Dr Al's Latest Folly

[Dr.Al]

The bulk of this morning has been spent working on a shield to keep the sawdust out of the motor and inverter. I started with a big sheet of 0.8 mm thick steel, left-over from when I made some drawers (which you can see in lots of photos in this WIP). I marked out where I wanted the cuts to go, then did it again after getting it wrong first time (measure twice, and all that):

I then used my lovely little metal cutting circular saw to cut along the lines:

To remove the bit that goes over the spindle, I started by bending it back and forth to make the line a bit weaker and very clear:

I then considered a few different approaches, none of which seemed viable, before resorting to abusing one of my cheap and nasty chisels that I reserve for such abusive treatment:

One run along each side of the cut line and the thin steel was severed:

After roughly resharpening the poor chisel, I used a file to clean up the edge:

I then used my home-made sheet metal folder to form the sheet into shape:

For the last fold, I started with two clamps at each end of the bar:

Then moved one of them once I'd folded it up as far as I could (I didn't have any clamps with sufficient jaw depth to have a clamp from the front edge):

All done:

Before welding it, I did a quick test fit:

Then it was just a case of applying some tack welds:

Then using some more of the 3030 extrusion as an arm rest to try to get as comfortable as possible for welding:

The angle grinder then hides all the evidence:

When I made the shield, I hadn't really thought about how to mount it (although I had realised I needed to, I'd just put off the thinking!)

I rummaged around in my various metal stores and found a promising looking bit of aluminium angle. It already had a couple of holes in it; I added some more:

I then clamped it to the steel sheet with another bit of scrap aluminium at the back and then drilled through:

I did a similar process on the back end of the shield as well and with that, the shield is finished (give or take some rounding off of edges and some paint at some point):

It's held to the 3030 extrusion with two drop-in t-nuts at the front; the back just rests on the extrusion. I wanted it to be quick to remove as it'll have to be removed to adjust belt tension or to dismantle the lathe for storage. I thought I'd taken a photo of the finished shield in situ, but I can't find it. No doubt more photos will be taken in due course!

 

[Dr.Al]

Another outstanding job is to make the knob for what I've been calling the tool rest slide but is apparently known as the banjo. The knob will turn the hex bar that runs through the banjo. I started by modifying the end of the hex bar to have a smooth shank section on the end:

I then grabbed a bit of 16 mm diameter 303 stainless bar and drilled an 8 mm hole, 20 mm deep, then broached it as deep as the rotary broach would go. The 8 mm drill then went back in to clean out the detritus from the broaching operation.

It got flipped around in the chuck and, with the lathe running backwards, I shaped the end:

It then went in a collet chuck for a hole to be drilled and tapped for a grub screw:

Finally, the collet block was tilted up to allow the cross hole to be drilled for the handle:

After preparing a handle (by rounding over the end of a bit of 8 mm bar), I glued it in place with Loctite 603:

After leaving it for an hour or so, the glue was still not holding (it usually cures in about 5 minutes). My first suspicion was that I'd made the hole a bit big, so I drilled it out bigger and used a 10 mm handle. That didn't stick either, so I started again and made a completely new handle body (with an 8 mm hole again). I meticulously cleaned everything with acetone and tried gluing again but after an hour it was still quite loose. I'm beginning to suspect it might be the age of my bottle of Loctite 603 (which must be getting on for 10 years old now). I've left it for now: if it hasn't cured by the morning, I'll probably just cheat and weld the two bits together!

Next up is another job that's firmly on the "arguably pointless" pile: making a spindle gouge so that I can turn something with the lathe once it is finished. I say this is pointless as I'm intending to buy some HSS lathe tools very soon and at that point it's unlikely I'll ever use the home-made one again. However, in the spirit of "try to make everything and buy nothing", I felt I ought to give it a shot.

What makes it slightly more difficult is that I've never held a spindle gouge in my life and it's difficult to be confident of the geometry based on photos online!

