In what way are cheap lathes bad?

[JakeS]

I've recently come across a bargain-price second-hand cheapo lathe (seems to be the same as the current Clarke CWL12D, but with a different model number), with the thinking that I didn't know whether I'd like it or be any good at it, and I didn't want to spend hundreds of pounds to find out. And seriously, the lathe - rusty but perfectly functional - cost me a whole £20, so I'm not regretting that part.

However, while I've been having enough fun with between-centres turning to invest in a set of Sorby chisels off eBay that set me back twice as much as the lathe did, I thought I'd have a go at cutting a thing-with-a-hole-in - maybe a pencil-holder or something - and have had nothing but trouble with it. Definitely no success!

The first time I tried, I tried truing up the block and mounting it in the chuck, but then almost the moment I touched chisel to the end face of the cylinder (off-centre, so probably my fault) the wood flew out of the chuck and landed on the floor (thankfully missing me and anything expensive).

The second time I tried, I figured I'd screw it to the faceplate... and the moment I moved from the centre while cutting the end, it grabbed and ripped the wood off of the screws.

The third time, I figured that maybe the screws I'd used were too short, considering they were going into end-grain, so I used longer screws. This time it sheared the faceplate casting apart between the threaded part and the face part, and I had to use a pipe-wrench to get the remains of it off the spindle.

Then I re-examined the chuck, and compared it to more-fit-for-purpose and less-cheap-and-crappy chucks I'd seen pictures of on the Internet, and realised that one problem was probably that the jaws were flat and slippy, so I filed a series of serrations in. This time I got a small hollow cut into the end - maybe four or five millimetres - before it slipped in the chuck again.




So, obviously I need a lot of practice, and I probably need to re-re-sharpen my tools again, but basically, my question is this: how much of this experience is expected for a cheap and crappy Clarke lathe, and how much of it should just be attributed to me being rubbish at turning holes in things? I've slowed the speeds down and then sped them up and then slowed them down again to see if it made a difference (most of the above has been on the second-lowest speed setting), I've trued up the end of the cylinder with a parting tool and then careful application of a skew chisel before trying to hollow, and I'm attempting to start in the centre by cutting out a small hollow with a round gouge and then work my way outward.

Is it normal to have to re-seat the workpiece in the chuck after a single catch, and I should just practice and practice until the catches don't happen... or is that just because the chuck is useless and I should replace it? (The body of the thing isn't true to the thread cut in it, so I'm perfectly open to this being a possibility anyway!)

Is it normal to have to be very careful with faceplates to avoid breaking them, or is it just a result of using a dodgy cheap-cast-iron job and one lovingly machined out of high-spec stainless steel (or whatever!) would have soldiered on?

Are there any other obvious things I have to take into account with the lathe I currently have while deciding whether it's worth investing in a more-capable one?




I have managed to produce one small pot, but only by turning the outside shape between centres and then hollowing it out with a forstner bit on the pillar drill... and the lid doesn't fit properly. ;-)

 

[CHJ]

........The first time I tried, I tried truing up the block and mounting it in the chuck, but then almost the moment I touched chisel to the end face of the cylinder (off-centre, so probably my fault) the wood flew out of the chuck and landed on the floor (thankfully missing me and anything expensive).
...

Sounds like you are attempting to hold the wood in a standard engineering chuck, not in a wood turning scroll chuck with dovetail or gripper jaws.

Your description of catches and accidents as soon as you attempt to touch the endgrain smacks of not appreciating the need for correct use of gouge bevels to support the cutting edge.

You mention a need to sharpen tools, if you have not sharpened them at least once in every turning session then they are almost certainly not fit for purpose.

If you do not have a copy of the book Keith-Rowley, Woodturning-Foundation-Course I suggest you do so and follow the guidance to work holding and tool presentation before you have any more accidents.
Managing to break a faceplate on something as basic as the clarke lathe is worrying.

 

[JakeS]

Sounds like you are attempting to hold the wood in a standard engineering chuck, not in a wood turning scroll chuck with dovetail or gripper jaws.

Yes (while it seems to be the one Machine Mart sell as a woodturning chuck, I'm not surprised that it's useless), but at the same time, a proper scroll chuck would have set me back five times as much as the lathe cost at least, hence the questions before running out and buying one and assuming it'll solve all my problems!

I was half expecting problems with the original attempt with smooth jaws; after filing serrations into the jaws I expected it to hold the stuff a bit better, though! I appreciate that it's not going to hold the stock so centrally as it would be in a scroll chuck, but I figured that once the outside surface was trued up that wouldn't matter... and that part I'm having no problem with, nice smooth and even surfaces and everything.

Your description of catches and accidents as soon as you attempt to touch the endgrain smacks of not appreciating the need for correct use of gouge bevels to support the cutting edge.

