Proxxon Mini Lathe DB-250 - Opinions/assessments/recommendations?

[rtropp]

Does anyone know of any accessories for the db250 that will provide center support? I believe I have seen them for metal lathes but not for wood lathes.

I was hoping to find something that would provide more support (rigidity)when shaping longer masts.

 

Thanks,

Richard

[wefalck]

I don't think they do a fixed steady. However, it is not so difficult to make one yourself. In order not to leave marks on the wood, I would use a thick and stiff cardboard disc into which a close-fitting hole has been drilled/punched. This cardboard can be held by three scews with washers against a piece of plywood into which a larger hole, say of 1 cm diameter, has been drilled. The three-screw-plus-washers-arrangement allows you to center the steady on the work. The plywood can be held upright on the bed of the lathe with a small angle iron that is clamped down onto the T-slot.

 

wefalck

[pompey2]

Enjoying this thread.

I have a few questions and observations.

I have a through bore headstock which is great for longer lengths but be warned thinner material can somtimes result in a 'whip' which will break the material sticking out the back.

i generall go for a three jaw chuck (four jaw is really fo centering odd shapes) i centre drill the other end and use a live centre, Interested to hear others choice?

Unless using the original stock diameter I dont find exact centering a big issue, provided i finish turn in one setup it will all come out concentric.

I'm interested in how small a diameter people find they can turn too. I have done to about 2mm but generall go to sandpaper before that.

I found a great tool rest online, A stainless 'T' bar the rest part being round seems to improve the smooth chisel sliding.

The other thing that I would like to hear is how people deal with long lengths, turn a bit and pull stock through or try in one hit?

 

Thanks

Nick

[tkay11]

Thanks for the info, Nick. Could you give a link to the tool rest that you found online?

 

Tony

[pompey2]

Tony

 

here is the 'stem', search the site for the cross bars etc

 

http://www.turners-retreat.co.uk/1-tool-rest-stem

 

Nick

[tkay11]

That's great. Thanks, Nick.

 

Tony

[rtropp]

Welfalk,

Great tip,

 

I believe I already have what I need to try it.

 

Thanks

Richard

[michael mott]

 

but intentional. It is tedious to center stuff, e.g. with a feeler gauge,

I find that most self centering chucks have enough slop in them that they are fine if you can do all the work in one setup, then everything is concentric. If however you have to flip it around in the chuck then getting it perfectly re centered you need to use a four jaw chuck I use a dial gauge to center the work. it is very easy then to make the fine adjustments.

 

Michael

[WackoWolf]

What Michael said is right on. The 4 jaw chuck would be better and setting it up isn't as hard as it sounds.

[maggsl_01]

Hi all...

 

I bought the DB 250 Lathe (110 Euros) and I am really grateful to myself (and my wife who said "OK"  ) that I did. The work goes so fine with this little machine - although there is NO 5mm-insert available. I use some tape to get the 5mm-masts into the 6mm-hole. The easy way - but it works.

 

I can recommend this machine for our modelling purpose.

 

Cheerio

 

Max

[wefalck]

What type of collets does it actually use ? PROXXON sells several types of (proprietary) collets separately. Otherwise, you can get a light plastic 4-jaw chuck or a metal 3-jaw chuck that allow you to chuck-up larger diameter parts.

 

wefalck 

[tkay11]

They're 2, 3, 4, 6, 8 and 10mm with my Proxxon DB250 wood lathe.

 

The only problem I've had with it so far, is that the tailstock is about 0.2mm away from dead centre. I'm trying to fix it with some shims. So far a paper shim has worked to fix the vertical discrepancy, but there's still a lateral discrepancy I'm trying to fix. Unfortunately it would mean shaving a bit off the tailstock sliding base and I can't think of another way round it yet.

 

Part of the problem is that the way the tailstock is made means that there is some freedom of movement either of the tailstock or of the drill chuck, so the combination means that drilling an accurate 0.5mm or 1mm hole in a rod with diameter of 3.7mm is next to impossible for me at the moment.

 

Tony

Edited January 27, 2014 by tkay11

[Q A's Revenge]

Thanks for the info, Nick. Could you give a link to the tool rest that you found online?

 

Tony

Robert Sorby make them as well.

 

http://www.robert-sorby.co.uk/modulartoolrestsystem.htm

[tkay11]

Thanks, QA. I'll look into it.

 

Tony

[wefalck]

… Part of the problem is that the way the tailstock is made means that there is some freedom of movement either of the tailstock or of the drill chuck, so the combination means that drilling an accurate 0.5mm or 1mm hole in a rod with diameter of 3.7mm is next to impossible for me at the moment...