I started with a bit of 16 mm silver steel. I've got a 10 mm double-ended ball-end end mill. I've honestly no idea where it came from (I guess I bought it at a show at some point) and it has never been used. Now's its chance! The silver steel got held in a collet chuck and the mill spindle aligned with the centre of the bar:

I then gradually milled the silver steel away until I'd reached a depth of 13 mm and hence there was 3 mm material left all the way round the slot:

A big end mill was then used to bring the top surface down a bit and hence remove the sharp edges at the top of the slot:

Rather than waiting until after hardening, I decided to rough out the bevel now. This has the considerable advantage that I could be quite aggressive with the bench grinder as I didn't really care about overheating the edge:

It felt a bit wasteful to use such a long length of 16 mm silver steel on what is essentially a throw-away project, so I decided to cut it down to length and use an extension bar. After cutting it down, I faced the back edge and turned an 8 mm diameter shank on the back:

I then filed a flat on the shank:

A bit of 16 mm EN1A was faced off and an 8 mm hole drilled and reamed in the end. The EN1A bar will act as a handle for now.

Next up was heat treatment. I covered the part in a mixture of boric acid and methylated spirits. That mixture helps stop scale forming on the piece, which makes clean-up much easier later. It then got attacked with the MAPP gas torch:

Once it was glowing red and wouldn't stick to a magnet, I dunked it in some water and wiggled it round until it stopped fizzing.

In this photo, you can see the effect of the boric acid, which stayed put in the slot, but didn't stay as effectively on the body:

After a quick rub with some 180 grit wet-and-dry, I tempered it with the MAPP torch again. A bit of 10 mm bar was reduced in diameter slightly (about 9.75 mm at a guess) and wrapped with wet-and-dry paper. That was used to clean up the slot, working up through the grits until I got bored.

Finally, I sharpened the bevel and gave it a hone and I think it's ready for use:

This photo shows the full tool: not the most ergonomic of handles, but hopefully it'll do the job for the limited use I expect this to get:

 

[Dr.Al]

Yesterday's attempt at gluing (the fourth one I think) hadn't cured overnight, so I started today by welding the knob in place:

It then got a bit of attention with a wire brush before fitting it:

The next job was to work on a shorter tool rest. Being shorter (and aiming for shorter than the stock that it's made from) allows for a slightly tweaked process of making it. The first thing I did was clamp a vice in the mill vice and used that second vice to hold the stock upright. I could then drill a centre hole, just in one end this time. As I was drilling more accurately (using an edge finder on the edges of the stock and moving in a controlled amount) by virtue of being on the milling machine, I could use a slightly larger centre drill without risk of blowing out the edge:

I could then mount the piece in the four jaw chuck (using a couple of offcuts of steel as I couldn't get the jaws close enough to each other to allow such off-centre turning):

As it was held quite robustly in the chuck, I could run the lathe quicker than I did when making the longer rest and that meant that turning it down to size was much quicker:

After using the bandsaw to chop it to length, I milled the two ends with an end mill (which handily gave me a very accurate gauge of the centre) and then drilled the hole for the support post:

After turning it through 90°, I drilled and manually tapped the the grub screw hole (using the chuck to keep the tap aligned, but turning the spindle by hand):

The two rests side-by-side for comparison:

With that done and a bit of walnut made octagonal with the bandsaw, there was really nothing for it and I bravely (stupidly?) decided to set up a camera on a tripod to video my very first attempt at woodturning...

The bit of plywood in the background was there to keep the shavings from covering all the tools mounted on the wall, although it didn't seem that bad in practice.

After reviewing the video on the camera's screen, I realised it wasn't that clear (I'll never be a youtuber!), so I moved it a bit closer and filmed my second ever attempt at woodturning!

A couple of photos of the result:

I also braved a second attempt (with the camera off this time) and turned a longer piece with the long tool rest (the photo was taken after vacuuming up the mess!):

Some more photos:

With the cover off:

From my point of view, that's basically a finished lathe. I started on 8/2/2024 and today is 10/3/2024, so it has taken me just over four weeks to make. When the weather gets a lot warmer, I'll paint the bits of it that I think would benefit (painting Tractol is a lot easier in warm weather I think). Immediately before that I'll probably run the angle grinder over all the corners to round them over a bit. However, I'm quite happy to put painting off: I absolutely detest painting!

It seems to work pretty well from what I can tell with zero experience. I'm sure I'll do a lot more playing/experimenting over the next few weeks (especially once I've bought some proper lathe tools to go with it).

This afternoon's job will probably be to have a go at turning a chisel handle (as I said I would try to do that without buying anything, so I need to make it with the tools I've got).

 

[Dr.Al]

This afternoon I had a bit of a play and have made my first chisel handle, so I'm happy that I've proven that it's possible with the stuff I've made. I can now buy some proper lathe tools!