Is it different on the end-grain to the outside circumference of the wood? I'd assumed that the flat of the bevel should be very close to co-planar with the surface you're cutting, in the same way as the bevel on a standard plane, so that the force on the edge is applied back up the shaft of the tool as much as possible and not across the tip...

I did read through as much stuff as I could find in the manual and online before jamming things into other things, but this wasn't a subject I found particularly well-covered; everyone seems to be too concerned with talking about the order of operations and when to put finish on what...


(And I am sharpening the tools relatively frequently - certainly more frequently than my regular woodworking chisels. Probably not as much as once per turning session, but some of these turning sessions have been a bit short... the Sorby gouge I think has probably been in contact with spinning wood for as long as thirty seconds.)



Thanks for the book reference, the contents and index certainly make it look worth a read; I'll pick a copy up.

 

[Spindle]

Hi

What tools have you had the catches with?

Hollowing into end grain, for a beginner I'd recommend using a 1/2" round nosed scraper, which is presented 'in the trail' ie not with the bevel rubbing, on or just below centre (as are all standard scrapers).

Regards Mick

 

[CHJ]

.....I was half expecting problems with the original attempt with smooth jaws; after filing serrations into the jaws I expected it to hold the stuff a bit better, though! I appreciate that it's not going to hold the stock so centrally as it would be in a scroll chuck, but I figured that once the outside surface was trued up that wouldn't matter... and that part I'm having no problem with, nice smooth and even surfaces and everything.

The problem is the lack of surface area you are gripping on, wood is very malleable and the very narrow contact area of the metal chuck jaws is just compressing the timber, first time you put a load on the contact point of the jaw the timber just compresses more and you loose grip.

.....Is it different on the end-grain to the outside circumference of the wood? I'd assumed that the flat of the bevel should be very close to co-planar with the surface you're cutting, in the same way as the bevel on a standard plane, so that the force on the edge is applied back up the shaft of the tool as much as possible and not across the tip.......

With all round gouges regardless of grain direction and the skew chisel the bevel must be in full contact with the wood for support, the bevel is in effect the same surface as the sole of a plane at the rear of the plane blade, the major difference being that instead of the cutting edge protruding as in a plane you tip the toe of the tool a minute fraction to achieve the cut, the knack being that as there is no front sole support to stop the cutting edge diving into the wood you have to control the angle and contact on the rear bevel to maintain the chip thickness.

With scrapers as Spindle says it is more difficult to get a catch (cutter diving into the wood) but not impossible if you don't position it correctly about the centreline of the work.

On the outside of the turning you position the scraper cutting edge below the centreline, any tendency to dig in on rogue grain etc. just pushes the blade away from the work, if it was above the centreline it would dig further in as the piece rotates to-wards the tool.

On the inside of a piece you keep the scrapers above the centreline so that any tendency to dig in throws the scraper into the void beneath it.

Regarding a wood chuck for the Clarke, personally I would forget it unless you can obtain one that has the facility to change the thread inserts to suit a more popular thread standard at a later date.

Unfortunately Turning as a hobby can be an expansive pastime if it is not to become too frustrating working around lack of support equipment.

 

[JakeS]

What tools have you had the catches with?

Mostly with a round gouge, about 6mm across the inside. I've got a round scraper as well, I'll give it a go.

Regarding a wood chuck for the Clarke, personally I would forget it unless you can obtain one that has the facility to change the thread inserts to suit a more popular thread standard at a later date.

Unfortunately Turning as a hobby can be an expansive pastime if it is not to become too frustrating working around lack of support equipment.

Oh, I appreciate that - I'm not averse to paying some money to get decent kit at all. What I'm averse to is throwing money at a problem as a first recourse when it could just be that I'm getting something wrong myself. I'm not too upset about breaking the faceplate 'cause it cost me practically nothing... but I don't want to go out and buy a £150 chuck, or spend £500 on a new lathe, and find that I'm getting exactly the same problems 'cause I just don't know what I'm doing.

As it goes, what sizes of spindle are common in more grown-up lathes? I saw a thread from a while back about the one on a Clarke lathe being non-standard, but it was also different to mine - which seems to be a 3/4" 16TPI thread (a standard UNF thread, so far as I understand).

Thanks for the tips!

 

[CHJ]

3/4 X 16 is a common standard but tends to be on the small side as far as modern lathes are concerned.
1" x 8 is another common one.

Most current European lathes have a 33mm X 3.5mm thread form.

There are a couple of lathe thread lists in The Turning Help Sticky that gives a rundown of the threads and the links to popular makes/distributors machines.

 

[KimG]

Buying a decent lathe and good chuck, while it will not make you a good turner, will at least give you the proper opportunity to learn.

Sounds like you are trying to run before you can walk in a way as it seems possible you are trying to turn too large an item as well. Better to learn how to turn something between spindle first, and how to rough out a piece, that way you will become familiar with the tools and how they cut in a lot safer manner.

