I'm not a model engineer.

I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.

I want to cut out of it 3 pieces 15mm long.

I don't think I have much option than marking it out as best I can and 
using a hand/hacksaw.

Unless anyone knows of a more ingenious way that I could knock-up.

"Rich"  wrote in message 
news:6g0t3dFdjldpU1@mid.individual.net...
> I'm not a model engineer.
>
> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
>
> I want to cut out of it 3 pieces 15mm long.
>
> I don't think I have much option than marking it out as best I can and 
> using a hand/hacksaw.
>
> Unless anyone knows of a more ingenious way that I could knock-up.

Actually, I wonder if I can put the tube on a flat surface end down (of 
course). I cut out a 15mm high block of wood. Then I get my juniour 
hacksaw and rest the blade on the wood block. Then cut, every so ofter 
turning the tube untill I've cut through it all.

That's my best idea.

On or around Thu, 7 Aug 2008 19:37:51 +0100, "Rich" 
enlightened us thusly:

>
>"Rich"  wrote in message 
>news:6g0t3dFdjldpU1@mid.individual.net...
>> I'm not a model engineer.
>>
>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
>>
>> I want to cut out of it 3 pieces 15mm long.
>>
>> I don't think I have much option than marking it out as best I can and 
>> using a hand/hacksaw.
>>
>> Unless anyone knows of a more ingenious way that I could knock-up.
>
>Actually, I wonder if I can put the tube on a flat surface end down (of 
>course). I cut out a 15mm high block of wood. Then I get my juniour 
>hacksaw and rest the blade on the wood block. Then cut, every so ofter 
>turning the tube untill I've cut through it all.
>
>That's my best idea. 

bandsaw, I'd think, if you know of one big enough.  It depends on what
accuracy you want.
-- 
Austin Shackles.  www.ddol-las.net  my opinions are just that
Travel The Galaxy!  Meet Fascinating Life Forms...
------------------------------------------------\   
   >>  http://www.schlockmercenary.com/  <<      \  ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!

"Austin Shackles"  wrote
in message news:vqjm94dmmta23pgk1bojrf7hrkekilo1vg@4ax.com...
> On or around Thu, 7 Aug 2008 19:37:51 +0100, "Rich" 
> enlightened us thusly:
>
>>
>>"Rich"  wrote in message
>>news:6g0t3dFdjldpU1@mid.individual.net...
>>> I'm not a model engineer.
>>>
>>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic
>>> tube.
>>>
>>> I want to cut out of it 3 pieces 15mm long.
>>>
>>> I don't think I have much option than marking it out as best I can
>>> and
>>> using a hand/hacksaw.
>>>
>>> Unless anyone knows of a more ingenious way that I could knock-up.
>>
>>Actually, I wonder if I can put the tube on a flat surface end down
>>(of
>>course). I cut out a 15mm high block of wood. Then I get my juniour
>>hacksaw and rest the blade on the wood block. Then cut, every so ofter
>>turning the tube untill I've cut through it all.
>>
>>That's my best idea.
>
> bandsaw, I'd think, if you know of one big enough.  It depends on what
> accuracy you want.
> -- 

I think if I am prepared to spend a little money a tile cutter has been
known to work:

http://www.screwfix.com/prods/83636/Power-Tools/Tile-Saws/Titan-SF180T1-600W-Tile-Cutter;jsessionid=YZ1IE2A5ZPKEACSTHZOCFFY

>>>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic
>>>> tube.
>>>>
>>>> I want to cut out of it 3 pieces 15mm long.
>>>>

>>>Actually, I wonder if I can put the tube on a flat surface end down
>>>(of
>>>course). I cut out a 15mm high block of wood. Then I get my juniour
>>>hacksaw and rest the blade on the wood block. Then cut, every so ofter
>>>turning the tube untill I've cut through it all.
>>>
With those dimensions I'd use a grown up hacksaw rather than a junior. Two 
15 mm blocks, one each end of the blade to set the height, connected 
together in a bigger jig which supports the frame and holds the whole lot 
parallel to your flat surface. Or just make a hacksaw-shaped "frame" in 15 
mm timber / ply and screw a hacksaw blade to it.

The other way to cut acrylic sheet is to scribe and snap. With only 3 mm 
wall you could perhaps score a sharp V-groove almost all of the way through 
with a suitable tool supported at the right height by the same sort of 
method. I think I'd try to clamp the tube down to your base plate perhaps 
with a length of studding. You could cut a 200 mm dia circle in (say) 18 mm 
plywood to fit the bore, and screw/glue that to the baseboard to stop the 
tube moving around when you are cutting.