In all honesty, this one is destined for the fire: it ended up a lot shorter and narrower than I intended, mainly as a result of several tool dig-ins as I was shaping the back end. To say my technique needs work would be an understatement! Nevertheless, I've proven that the lathe works and I've seen what a walnut chisel handle might look like, so I'm still very pleased.

 

[Kram]

Nice work, it looks good.
Commercial tooling may be plain carbon steel rather than silver steel, so I imagine yours will be better quality, and same for the drive centre.

 

[Dr.Al]

I thought it was probably about time I posted an update on how things have been going with the lathe. Since finishing the lathe I've done a bit of shopping (and a lot of sharpening!): I had a weekend in Lyme Regis and while I was in the area I visited Axminster Tools and bought a chuck and a set of turning tools to get me started. I then visited a superb second-hand tool shop in Beer (Dolphin Antiques) and found that they had a decent selection of used lathe tools and also a big array of second-hand chuck jaws (for £15 a set) that fitted the chuck I'd just bought. I can resist anything but temptation, so I got a bit carried away and now have several different chuck jaw options and a selection of cutting tools to experiment with, along with a cheap second-hand pen mandrel in case I ever get tempted to try pen or pencil making. On note unrelated to woodturning, I also bought a Quirk router as I've been looking out for one for a while. Photo of the haul from Dolphin Antiques:

I've no idea at all how useful those chuck jaws will be, but at £15 per set it seemed daft not to buy a few varieties (I also have a set of so-called "Type C Dovetail Jaws" that came with the chuck). The buttons that came with the button jaws are still sealed in their packet, so I don't think the jaws have had much use! Dolphin Antiques had a lot more jaw types that I didn't buy, so I can at least claim to have been a little bit restrained! If it turns out that the jaws aren't especially useful for what I want, I can probably sell them for more than £15 a set anyway.

With a total of 10 turning tools and a selection of chuck jaws, I am now firmly in the "all the gear, no idea" category when it comes to wood turning!

On my return from the trip to Dorset, I tried fitting the chuck and found that it didn't fit the spindle. There were two problems: the threaded section was too long (and hit the back of the jaws) and also the register is too small (33 mm where it should have been 34 mm), so doesn't centre the chuck properly. The thread is a nice snug fit, so it would probably still run true, but I think the register is supposed to be the thing that ensures concentricity.

The over-long thread isn't a big deal: it's easy to remount the chuck on the metalworking lathe and shorten the nose (and I did that to check there were no other problems). However, making the register bigger would be an issue: I could consider shrink fitting some larger steel over the top and then turning it to size, but it would be much easier to just make a new spindle, so that's what I did.

To be honest, it wasn't a surprise that the chuck didn't fit. I had suspected that the chuck-mounting thread might be a problem, so I took some vernier calipers with me to Axminster Tools and measured the nose of one of the lathes in the shop: that was when I realised the register size I'd found on-line was wrong. The nose of the new spindle is made to match the dimensions of one of Axminster's lathes.

Anyway, the new spindle was made in much the same way as the old one and the chuck now fits very well. While I was swapping the spindle, I also replaced the front bearing with a sealed angular contact bearing - I wanted to swap it for a sealed type and since I had to buy that I figured an angular contact type might be better.

The new spindle fitted with the angular contact bearing:

I'm still a long way off making any proper use of the chuck, although I gave it a try just to check it span on the lathe okay:

I've been experimenting with the "proper" (as opposed to home-made) lathe tools and I've definitely got a lot to learn. I'm okay with taking a square-section piece of timber and turning it cylindrical with a spindle roughing gouge and then making it smoother with a skew chisel, but I'm a long way off being comfortable with any type of shaping at all. I've managed a few goes at very simple shaping with the skew chisel but also had quite a few less-successful attempts. So far I've been even less successful with a spindle gouge. I'll keep practising!

I've also sent an email to the membership secretary of the Gloucestershire Association of Woodturners to try to join (or at least join the membership waiting list), but haven't heard anything back thus far. They offer courses for beginners, which would be great if I can join, but failing that I might have to look elsewhere for tuition. In the meantime I've got the next week booked off and no plans (and the weather forecast isn't looking great), so I will have plenty of time for more practice (and for watching more Richard Raffan youtube videos).