Well, wood lathes are acctually not really designed for this kind of centre-drilling, that's the domain of metal lathes, even when it is done into wood. The purpose of a wood-lathe is rough centre a piece of wood and then to work it down with chisels. That's why wood-lathes typically are built much more simple (and cheaper). By the same token, a wood-lathe tailstock-barrel (or least the one of the DB250) are not meant to work under load, they are designed to be set and then clamped tight. To work under load, the tailstock bore would have to be ground carefully in line with the headstock to a sliding fit for the barrel - at the price of the lathe this would be impossible.

However, scraping-in (the workmanship method) or filing-in (the amateur's way - I did it as well …) of tailstocks to the bed is possible, if there is enough 'meat'.

 

wefalck

[tkay11]

That's as I expected, Wefalck -- and thanks for the usual thoughtful reply that you give to such questions. I was saying to myself that I shouldn't expect that sort of accurate work on the wood lathe.

 

All the same, I like challenges, and so I was trying to think of various tricks around the problem. I have at least got the accuracy down to about 0.1mm of dead centre (by pressing on the chuck with my hand and only allowing the drill bit to go in about 6mm at a time), but it remains possible to notice that the hole is not quite centred if it is looked at carefully.

 

By the way, what is meant by 'scraping-in'? I figure 'filing' means filing down the edge of the tailstock base. I had thought of that, but then thought I might well make the problem worse if I didn't have an accurate enough set-up to file it down accurately and totally parallel with the holding groove in the bed.

 

Tony

[RMC]

I bought one at BE's suggestion -and the extra bed.  I'm very happy with it. The longer bed enables pieces to be turned up to about 300-350 mm in length, depending on the thickness of the material.  One limitation is that the chuck will only handle material up to about 11mm in diameter.

 

RMC

[wefalck]

Tony, hand-scraping is an old-time, well, art of precision-fitting of machine surfaces. With a chisel-like tool minute amounts of metal are removed until a perfect fit or match has been achieved. More details e.g. here: http://en.wikipedia.org/wiki/Hand_scraper. The 'fitters' at the same time tried to achieve a pleasing looking surface. Today with CNC-precision grinding this craft is only needed for repair or restoration work. I am only a self-taught evening-mechanic, so I don't really master it and rather use a file  

 

I don't have such lathe, so I don't know how the tailstock is actually constructed. Looking at the catalogue picture, I think there is a simple bore going through the tailstock; the barrel presumably is plain in the front part and has a thread cut into the rear part; the brass nut that runs in a slot of the tailstock moves the barrel in and out; the barrel also has a key cut into the top surface; a thumb-screw on top of the tailstock prevents the barrel from turning and also locks it when set. Am I right ? If could post a picture of the disassembled tailstock, perhaps I could give you some ideas how to reduce the side- and end-play of the barrel. Do you have a pillar-drill ?

 

wefalck

[tkay11]

Thanks, Welfalck. You are quite right about the construction. I attach a photo as requested.

 

When I say that there is slight play of tailstock and chuck, this is even after the holding screw is tightened.

 

I don't have a pillar drill, but I have an ordinary drill stand for the standard electric drill. The stand is not of the highest accuracy, but once I have a drill bit positioned on a piece it at least drills vertically.

 

Other than the paper I have been using as a shim, I have brass shim sheets of .001", .002", .003" and .005". I could see if one would fit on one side of the tailstock holder.

 

Thanks for the link about the scraper!

 

Tony

 

Edited January 28, 2014 by tkay11

[tkay11]

Well, I have fiddled with adding brass shims, and I am totally surprised that a 0.05mm shim has fixed the problem.

 

I managed to squeeze it in on one side of the tailstock holder as shown in the photo, and this has not only reduced the play to almost nothing, but I am now hitting dead centre.

 

I might now exchange the paper shim underneath the holder for a brass shim of the same size (0.1mm) but possibly I'll wait a bit before doing this as I try to hold to the motto 'If it ain't broke, don't fix it'.

 

My estimate of 0.2 must have resulted from the distance of the holder from the end of the drill point -- thus increasing any angle of deviance.

 

Tony

 

[wefalck]

Yes, if it works for the time being, it may not be worth spending more time on it.

 

If I were to do something about the problems, I perhaps would modify the tailstock a long what is practice in other lathes (see drawing below): I would file a notch under the front of the tailstock barrel, so that I have a completely round section may be about 10 mm long. I then would make a thin saw cut along the centre of the barrel until perhaps half-way down to the notch for the brass nut. Next I would make a clamp (from aluminium, but some tough plastic, such PVC, or even wood would work) that fits tightly around the round section of the barrel. The clamp is slotted and can be tightened with (thumb-)screw just enough to give the tailstock runner a sliding fit in the barrel. The clamp can be used also instead of the thumbscrew on top of the barrel to lock the runner in position.

 

 

These modifications would likely change the need to shim the tailstock, so should be done first.

 

I may also file the nut a bit thinner and put a spring washer in front of it, but this would depend on how much end-play you have, when the runner is not locked.