Rich Wrote: 
> I'm not a model engineer.
> 
> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
> 
> I want to cut out of it 3 pieces 15mm long.
> 
> I don't think I have much option than marking it out as best I can and
> using a hand/hacksaw.
> 
> Unless anyone knows of a more ingenious way that I could knock-up.

Make a hand lathe.

Use two rollers (broom stick tube will work) mounted in blocks and
locate the tube on those with a keep block at each end.

Use a ground bit of hacksaw in a block as the tool. If you support this
between two guides, so much the better.

press the tool against the tube with one hand and rotate the tube with
the other.


-- 
rsss
------------------------------------------------------------------------
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View this thread: http://www.rcgroups.com/forums/showthread.php?t=905590

rsss wrote:
> Rich Wrote: 
> 
>>I'm not a model engineer.
>>
>>I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
>>
>>I want to cut out of it 3 pieces 15mm long.
>>
>>I don't think I have much option than marking it out as best I can and
>>using a hand/hacksaw.
>>
>>Unless anyone knows of a more ingenious way that I could knock-up.
> 
> 
> Make a hand lathe.
> 
> Use two rollers (broom stick tube will work) mounted in blocks and
> locate the tube on those with a keep block at each end.
> 
> Use a ground bit of hacksaw in a block as the tool. If you support this
> between two guides, so much the better.
> 
> press the tool against the tube with one hand and rotate the tube with
> the other.
> 
> 
  Drop around to a machine shop with a box of donuts, or other 
appropratie local treat in hand, and ask the guy there if you could get 
a job done quickly.

  Offer to pay cash, too. If he takes the cash, so be it, but, in my 
experience, small jobs that take less than a few minutes, and are 
offered to be payed for (and do expect to pay, hoping otherwise!) are 
often gratis. The treats are for a thank you!

  Or hook up with someone local that has a lathe.

  I'd estimate the job at about 6 minutes, including finding the tooling 
I'd need.

  I like the home brewed lathe idea, but to work well will require 
rather more work than several alternatives.

  Low tech. Wrap a straight edged piece of paper around the tube to get 
a parallel set of lines.
  Aquire a hobby razor saw. Cut around the tube, a bit at a time, then 
finish the rings on a sheet of abrasive paper taped to a flat surface.

  If surface finish is not required to be anything special, a wood 
bandsaw will do the job nicely. Just need to set up a quickie jig to 
hold the tub e in alignment during the traverse across the saw blade.

  Cheers
    Trev

"rsss"  wrote in message 
news:rsss.3dtikn@rcgroups.com...
>
> Rich Wrote:
>> I'm not a model engineer.
>>
>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
>>
>> I want to cut out of it 3 pieces 15mm long.
>>
>> I don't think I have much option than marking it out as best I can and
>> using a hand/hacksaw.
>>
>> Unless anyone knows of a more ingenious way that I could knock-up.
>
> Make a hand lathe.
>
> Use two rollers (broom stick tube will work) mounted in blocks and
> locate the tube on those with a keep block at each end.
>
> Use a ground bit of hacksaw in a block as the tool. If you support this
> between two guides, so much the better.
>
> press the tool against the tube with one hand and rotate the tube with
> the other.


Yes, using two rollers on which to rest the tube is good.

If I made the spacing between the rollers variable then I could accommodate 
different diameter tube.

"Richard"  wrote in message
news:6g5j14Feb90eU1@mid.individual.net...
>
> "rsss"  wrote in message
> news:rsss.3dtikn@rcgroups.com...
>>
>> Rich Wrote:
>>> I'm not a model engineer.
>>>
>>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
>>>
>>> I want to cut out of it 3 pieces 15mm long.
>>>
>>> I don't think I have much option than marking it out as best I can and
>>> using a hand/hacksaw.
>>>
>>> Unless anyone knows of a more ingenious way that I could knock-up.
>>
>> Make a hand lathe.
>>
>> Use two rollers (broom stick tube will work) mounted in blocks and
>> locate the tube on those with a keep block at each end.
>>
>> Use a ground bit of hacksaw in a block as the tool. If you support this
>> between two guides, so much the better.
>>
>> press the tool against the tube with one hand and rotate the tube with
>> the other.
>
>
> Yes, using two rollers on which to rest the tube is good.
>
> If I made the spacing between the rollers variable then I could
> accommodate different diameter tube.


Okay my design:

I can get acrylic tube in 1m lengths.

I have a wooden baseboard 500mm in length say 200mm wide.

