Joining ali tube.

[J-G]

I've done a quick schematic to show the various parts of the lathe. I've omitted the Cross-slide detail to keep it clear. It is to scale at the size of the Osaki 300.

The Head-stock bore is the hole that goes through the head-stock to enable longer lengths of material to be held - usually for making batches of small parts.

I would recommend supporting the free end of your tube with a chamferred bung which is also supported by a revolving centre. These are not supplied as standard so you need to buy the revolving (or 'LIVE') centre and make a support bung - from alum/steel/delrin/wood - it doesn't really matter what material you use, it just needs to fit on the open end of the tube and have a centre-drilled hole in the tail-stock side.

Naturally, in use, the tail-stock/Live Centre will be pushed up to the Alum tube - I've separated them so you can see what I mean.

You might also consider the Warco WM 150 which has a more powerful 450W motor though a smaller bore (11mm) and is currently £30 cheaper than the Osaki. I do have first hand knowledge of Warco - I have one of their milling machines - and can recommend.

 

[ColeyS1]

Any chance we could get a little more detail of its application?

Sent from my SM-G900F using Tapatalk

 

[skipdiver]

Great info J-G, thanks. Funnily enough i was looking at the Warco last night and it's got £50 off at the moment.

Perhaps a picture or two would help with what i require.

 

[J-G]

Great info J-G, thanks. Funnily enough i was looking at the Warco last night and it's got £50 off at the moment.
Perhaps a picture or two would help with what i require.

I was going to suggest a visit to the Model Engineering Exhibition on until Sunday in Warwickshire but Warco aren't listed as attending. Their web-site does say they are !!! Confused? you will be! If you did want to drive what I estimate to be the 80+ miles to the Warwickshire Exhibition Centre, I'd be happy to meet up and give you a 'hands-on' guide of the Warco and Chester offerings and the many other general engineering suppliers that you will no doubt need to deal with once you have a lathe

The full details of the WM 150 spec., along with pictures, is at :
http://www.warco.co.uk/metal-lathes-met ... lathe.html

 

[skipdiver]

Thanks for that J-G, but i am working all weekend fulfilling an order. I will be using the last of the machined parts i bought in and will then have a while to sort out stuff before the next batch is due, so no hurry as yet. BTW, it's about 120-130 miles from here to there, dependant on route. My other half is from Rugby.

 

[J-G]

You're welcome, Steve. Sometimes opportunities are out of time.

I just did a quick 'Google Maps "Crow Flies" Measure' from WEC to Grimsby - that's why I put the '+'

 

[ED65]

The nearest stock size is 1 1/8", which is 28.8mm and is a tad too big.

Worth checking: is this the case with ali only?

I don't know the market at all for tubing or rod but if the insert could be another material you could expand your search to SS, plain steel, copper, brass, plastics maybe and of course wood.

If you have no choice but to stick to using the aluminium tube, at a 6" length you also don't need a lathe to do a small amount of turning-like tasks if you can rig up something with your power drill in a drill stand, or a pillar drill if you have one.

 

[MusicMan]

If you can't pull the tubes apart at all because of the cloth, I can't see how you will get the inner tube retracted into the outer tube. Could we have a pic?

You're in a bit of a quandary with lathe choice. I guess the method you are thinking of is to mount the tube in the headstock, pull out just over 6", support the end in a bung in the tailstock and turn down the tube then part it off. Not the easiest of operations in fact to get the tube centred accurately enough for this in a three-jaw chuck, so your accuracy will be limited. You could do it in a four jaw but there is extra setup time. Also, you have to get a lathe with a spindle hole big enough to to take a 28.8 mm tube. This pretty much rules out any micro lathe. Even my quite big Boley 4 would not do this. You are looking at something quite substantial and expensive. And you definitely want a power feed for the tool.

Possibly you would want to hold say 7" pieces in the three jaw (again with a bung at the tailstock end), turn down then part off. This would work well enough on a modest lathe but would waste material in the cutoff.

You could investigate centreless grinding, done by a third party as a service. The machine is fairly costly but once you have access to it, the process is very fast and will size the tube to great precision. There are services all over the place, e.g. https://www.westmidlandgrinding.co.uk/s ... -grinding/. I don't know the cost but expect it would be cheaper overall than an in-house lathe solution, because it would only take seconds to make one piece. You can probably get quite long lengths fed in at once, and cut them up yourself on a chop saw with metal cutting blade. The cheap Evolution chop saw would do it, but you do have to make a proper clamp to stop the tube rotating as it is cut. I suggest that you locate a centreless grinding service near you and go and talk to them.