A couple of random photos from my experimentation:

Another thing I've been starting to think about is where to store the lathe and the lathe tooling. For the lathe itself, I got a couple of offcuts of fairly thick steel and welded them together (after shaping one a little with a flap disk and drilling and countersinking some mounting holes in the other):

The holes in the "prong" were already there in the offcut I used: they serve no purpose here. That bracket got screwed to one of the joists and I could then mount the lathe bed to the bracket:

It's right at the limit of what I can lift (and unusually for my lanky frame, I needed a step ladder to feel comfortable getting it up there) and it's probably the first real test of my welding skills as I've never done anything quite so structural before!

The eagle-eyed among you will notice another modification to the lathe: the bed has been raised up a bit higher (it's now on two pieces of 3030 extrusion instead of just one). I was finding the lathe a little low so I thought raising it a bit would help. If I have to raise it any higher again I'll either have to raise the motor at the same time or buy a longer drive belt!

Regarding storage, I still haven't figured out where to store the motor & drive assembly:

The motor is very heavy, so I don't want to have to lift it very high up (so no option of hanging it from a joist) or put it low down (so no option of sliding it under something, not that there's any floor space under anything in the workshop!). I'm rather short of options, so it might just have to live on one or other bench for now until I can figure out a better option.

 

[Robotstar5]

<snip>
The motor is very heavy, so I don't want to have to lift it very high up (so no option of hanging it from a joist) or put it low down (so no option of sliding it under something, not that there's any floor space under anything in the workshop!). I'm rather short of options, so it might just have to live on one or other bench for now until I can figure out a better option.

What about something similar to a pulley clothes airer but use both pulleys on a single line to reduce the llifting effort.

 

[Dr.Al]

What about something similar to a pulley clothes airer but use both pulleys on a single line to reduce the llifting effort.

Interesting thought. Yes, maybe. I'll still need to clear some space on the joists for it to attach to (every joist is already full of stuff!) and I'll have to think what I'd want it to be over (I don't want something hanging over the area I walk just for safety's sake). I'll have a ponder...

 

[Dr.Al]

Most of today has been spent making a simple "Lazy Susan" tool holder. It's made out of some plywood pieces (which were made circular with an electric router) and various bits of steel, aluminium and copper. The frame is made out of more of the 3030 extrusion that I got out of the skip (I've still got loads left; it's really handy stuff to have around). The bar that runs through the middle is a bit of 12 mm diameter mild steel (the cheap stuff sold for construction applications). The ends of the bar were turned down to 8 mm and then various bushes were made out of 30 mm EN1A to centralise the 22 mm copper pipe that separates the layers. The ends of the bar fit into some more steel blocks that are screwed to the aluminium extrusion and have a hole bored for a skateboard bearing (which are very cheap to buy and I have quite a lot of).

As the bar runs in bearings, it spins very freely (possibly a bit too freely: it rotates when there's a gust of wind!). It's attached to the bench using a simple 20 mm diameter bit of steel screwed to one of the bits of extrusion: that drops into a dog hole on the bench. As a result, it can be placed anywhere along the length of the bench, although I found this position quite comfortable for use:

I also drilled & counterbored some holes in a bit of 25 mm × 50 mm aluminium bar and screwed it to the holes in the end of the lathe bed:

The bigger of those holes is 21 mm diameter and allows the tool holder to hang off the end of the lathe bed when the lathe is stored away:

As well as the motor storage (which I'm putting off for now) I still need to figure out storage for the chuck & jaws and also all the various Morse taper bits and bobs. For the latter, I might make something that fit on the Lazy Susan in-board of the tools, but I haven't decided for certain yet.

After all that, I thought it would be good to have another go at turning with a spindle gouge and I think something clicked this time: it felt a lot more in control. I think (although I'm not certain) that when I'd been experimenting before I was trying to control the tool with my left hand (by the rest), whereas today I was doing a lot more with my right hand (on the handle) and it felt a lot easier. I'll keep practising, but this simple bit of shaping seemed fairly straightforward:

The finish is a bit rough (lots of lines where I didn't maintain continuous smooth movement: a problem I suffer when TIG welding as well!), but hopefully that will get better with practice.

 

[sparkysy]

That chisel holder is an excellent solution, I may have to pinch that idea!

My SWIMBO is into woodwork and has turned some really nice bowls and candle sticks, she did some with captive rings on that were really cool!