On each end, is a strip of wood with U shaped holes on the top edge evenly
spaced. These strips hold the bottom rollers.

Two strips of wood, one on each end, point upwards and are employed to hold
another two strips of wood with U shaped holes like the ones described above
for the botton rollers.

So, the acrylic tube is held in place by 4 rollers, two above, two below.

So, I first select the roller spacing appropriate to the tube diameter,  and
drop the bottom rollers into the end "bearings".

I use the same spacings for the top rollers and I manage to lock the top set
to the two uprights. Therefore the tube is "held" by the rollers.

One of the rollers has a handle on, so it can be turned. That makes the tube
turn.

A cutting tool is mounted in the top and gravity is used so it presses on
the tube. Or springs used to maintain pressure. Or one person turns,
(wife, girlfriend, offspring, passing member of the public). Another
presses a tool against the work.

"Richard"  wrote in message 
news:6g5lmbFefl3fU1@mid.individual.net...
>
> "Richard"  wrote in message
> news:6g5j14Feb90eU1@mid.individual.net...
>>
>> "rsss"  wrote in message
>> news:rsss.3dtikn@rcgroups.com...
>>>
>>> Rich Wrote:
>>>> I'm not a model engineer.
>>>>
>>>> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic 
>>>> tube.
>>>>
>>>> I want to cut out of it 3 pieces 15mm long.
>>>>
>>>> I don't think I have much option than marking it out as best I can 
>>>> and
>>>> using a hand/hacksaw.
>>>>
>>>> Unless anyone knows of a more ingenious way that I could knock-up.
>>>
>>> Make a hand lathe.
>>>
>>> Use two rollers (broom stick tube will work) mounted in blocks and
>>> locate the tube on those with a keep block at each end.
>>>
>>> Use a ground bit of hacksaw in a block as the tool. If you support 
>>> this
>>> between two guides, so much the better.
>>>
>>> press the tool against the tube with one hand and rotate the tube 
>>> with
>>> the other.
>>
>>
>> Yes, using two rollers on which to rest the tube is good.
>>
>> If I made the spacing between the rollers variable then I could
>> accommodate different diameter tube.
>
>
> Okay my design:
>
> I can get acrylic tube in 1m lengths.
>
> I have a wooden baseboard 500mm in length say 200mm wide.
>
> On each end, is a strip of wood with U shaped holes on the top edge 
> evenly
> spaced. These strips hold the bottom rollers.
>
> Two strips of wood, one on each end, point upwards and are employed to 
> hold
> another two strips of wood with U shaped holes like the ones described 
> above
> for the botton rollers.
>
> So, the acrylic tube is held in place by 4 rollers, two above, two 
> below.
>
> So, I first select the roller spacing appropriate to the tube 
> diameter,  and
> drop the bottom rollers into the end "bearings".
>
> I use the same spacings for the top rollers and I manage to lock the 
> top set
> to the two uprights. Therefore the tube is "held" by the rollers.
>
> One of the rollers has a handle on, so it can be turned. That makes 
> the tube
> turn.
>
> A cutting tool is mounted in the top and gravity is used so it presses 
> on
> the tube. Or springs used to maintain pressure. Or one person turns,
> (wife, girlfriend, offspring, passing member of the public). Another
> presses a tool against the work.

Or, it might be simpler to have two cross-shaped end pieces used in a 
system to lock the tube into a kind of "cage". Then turn the cage + 
tube. I bet that is simpler.

Rich wrote:
> I'm not a model engineer.
> 
> I have a 150mm long, 3mm thick-wall, 200mm dia extruded acrylic tube.
> 
> I want to cut out of it 3 pieces 15mm long.
> 
> I don't think I have much option than marking it out as best I can and 
> using a hand/hacksaw.

I use acrylic tube often at work. have tried a few ways with machine - 
generally it snags and cracks just as you finish the cut, especially 
with thinner wall. Resting the tube on rollers tends to mar the tube 
surface as the ever-present workshop grit gets ground in repeatedly.

The best way I've found is:
- wrap sheet of paper around the tube and mark along the edge.
- rest tube on an open vice or soft mat
- cut around with a hacksaw, turning to keep blade close to tangential 
to the tube. If the plastic melts, spit or water reduces the friction. 
If you get cracks, fit a plug - the added bonus is you can then turn 
down the cut edge on the lathe with the plug fitted.
- file edge fairly square, then with wet&dry paper stuck on a flat surface.
- to get a clear surface on the acrylic, buff extremely lightly with 
cotton mop wheel and brown polishing compound. A cloth and brass polish 
works at a pinch.

hth
Guy