17547]

Can anyone with a 5 inch 3 jaw tell me its capacity across the inside Jaws, I appreciate it may differ across the makes but would have thought they would be similar.

I have done a bit of a search in a couple of places and it's coming up with approx 40mm which I find a bit odd as my 4 inch 3 jaw can take 40mm, I was expecting more like 55mm.

[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by Ron Laden on 31/07/2020 14:47:54:

Can anyone with a 5 inch 3 jaw tell me its capacity across the inside Jaws, I appreciate it may differ across the makes but would have thought they would be similar.

I have done a bit of a search in a couple of places and it's coming up with approx 40mm which I find a bit odd as my 4 inch 3 jaw can take 40mm, I was expecting more like 55mm.

A picture of where and what 40mm will open a torrent of wise guy comments.

[Ron LadenParticipant @ronladen17547]

Seems most 5 inch 3 Jaws are listed at around 40mm but the practical dimension is listed as 50mm well that's what I found on a couple of sites.

[Martin ConnellyParticipant @martinconnelly55370]

There is a reason for outside jaws, large diameter parts up to the diameter of the chuck. The issue with large diameters and inside jaws is how much jaw stick out beyond the chuck diameter is acceptable. If you are buying a new chuck I would suggest getting one with inside jaws, outside jaws and two part soft jaws.

Martin C

Ps There have been a couple of threads regarding jaws with teeth snapped off. This is probably due to people using inside jaws beyond their design capacity. 

Edited By Martin Connelly on 02/08/2020 09:33:57

[Ron LadenParticipant @ronladen17547]

Thanks Martin yes I am thinking of getting a 5 inch chuck it comes with inside and outside and soft jaws are available. I wouldn't use the inside jaws with them relying on the last tooth far too dangerous, I was just curious as to the capacity of the inside jaws on the 5 inch (used correctly) hence my original question.

Going with the 5 inch from ARC £50 and a 1.5" x 8 tpi backing plate, price is very good and I am hoping it will be as good as the two chucks I had from them for the mini lathe, they were spot on making them great value.

[Ron LadenParticipant @ronladen17547]

Just thought it best to check with you guys so I dont make an error, will a carbide insert (ferrous type) manage to cut the jaws of a 3 jaw chuck ok..? I know the jaws are hardened but wondered how much.

Edited By Ron Laden on 31/01/2021 13:47:34

[Ron LadenParticipant @ronladen17547]

Just thought it best to check with you guys so I dont make an error, will a carbide insert (ferrous type) manage to cut the jaws of a 3 jaw chuck ok..? I know the jaws are hardened but wondered how much.

[Ron LadenParticipant @ronladen17547]

Just thought it best to check with you guys so I dont make an error, will a carbide insert (ferrous type) manage to cut the jaws of a 3 jaw chuck ok..? I know the jaws are hardened but wondered how much.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Ron Laden on 31/01/2021 13:45:23:

Just thought it best to check with you guys so I dont make an error, will a carbide insert (ferrous type) manage to cut the jaws of a 3 jaw chuck ok..? I know the jaws are hardened but wondered how much.

Edited By Ron Laden on 31/01/2021 13:47:34

See if the jaw can be scratched by a file first. Whilst Carbide is harder than the hardest steel, a very hard steel will give carbide a run for it's money. If the jaws scratch, they're relatively soft and carbide has a good chance. If the file bounces off, then carbide will struggle more. Carbide will win the fight but it could be painful.

Grinding is better for hard materials.

Re jaws, the limit is set by the number of teeth engaged in the scroll, and how brave you are!

The 3-jaw on my HV5 will just hold 65mm diameter but 3 of the teeth are completely outside the chuck:

Looking inside the slot, it can be seen only one tooth is engaged with the scroll, and at full extension it's marginal: any further and the jaw disengages.

I would trust this chuck up to about 50mm diameter, and might risk holding a light job up to about 60mm. Depends on the design, other chucks might be a little better or a little worse. Since a big job levered itself out of a chuck with a metal bending bang I've been less brave! The further the jaws come out, the more nervous I get, but it's a judgement call.

Dave

Edited By SillyOldDuffer on 31/01/2021 14:25:28

[Roger BestParticipant @rogerbest89007]

Great work Dave. Super find and lots of clever stuff since.

Did I see that moving the switch to the left means it goes away from you, rather than moving the switch away from you means the machine goes away from you?

[wally robsonParticipant @wallyrobson55094]

I've just acquired a warco 918 looking in excellent condition. looks hardly used but really disappointed with it. The idea of having to take tension off belt before starting to avoid breaking bel, seemed very odd and maybe design fault? Any way I played their silly game to the letter but when working with it the belt flies off regularly no matter how carefully I do it. Also the 5mm vee belt regularly twists itself. can't seem to get a good finish on mild steel as slight chatter marks appear. People on here seem to have good things to say about them. I'm not new to turning being 77 and in the game most of my working life. Just don't like the lathe. Any input gratefully received

wally

[Michael GilliganParticipant @michaelgilligan61133]

Posted by wally robson on 22/04/2022 00:13:48:

I've just acquired a warco 918 looking in excellent condition. looks hardly used but really disappointed with it.

[…]

People on here seem to have good things to say about them.

.

The cynic in me would note that Warco appears to have a reputation for providing ‘no quibble’ replacement when faults are reported … people take comfort from that, and say good things about them.

MichaelG.

[JasonBModerator @jasonb]

To save people replying in two separate places can I direct further replies to Wally's other thread.

[Author]

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