The Book Chas mentioned is a must have, even experienced turners have benefited from it, for new turners it should be a standard purchase, it is worth every penny it may cost you as it will help you turn properly and thus get genuine enjoyment instead of frustration and puzzlement.

 

[finneyb]

The third time, I figured that maybe the screws I'd used were too short, considering they were going into end-grain, so I used longer screws. This time it sheared the faceplate casting apart between the threaded part and the face part, and I had to use a pipe-wrench to get the remains of it off the spindle.

Is it normal to have to be very careful with faceplates to avoid breaking them, or is it just a result of using a dodgy cheap-cast-iron job and one lovingly machined out of high-spec stainless steel (or whatever!) would have soldiered on?

Jake,

Look at the screw holes in the faceplate - are they a countersunk hole?
Did you use countersunk wood screws to attach the wood?

If the faceplate screw hole is not countersunk - and mine aren't - then by putting a countersunk head wood screw in and tightened you are stressing the casting by wedging the countersink in the hole; and I suspect the casting failed with the added stress of a catch. What you needed was round headed black slotted screws or similar ie with the underside of the head being straight across so it sits on the faceplate.
Brian

 

[Dalboy]

+1 for the Keith Rowley book. Also try and find a local turning club

 

[Phil Pascoe]

If the holes in your faceplate are not countersunk, countersink them. It's better than using round head screws.

 

[JakeS]

If the faceplate screw hole is not countersunk - and mine aren't - then by putting a countersunk head wood screw in and tightened you are stressing the casting by wedging the countersink in the hole; and I suspect the casting failed with the added stress of a catch.

Originally I had used flat-bottomed screws, but yeah - the only longer ones I had were counter-sunk. I'm not sure I could credit them with the break, though - it happened a fair way away from the screw-holes, right at the part where the collar meets the plane of the plate.

It's worth mentioning that since I got the lathe second-hand, I don't know the history of any of it - for all I know the faceplate was dropped on concrete or whacked with a hammer years ago and came pre-fractured, but it was certainly a bit of a shock!

(I should also note that I did start off with several between-centres practice pieces, and I did get used to the way the tools cut and everything before trying with the faceplate. Sure, I can only claim a couple of weeks' experience, but I didn't jump straight into hollowing something out either. I'm just not having any problem with the spindle turning!)

 

[finneyb]

I'm not sure I could credit them with the break,

I agree, given the position of the fracture.

Brian

 

[tekno.mage]

I don't think your problems are to do with the type of lathe you are using (or for that matter the type of chuck/faceplate). I'd agree that getting hold of the Keith Rowley book (and DVD) already mentioned would be a big help - as would contacting your nearest turning club and seeing if you can get some "hands on" tuition. To get the type of catches you mention you are definitely doing something wrong - as has already been suggested you are probably presenting blunt tools at the wrong angle to the wood - you may also be trying to take too deep a cut and pushing the tool too aggresively into the wood. A sharp, correctly presented tool cuts eagerly without much effort required from the turner holding it (except to guide it to cut the shape they want).

Regarding the broken faceplate - it was probably a faulty or dropped casting in the first place - although depending on the nature of the catch you had, something would have to give and I guess your faceplate had to be the weakest link. Luckily if your lathe has a 3/4" x 16tpi spindle a replacement faceplate will be easy to obtain.

 

[YewTube]

I thought I'd have a go at cutting a thing-with-a-hole-in - maybe a pencil-holder or something

Jake,

Your problem is 100% technique and nothing to do with the lathe or chuck. The fact you can shear off a faceplate says everything. With the correct technique you should be able to do it by gluing the wood to a faceplate.

Pencil pots are usually end grain hollowed. This is a link to a video (see 10mins into it) showing how to hollow with a spindle gouge and scraper. Watch how he moves the handle of the gouge so as not to engage too much of the cutting edge.

http://youtu.be/MU0BWMLhjFk

Be patient and take it slowly until you build up confidence.

Remember all turning tools have a number of catches built in to them at the time of manufacture. You just have to keep using them until they are all used up.

Have fun.

Bill

 

[Walter Hall]

In agree with Bill. The lathe is not the worlds finest but neither is it the problem.

Given the recent publicity about woodturning safety following the untimely death of Joan Kelly it is worrying that people still think it is OK to buy an old lathe and dive straight in.

I would strongly advise that you get someone to teach you the basic tool techniques required to turn safely. At the very least have a read of the Keith Rowley book suggested by Chas and this overview of the health and safety risks.

 

[chill]

find a good professional turner and invest in a lesson or 2, this will be the best investment you make, your lathe may not be the best but should be adequate to get you well and truly bitten by the bug and eager to invest in better equipment, beware the slippery slope,