Lathe for miniature turning

[Takazeki]

Hi guys,

I'm looking for a lathe! I'm interested in creating miniature wheels from plastic materials with about 8mm OD and 4.5mm thick. I've been recommended the Unimat 4 but i'm still gathering more info to make sure this is the right lathe for me.

What do you think? Is it a good lathe for the job? Are there any other good alternatives until 500-600€?

Thanks!

oh.. & happy new year! :wink:

 

[John. B]

Well, I have a Chester DB7V which at the moment retails at £595 .05 which I would recommend. It is around your upper end of 600 euros.
Chester do cheaper ones so it may help looking at their website
www.chesteruk.net/ -

(I've no connection with Chester, they just have Good machines, Good service, and are near where I live)

 

[Mr Ed]

I would take a look at Axminster, they have quite a selection of smaller size engineering lathes;

http://www.axminster.co.uk/category-Lat ... 208209.htm

Cheers, Ed

 

[jasonB]

The Unimat will be fine for your needs, the shereline is also good for small work as is the old taig lathe.

You could also pick up a second hand jewlers collet lathe, maybe even a basic Pultra at that price

Don't forget to budget for tooling etc

Although the larger lathes will do the work they can be a bit over the top for small work and also need a larger work area. The Unimat can sit on a desk and be put away in a cupboard after use, thats what I used to do with my old Unimat 3.

Jason

 

[Takazeki]

Thanks a lot for your replies! I were almost decided to buy the Unimat but now i'm finding other great options at good prices too.

I don't have much experiencie with lathes, i assume any metal lathe will work fine with plastics right? What kind of tool should i choose to chamfer the edges of the wheels?

Regards

 

[jasonB]

You don't need the indexable carbide tipped tools that are the current trend. Just buy some 3/16" & 1/4" 5 & 6mm HSS tool blanks and grind to a suitable profile. A highish top rake will cut most plastics better than the angles on the tipped tools.

Jason

 

[Takazeki]

Ok Jason that's some useful information! Unimat has an accessory named "Top slide for taper turning", do you think it's also a good option to chamfer?

Regards

 

[jasonB]

Its an expensive tool just for cutting a chamfer at the size you are working at you just need a tool that is ground at 45degrees that can be fed into the work.

The topslide is still a useful tool cutting tapers and is usually easier to get accurate right to left cuts of specific length than trying to use the carrage. I would consider this a must have accesory.

Jason

 

[Takazeki]

Thanks again Jason, i understand what you're saying. I'm planning to do this wheels in semi-mass production so maybe the slide is a better option.

EdSutton suggested the Axminster lathe and honestly the quality seems very good and so does the specs. Plus the price is a bit cheaper than the Unimat which gives me some room for the tools. What do you think about the following order? I mean prices, quality, reliability and that..

Regards

 

[jasonB]

This lathe is sold by several companies for different amounts, I'm not sure what the axminster one is like but some need a good strip down, clean and rebuild before use. Otherwise it should do what you want. The chinese lathes are not finished to the same quality as the Austrian Emco of which I have had a unimat 3 and emcomat 8, I now have a Warco WM280VF which is chinese but the accuracy of what comes off it is good.

have a read of this supplier site http://www.arceurotrade.co.uk/Catalogue ... l-C1-Lathe

Don't get the tools you linked to as these are brazed tip carbide tools, they need a special (green) grit wheel to grind them and by the time you have ground the right top rake for plastic there won't be a lot of carbide left.

Jason

 

[Takazeki]

Oh so these are the famous chinese models! I'm a little concerned about the precision as i will have to work in decimals of mm's. From your experience do you think the Unimat is a good machine for the job? I've read very good feedback from this models, i'm just trying to be sure about my investment

By the way, i found a proxxon model here in Portugal a few days ago (PD230), can you tell me something about it? It's a bit more expensive but the description "precision lathe" attracted me!

Thanks for your time with my questions
Regards

 

[Rich]

Don't forget "warco"

Rich.

 

[jasonB]

I have not seen the Proxxon up close but they are similar to the Unimat for build quality but do seem quite expensive, £736GBP here.

The problem with a lot of the far eastern lathes is that what looks like the same lathe from one supplier may not be the same as one from another. The reason is they may use the same basic castings but they are then built to a budget which must affect the build quality. There are Chinese versions of the Unimat about as well and a lot of the accesories are interchangeable.

For example I could have bought my Warco for £330GBP less from another supplier but I went to Warco as their Build quality is said to be better. I'm happy with it and can easily work to 0.0005" or 0.01mm

If you want to se what can be done on a Unimat have a look at Gerald Wingroves work, all scratch built on a Unimat 3

Can I ask what the wheels will be used for?