 

wefalck

[tkay11]

Excellent suggestions, Wefalck, and highly doable! I like the idea of the spring washer, as well, as I was thinking about the play round the nut.

 

Thanks very much

 

Tony

[wefalck]

The simple tailstocks of my watchmaking lathes are designed that way ...

 

Obviously the DB250 was designed to keep manufacturing costs and, hence, retail prices low. Actually, the PROXXON guys are usually quite good in optimising usefulness, manufacturing quality and price. If one upgrades the design-specs, necessarily the prices go up. For the desing-spec of the simple wood-turning lathe, a mis-alignment of the order you described is largely irrelevant. Otherwise the design-guys probably would have come up with a solution as per my sketch right away.

 

Talking about (simple) modifications: it would be quite easy to convert the tailstock into a lever-action tailstock for drilling along the lines of e.g. the Taig/Peatool one. It needs a few strips of aluminium, a drill, a hacksaw, and a file to make such lever.

 

 

PROXXON uses standard stock materials to keep cost down. So I am sure that the tailstock runner is made from standard ground stock and you can replace it easily with material of the same dimensions. 

 

Sorry, I was getting carried away by ideas …

 

wefalck

Edited January 28, 2014 by wefalck

[tkay11]

That looks like a very nice project, Wefalck, but I think I'd need to come over to Paris to see your workshop and learn a bit more from you before taking such a job on!

 

I suppose the file would be needed to make the sliding mechanism with runner and grooves. What would defeat me, I think, is filing with that precision. Or maybe it's like ship modelling -- just start and learn by doing.

 

Tony

[wefalck]

It is quite amazing what skilled mechanics can do with a file (and time) … I am only self-taught, learned things by doing (and reading a few books).

 

For the lever-tailstock, no other modifications to the existing tailstock, but drilling a hole somewhere in the lower back of the upright part would be needed. From strips of aluminium as you would get in most DIY stores you can fashion the short link and the longer lever. One would need to somehow connect the existing tailstock runner to the lever. Is the runner solid or has it a bore in the back ? One can drill and tap (on the drill-stand) into the back of the runner (if it is not hardened, which I doubt), file (or bend) a U-shaped bracket from aluminium or plastic and connect the two by long screw. The U-shaped bracket would connect the lever through he screw to the tailstock barrel.

 

wefalck

[tkay11]

The runner is solid, so conceptually one could do the modification.

 

However, I'm going to stick with the current setup for the while since it is doing the job and I still have a long way to go in learning the basic skills in using the lathe. It took me months before I was happy in using my table saw, so I expect the same learning curve for even such a simple lathe!

 

Thanks, though, for all the ideas, Wefalck. Keep them coming -- they certainly spark the imagination!

 

Tony

[Q A's Revenge]

I have to say that, that "tailstock" is incredibly flimsy and if it's only 0.2mm out then it's far better than one might expect, especially for a wood turning lathe.

[tkay11]

Yes, QA, it does look flimsy, but it seems quite solid to me --  given that I don't expect the forces on it to be too great (and I'm not going to test it by clouting it with a 2lb hammer). I'm really pleased with the DB250. I had dithered for a while about getting a metal-turning lathe, but reasoned:

 

(a) that I was just working with wood.

 

( that the level of accuracy with wood would be quite sufficient -- especially given that a lot of modellers on this site use the DB250 and have very good results (in addition to being pleased with it themselves). I have seen lovely small pieces made with the DB250, and in addition many say it is very handy for working with masts -- even more so should I bother to buy an extra bed to extend it.

 

c) that a metal-turning lathe would be overkill for me. I can't see myself working with metal for quite a while. Furthermore, that although I could turn wood in the metal-working lathe, it would only be for work with small pieces, and work with masts would require me to return to my household drill. I am happy with shaping masts using my household drill setup, but have found the DB250 so much more convenient to set up and easier to use.

 

(d) A metal-turning lathe and all its accessories would be expensive. I only have a small budget for such things. £500 would be way above anything I could afford. I read that the affordable micro-lathes would have to have a lot of setting up. And the slightly larger afordable mini-lathes that  also require care in setting up but are less prone to issues with alignment would be out of my budget. Then I had a look at the cost of all the accessories and that really put me off.

 

I can foresee that one day I'll be interested in a metal-working lathe, but that will depend a little on the outcome of the lottery. In the meantime I'll have a lovely time learning wood turning skills with the DB250. I've already learned to appreciate the 4-jaw independent chuck and learned how to turn 4mm wheels from square stock. Great fun!

 

Tony

Edited January 28, 2014 by tkay11

[thomasl]

after reading this thread, thanks guys.   I'm sold on a DB250 with a bed extension   for my masks I need to make

let you know how it works out

[Per]

Something like the sensitive drill attachment for my watchmakers lathe would be useful. The runner slides in a sleeve that fits in the tailstock bore.

 

Per