Keith

 

[SteveF]

how about seat post shims (cycle) they make posts in different diameters as well
not sure what your paying and how long they need to be

i seem to remember being able to get in various sizes

Steve

 

[MusicMan]

An even simpler solution is to buy inner and outer tubes that are design to telescope and fit. In the sizes you mention there is

https://www.metals4u.co.uk/aluminium/c1 ... mm-(-1-14-)-od/p3057?showvat=true&gclid=EAIaIQobChMIhrLwz8z_1gIVIxbTCh3oRQhhEAQYASABEgJJV_D_BwE

Of course, I don't know the application or the tolerance that you need, but it's worth looking. Telescoping tubing is a very common need.

Keith

 

[skipdiver]

Thanks MusicMan, but i had already seen that and ruled it out. It is the wrong grade and gauge of ali.

I've been looking for months on and off and i have come to the conclusion that the way they are made now is the way forward, so unless i can buy the correct diameter tubing off the shelf, i think i am going to have to learn how to turn it on a lathe. If anyone knows if and where i could purchase 28mm 10g ali, i would love to know. The only stuff i can find is 1 1/8", which is about 28.6mm give or take. That 0.6 is my nemesis.

I know you can get 28mm copper but it would not be strong enough and look daft anyway. I think you can get 28mm stainless but again it wouldn't look right and in a thicker gauge is very expensive. I have even contemplated 28mm hardwood dowel, but i'm not sure how stable it would be. May get a length and try it.

 

[skipdiver]

Sorry, didn't see the earlier post from you about the practicalities using a lathe to do what i want to do. I think i may just look around for someone else to make these small pieces for me. My town is over-run with engineering firms. There are scores of them.

SteveF, again i had already considered that but ruled it out. The joint is a sliding one because there is no play in the mating tubes to pull them apart or screw them together. They have cloth riveted to them which makes it impossible. The short 6" piece slides inside one tube, they are brought together and then slid back into the mating tube, before they are fixed. I really ought to take some photos, but i got busy and forgot. Only just finished for the day, so i will do it in the morning. A solution is waiting to be found i'm sure.

 

[MusicMan]

Have you rejected the centreless grinding route, then?

Keith

 

[skipdiver]

Have you rejected the centreless grinding route, then?

Keith

No. It was the tubing you linked to that i had already seen and ruled out. I don't know what centreless grinding is to be honest, so am about to have a search on the net.

 

[skipdiver]

The nearest stock size is 1 1/8", which is 28.8mm and is a tad too big.

Worth checking: is this the case with ali only?

I don't know the market at all for tubing or rod but if the insert could be another material you could expand your search to SS, plain steel, copper, brass, plastics maybe and of course wood.

If you have no choice but to stick to using the aluminium tube, at a 6" length you also don't need a lathe to do a small amount of turning-like tasks if you can rig up something with your power drill in a drill stand, or a pillar drill if you have one.

That would be great, if i could rig something up myself, but not sure how to go about it. I did put a piece in a drill and tried sanding it down, but it was very dusty and time consuming. I have a pillar drill, so that may be a possibility. Ali is soft and i don't need to take much off the diameter.

 

[Jake]

This site lists what looks like true 20mm tube on the basis that it specifies either an imperial or metric OD (don't know if the grade works for you)

https://www.doremetals.co.uk/aluminium/tube/

 

[skipdiver]

Thanks Jake but again, already checked them out. They have an incredible range of sizes and gauges in imperial and metric, but alas, no 28mm, which is the size i want.

 

[Jake]

Ah, sorry brain fade after reading.

You've been through the tent pole analogy also (I feel like I also have,maybe your earlier thread)

http://rbjplastics.com/standard-profile ... ional.html

 

[skipdiver]

Yeah, looked at those too.

After much thought, i'm going to try some 28mm hardwood dowel and see how i get on with that. Stick to what you know, which in my case is wood.

 

[Jake]

Last idea I have is poke around on Alibaba and if you can stick a wanted ad up and see what comes out. I've only used it a few times but its worked out well each time, so if you can find someone offering machining services