Jason

 

[Takazeki]

That's some impressive work I've been looking at the warco mini-lathe and it seems quite a solid machine (also heavier than the Unimat). I noticed the warco has variable speed, do you think it's an important feature for the work? I looked into the datasheet and there's an accessory called vertical slide, i think it's same as the top slide from Unimat, is it?

The wheels i'm trying to create are to use in miniature skateboard replicas, that's why they must come out perfectly shaped/sized and be fairly resistant. I'm new to all these machining techniques but i'm a fast learner so i hope that with your help and some books i purchased i'll be able to do them

Right now i just have some doubts about the Unimat 4. It's lighter, has a weaker motor than most other lathes and also looks cheaper. I know this might be a wrong impression but this is what it looks to me when putting a Unimat and a Warco side to side (for example).

Thanks all (sorry any bad english!)
Regards

 

[jasonB]

Out of the two I would probably go for the Warco Mini lathe though both will do what you want.

The variable speed is useful as changing belts to alter speed can become time consuming if you are doing batch work.

The Warco comes complete with teh top slide, the vertical slide is to enable the lathe to be used like a small milling machine, the cutter goes in the chuck or collet, work fixed to vertical slide.

You should be able to find a national or at least European supplier of the mini lathe as they are sold all over the world (offten refered to as 7x12 or 7x14 lathe) with different badges and paint colours. Have a look at the mini-lathe site to get more info.

Jason

 

[Takazeki]

Thanks man, that site seems to cover almost everything about mini-lathes, perfect!

Ok so i have 2 final questions.. :lol: first, is the live center useful for my task? I mean, it looks like it will hold the rods better than the original dead center.. and second, is there any good tutorial or video that covers the basics of wheel's machining? I've been doing some draws and i think i have a fairly idea how to do give the shape, make the holes, etc. I'm also having help from a friend of mine with some experience with lathes. However, I'm wondering if i should make the hole across the 15cm rod first and then part off the wheels in sequence or first part off the wheels (already with the right size) and then make holes.

I know this question is not a buying advice anymore but i thought i should take my chance and ask

Cheers

 

[jasonB]

I don't think a live center will be of use to you.

Can you post a picture of your drawing or e-mail it to me by clicking my name, this will allow you to send a e-mail via the forum.

For simple wheels (disc with a hole in it) the sequence would be as follows

1.Put material in chuck with say 20mm protruding
2.Face off to give a square end
3.center drill
4.Drill to size (ream if it needs to actually run well)
5.Turn to diameter if the rod is not already 15mm
6.Chamfer edge
7.Part off two or three discs
8. repeat 1-7 as needed

If you intend to make a lot of these then make sure that the spindle bore of the lathe is able to take the diameter of your rod otherwise you will have to keep sawing off lengths to make say 10 wheels from and waste the bit that is left in the chuck.

There are a few other methods that can be used to speed up production of batch work an idea of the quantities you intend to make and the drawing would help.

Jason

 

[Mr Ed]

If you intend to make a lot of these then make sure that the spindle bore of the lathe is able to take the diameter of your rod otherwise you will have to keep sawing off lengths to make say 10 wheels from and waste the bit that is left in the chuck.

Takazeki - this is excellent advise from Jason; my own lathe only has about 1/2" spindle bore and I end up wasting quite a bit of material when you add it all up.

Cheers, Ed

 

[Takazeki]

Well my draw (a sketch basically) is pretty simple and the idea behind it is pretty much like those 8 steps I'll post it later when i find it though.

Anyway, once again you cleared my doubts but i think there's one little issue with my wheels. I want to chamfer the edges on both sides of the wheel so it's still not clear to me how i would do that in say the left side of the wheel (looking in front of the lathe), the side where the rest of the rod stands. I feel like there's a very basic solution so i would probably discover that myself when i get the machine and the materials..

The wheels will have a OD of 7.8mm (or even less) so i'm also wondering if a 10mm diam. rod is enough or not! By the way, should i also include a fixed steady in my buy list to help the drilling?

All the best
Taka

 

[jasonB]

There are several options for chamfering both sides

1. go half way with the parting tool, withdraw, chamfer, finish parting. This will be slow if there are a lot to make.

2. Machine as the list 1-7. When you have machined a batch put a mandrel (home made "jig" to lold wheel by the hole) in the chuck, fix wheel to this and chamfer. Again very slow.

3. Grind a special tool that will do three things at the same time. Basically a parting tool that has two edges which will cut the chamfer just as the parting cut is completed. Very quick and saves having to do the facing cut and a lot of tool changing. A refinement of this would be to have this tool in a rear rool post and the tool to turn the 10mm down to 7.8mm in the standard tool holder, that way you won't need to change any tools. This would be the fastest method and give the most repeatable results short of a CNC machine :wink:

The fixed steady won't be needed for what you want to do.

10mm rod will be OK, what type of plastic are you thinking of using, some turn better than others

Jason