 

[Dr.Al]

It felt about time to do another update on my progress. I feel like I'm getting the hang of the spindle gouge and the skew chisel. I've also used a parting tool a couple of times and that was very straightforward. The bowl gouge, however, is proving to be a lot more challenging!

Anyway, a few things that I've done. First of all, the 3D-printer has been rather busy. It has made cylindrical thingy that sits on the Lazy Susan tool holder and holds various Morse Taper widgets and such-like:

Similarly, I made a liner for the box that the chuck came in. The liner holds all of the jaws I bought from Dolphin antiques as well as the bits and bobs that came with the chuck. There isn't much room for growth, but I can't imagine me needing any other chuck bits for a long time (and there isn't really any more room in that box anyway). I can't close the lid with the box as-is, but I can always replace the cardboard box with a wooden one if/when the inclination arises:

The Altoids tin is full of the M5×12 screws that hold the jaws to the chuck (and which came with every set of jaws, so I have loads of them in there).

With all the chuck jaws laid out, I also thought it would be useful to make a custom version of Axminster's "Speed Sizer", with holes for all the jaws that I have. I've used it a couple of times so far and it seems to work very well:

One of the things I used it for was making a couple of bowls (more on that later). This was a work-in-progress shot of the first one (made out of Sweet Chestnut) - as you can see, those button jaws only just fit on my little lathe!

To say that making that bowl was fraught would be a bit of an understatement. I don't think I've quite got the hang of the bowl gouge. On the second bowl attempt (photo coming later), I was okay using it to shape the outside of the bowl and also to roughly shape the bottom of the inside. However, I'm really struggling to figure out how to hold it to cut the inside near the rim. I can do what I think is a scraping cut (with the open mouth of the flute roughly parallel with the inside of the bowl), but when I try to ride the bevel and do a more conventional cut, it all goes wrong. I think I'm probably working on an unsupported bit of the bevel, but I can't quite figure out what to do with my hands to make that not be the case.

The next photo shows the marginally more successful second bowl attempt (made out of Sycamore). A lot of scraping was used to sort out the mess I made with the bowl gouge! I also had a go at making a couple of pens (Sweet Chestnut and American Black Walnut, both with sanding sealer followed by wax) and a couple of pencils (both American Black Walnut and both finished with Mike's Magic Mix) - while I'm not that interested in turning pens and pencils, they were quite useful as spindle gouge practice without worrying too much about wasting lots of wood!

With all those various practice pieces done, I couldn't really put the chisel handles off much longer. A rough guide to the process I went through follows.

The first thing I did was use a roughing gouge to make a load of cylindrical bits of English Walnut. I then cut each length into three pieces, resulting in a big pile of cylinders, all about the same diameter and length. Each one was then held in the chuck and a little 3D-printed gauge thing (basically a miniature version of the "Speed Sizer" thing) was used to mark the size of the ferrule spigot:

A skew chisel was then used to shape the spigot. I started with a peeling cut to get it roughly down to size, then used the pointy end to cut the shoulder. I then crept up on the final size using planing cuts and checking against the ferrule often. Most of the ferrules went on with a bit of mallet-based persuasion; a couple slid fairly smoothly so I added a few drops of superglue to hold them more firmly in place (although I imagine they'll be pretty rigid once the chisel blade is shoved in).

Once the ferrule was fitted, I used the skew chisel again to skim the end down flush and then a spindle gouge to rough out the approach to the ferrule.

Finally (for the first setting), I drilled a 9.4 mm hole in the end.

Rinse and repeat...

With lots of them done (more than I need, but I wanted some spares in case of problems), I held the ferrule in the chuck for shaping:

The spindle gouge did the bulk of the work, then I took a light planing cut with the skew chisel. I'm happy to say that (so far) I haven't had a single "catch" from either the spindle gouge or the skew chisel when making these chisel handles (unlike my bowl-making endeavours!)

The last thing to do before removing the handle from the lathe was a bit of sanding (150 grit and then 240 grit):

Despite being in batch production mode, I couldn't resist fitting a handle to check everything looked okay...

... and applying a quick coat of Mike's Magic Mix for good measure:

The progress so far:

The pale coloured handle fitted to a chisel was my trial run to check the process. The wood is still English Walnut, but it's mostly sap wood (it's not obvious from the photo, but it has been oiled and yet is lighter than the other un-oiled handles). I'll almost certainly remove the blade from that handle and replace it with one of the newer ones once I've made them all.

 

[Migmac]

Very nice

 

[Blobber]

Nice work as usual, I really dont know where you find the time, you must have 36 hours in your days!

 

[Dr.Al]

Nice work as usual, I really dont know where you find the time, you must have 36 hours in your days!

I've had the week off work, which has helped a lot!

 

[Dr.Al]

I had another go at a bowl yesterday and it went a bit better this time, although I wouldn't go so far as to say I enjoyed the process. I started with the other half of the bit of sycamore that I turned the last bowl out of. I mounted it using a screw chuck and turned the outside with the bowl gouge. That went fairly smoothly (and the 3d-printed speed sizer thing worked well again):

It then got reversed and held on the dovetailed base and the inside was turned. This went a lot better than last time - I don't think I'd realised that I needed to have the handle end of the bowl gouge right over the far side of the lathe. A shorter handle would probably have helped: the bench top kept getting in the way!

Anyway, it went okay-ish (there was still a fairly amount of scraping to tidy things up, followed by lots of sanding, but no actual catches). Overall though, I didn't really enjoy making it and I can't see me making many more bowls, so I guess I don't have to lose too much sleep over whether my technique is quite right or not.

I also finished off the shaping of the rest of the handles yesterday:

They had their first coat of Mike's Magic Mix yesterday and the second one today (I'll probably leave it at two coats):

I've spent almost the entirety of today tidying the workshop. It was in an awful state and it had been a long time since I last had two clear benches. It was a real struggle at times to figure out what to do with some of the stuff, but in the end it came out looking good, so I took some photos (something I try to do on the rare occasions that the workshop is tidy!)

 

[Dr.Al]

The first job this morning was to finish off the chisel handles. They've had two coats of Mike's Magic Mix and I decided that was enough for now. I can always add more coats later if necessary. I took the old handles off the chisels and lined them up with their new handles:

Then it was just a case of fitting them:

The new ferrules are a different diameter to the old ones, so I also had to make a new storage rack, but the 3D printer did most of the work there.

I said only yesterday that I couldn't see me making many more bowls. That's still true, but I wanted to "test the envelope" of the lathe, so I decided to have a go at making a much larger bowl. I started by sawing the end off a large (260 mm wide and 75 mm thick) piece of beech that I had ferreted away. I then drew a couple of circles on the face, one 250 mm diameter and one 84 mm diameter (the latter was chosen to match the faceplate thing I'm going to use to mount it):

The bandsaw then got used to cut as close as possible to the outside circle. The centre height of the lathe is about 128 mm, so the absolute maximum diameter workpiece would be 256 mm. With a 250 mm blank, it has to be very close to circular before I mount it on the lathe or the corners will hit the bed.

After drilling some pilot holes in the face, I screwed the faceplate to the beech blank with some 5 mm × 50 mm wood screws and mounted it in the chuck jaws:

There's a couple of millimetres of clearance under the blank, but that's it:

Turning the outside proceeded relatively smoothly. The (1.1 kW) motor has loads of power so there were no issues there. I still had a few catches with the bowl gouge and I ended up doing quite a lot of scraping (and then loads of sanding) to clean it up, but it came out okay all things considered:

After a coat of sanding sealer and some beeswax...

...it was time to turn it round and mount it using the dovetailed pocket I'd turned in the base:

To make hollowing a bit easier, I started by putting a 45 mm Forstner bit in the drill chuck and plunging it in. I then used the bowl gouge to cover myself and everything else in beech shavings. In progress:

Once again, the final shape had a lot of scraping and then loads of sanding done. I probably could have kept going for much longer, but I was getting thoroughly bored of sanding and decided I'd had enough. The finished bowl still mounted on the lathe:

The final photo shows it lying on a bed of its entrails!

 

[Dr.Al]

I was using the lathe again this morning to make another tool handle and I noticed that there was a lot of vibration. After a quick investigation, it became clear that the motor pulley was wobbling on the motor shaft and that was making the motor vibrate. I'm sure I could deal with it by clamping the motor assembly down better (it was only held to the bench with one clamp), but I'm not happy about the level of vibration.

I mentioned in an earlier post that the motor pulley had been a pain to fit as the shaft of the motor turned out to be wider at the end than at the base. I think what's causing the vibration is that the pulley doesn't have a perfectly fitting hole in the middle (as it needed to be enlarged to get it over the end) and hence it's moving back and forth a bit as the shaft rotates. The only decent way I can think of dealing with this is to sort out the motor shaft (and then make a new pulley).

The first step was to dismantle the motor to have a better look at what's going on:

I mounted the shaft between centres on the lathe to see whether that would allow it to run fairly true (and hence give me a relatively easy way of making the shaft a consistent diameter and concentric with the motor axis).

Running the lathe at a low speed (and with no drive dog, so just relying on friction to spin it), it was obvious that the shaft wasn't running true relative to the two centres. This is a close-up of the questionable end:

It's not that obvious in the photo, but the tip balloons out a bit. The bearing sits on a register that looks to be 19.05 mm (3/4"), so there's no way I'd be able to get the bearing (and hence the retention plate and the fan) off without first doing something about the end of the shaft (the shaft end is 19.35 mm at the tip). To make things even more difficult, the shaft has been hardened, so turning it won't be trivial.

Looking at the end of the shaft, it's clear that it has had some abuse at some point in its life: the centre hole looks pretty awful (which won't have helped it run true when mounted between centres):

Compare that with the centre hole on the other end of the shaft, which looks a lot better:

I'm not sure what to do about this to be honest. I've thought of a few approaches, but none seem great.

Approach 1:

• Re-assemble the motor
• Run it and, while running, use an angle grinder to get the end of the shaft down to less than 19.05 mm.
• If there's enough 19.05 mm shaft left to be usable and it runs concentrically with the bearing, stop there.

Approach 2:

As approach 1, but assuming the shaft isn't looking sufficiently usable after the angle grinder attention.

• Pull the bearing, bearing backing plate and fan off and then re-fit the bearing.
• Mount the shaft on the lathe, using a fixed-steady to support the outside of the bearing.
• Try skimming the shaft with some carbide tools to get a smooth shank at some diameter or other (< 19.05 mm)
• If I'm not feeling confident in the concentricity of the result, reduce the diameter even further (< 15 mm probably) and shrink fit a (non-hardened) sleeve over the top, then reassemble the motor and mount the entire motor to the bed of the lathe and run the motor while turning a new concentric shank from the non-hardened sleeve.

Approach 3:

• Just cut the end with an angle grinder, hopefully leaving enough of a concentric section to be usable (similar to approach 1, really).

I'm probably leaning towards approach 1 (with a lot of hoping that I can do it without having to resort to approach 2), but I'd welcome any other suggestions.

 

[Seadog]

Use the fixed steady, centre it and re-drill the centre. A carbide centre drill might be needed, fron what you're saying, but I think it's unusual to harden the armature spindle.

 

[Dr.Al]

Use the fixed steady, centre it and re-drill the centre. A carbide centre drill might be needed, fron what you're saying, but I think it's unusual to harden the armature spindle.

I was surprised it was hardened as well, but my files just seem to skate off the surface. That's my usual way of testing.

I don't have any carbide centre drills unfortunately (note to self: buy some carbide centre drills!). Approach 1 seems to have worked anyway....

 

[Dr.Al]

I decided to go with Approach 1: grind the end down a bit and rely on there being enough concentric shaft left after the mangled bit at the end. I started by reassembling the motor (with some fresh grease in the bearings as it seemed sensible while the motor was apart) and then got the motor spinning. A flap disk in the angle grinder applied a slight chamfer thing on the end. Once it got this far, I measured it and couldn't find any area where the diameter was over 19.05 mm, so I stopped:

I then had to make a new pulley (as the old one had an oversize bore). That was done in much the same way as the old one, with the only difference being that I used my home-made filing machine (aka die filer) to cut the keyway and that I drilled and tapped a hole for an M6 grub-screw (which was always the intention on the original one, but the original one went on so tightly that it didn't seem worth bothering with):

With that done, I could reassemble the lathe and give it a test spin. I was feeling confident so I decided to spin it up without any clamps holding it down to the bench. It ran smoothly up to speed with no noticeable vibrations and stayed put on the bench. That's much better than it was before. I'll still clamp it down when I'm doing any turning, but it's nice to know it runs well without the clamps. It had seemed okay when I did the first few bits of turning with the lathe, but the vibration had been getting steadily worse. I'd guess that the pulley bore being a bit mashed by the end of the motor shaft meant that it wobbled a bit and that caused wear on the pulley bore, which meant it wobbled a bit more and so on. Hopefully the new pulley will last a lot longer now that the motor is sorted.