Results 1 to 13 of 13
  1. #1
    Join Date
    May 2009
    Location
    Townsville, Nth Qld
    Posts
    3

    Default Best way to round aluminium bar corners

    I have some 30 x 3mm aluminium bar, and would like to shape the ends of the bar with 15mm radius curves on the flat surface, so the ends are nicely rounded in a semicircular shape. I can cut them to approximate shape with a hacksaw working on tangents of the curve, but want to have a nice smooth curve.

    I understand that aluminium will clog up a linishing belt or a belt sander, bench grinder wheels and some files.

    Not being a metal worker, I would welcome any suggestions
    regards,

    Dengy

  2. #2
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

    Default

    How many you have to do?

    Turn up some 30mm dia discs say 10mm thick. clamp one either side of the bar. File until you rub the steel. How badly the file clogs depends on the aluminium and how new your file is. Some chalk rubbed on the file after each clean can help. I use a spray of WD40.

    (works better if you have a hole in the bar so you can use a bolt, but you cant always have everything)

    Stuart

  3. #3
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    Round over router bit in a router table
    Rub wax on the corner.
    Practice
    Watch out for the shards they are razor sharp.
    Whoops I realise you want 15mm, could be a hard bit to find, 1/2" will get you a fair way there.

    You can sand ally on a linisher (I do it all the time), use a new belt, gentle strokes, keep the belt clean by applying a piece of PVC pipe to the belt.
    Practice first
    Grinding some chalk on the belt is supposed to work but I find it just makes a mess.

  4. #4
    Join Date
    May 2009
    Location
    Townsville, Nth Qld
    Posts
    3

    Default

    Thanks for sharing this experience. BobL. I will head over to my son in law's shed and give it a go.
    Do you put the flat edge of the PVC on the belt to clean it, or just the lay the pipe across it so the curved surface is against the belt, or doesn't it matter?
    regards,

    Dengy

  5. #5
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Quote Originally Posted by Dengue View Post
    I have some 30 x 3mm aluminium bar, and would like to shape the ends of the bar with 15mm radius curves on the flat surface,
    I'm a little confused, perhaps you can clarify some dimensions... is that 30mm diameter bar?

    Where does the 3mm dimension come into it?

    When you say the radius curves on the flat surface? Do you mean the curve is only in one plane? Or is the end like a half sphere?

    A picture or sketch would make it a bit clearer.

    Ray

  6. #6
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    It's 30x3 flat bar.

    The other simple one is a flap disc in an angle grinder. Trim the end to an approximate radius and then use the flap disc to blend.

    Michael

  7. #7
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Quote Originally Posted by Michael G View Post
    It's 30x3 flat bar.

    The other simple one is a flap disc in an angle grinder. Trim the end to an approximate radius and then use the flap disc to blend.

    Michael
    That all makes sense now... How accurate? or is it just for visual effect?

    If it's just for visual effect, find something 30mm diameter, and use it as a template to scribe a line on the aluminium, then roughly chop the majority of the waste with an angle grinder and thin cut off wheel, then finish sanding to the line in a disk sander, or linisher.

    Angle grinders don't like aluminium generally speaking, but small cuts like this should be no problem.

    Ray

  8. #8
    Join Date
    May 2009
    Location
    Townsville, Nth Qld
    Posts
    3

    Default

    Thanks for your input everyone, very much appreciated. I should have clarified above, the profile is more elliptical than semi-circular.

    Following on from the suggestions above, I drew the required profile on the flat ends of the aluminium bar using a cardboard template, then chopped it with a 1mm disc on a 4" angle grinder to a rough approximation of the required shape, and did the final shaping on the linishing wheel. Used BobL's suggestion of a PVC pipe to keep the linishing belt clean, worked perfectly.

    Very pleased with the result, having done a practice run and taking it slow and easy, frequently checking against the cardboard template of the profile
    regards,

    Dengy

  9. #9
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    Quote Originally Posted by Dengue View Post
    Thanks for your input everyone, very much appreciated. I should have clarified above, the profile is more elliptical than semi-circular.

    I drew the required profile on the flat ends of the aluminium bar using a cardboard template, then chopped it with a 1mm disc on a 4" angle grinder to a rough approximation of the required shape, and did the final shaping on the linishing wheel. Used BobL's suggestion of a PVC pipe to keep the linishing belt clean, worked perfectly.

    Very pleased with the result, having done a practice run and taking it slow and easy, frequently checking against the cardboard template of the profile


    Good to hear it's working.

    Tip, clamp 2 or 3 or more of the bars together and do them in on go, the larger area will give you more control and reduce the chances of sanding a flat spot.

  10. #10
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    The absolute best way to prevent ally clogging linisher belts, flap discs, grinding wheels and cutoff discs is candle wax.
    simply set your linisher, angle grinder or sander going and then apply candle wax to the wheel or belt.
    I am a boilermaker who has worked extensively with ally and that is what I use to this day. In fact, I will not touch a tool to ally without waxing it first with the exception of TCT saw blades and carbide burrs. I use metho sprayed on for the former and CRC/WD40 for the latter. Either of these work well for bandsaws and jigsaws as well, just remember to clean off the CRC/WD40 if you are welding the component. If you are sanding finer than say 80 grit then use velvet soap, (slightly moist is best, but dry works too).
    I would not generally use finer than a 60 grit flap disc with 40 being my preference.
    One final word of caution. Blow out sanders and grinders with compressed air on a regular basis. Ally dust penetrates everywhere and you do not want to be hanging onto a grinder that becomes a jet engine complete with flames exiting the vents, (yes, I have seen it happen and no, his undies did not survive the encounter).

  11. #11
    Join Date
    May 2009
    Location
    Townsville, Nth Qld
    Posts
    3

    Default

    Thanks for this valuable information, Karl. Where is the best place to get non scented candles?

    As I'm a non-metal worker, can you pease tell me what are carbide burrs?

    Also, is metho sprayed around a drop saw with TCT teeth safe, on account of the sparks generated inside the saw with the brushes etc.?
    regards,

    Dengy

  12. #12
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    Quote Originally Posted by Karl Robbers View Post
    The absolute best way to prevent ally clogging linisher belts, flap discs, grinding wheels and cutoff discs is candle wax.
    simply set your linisher, angle grinder or sander going and then apply candle wax to the wheel or belt.
    I am a boilermaker who has worked extensively with ally and that is what I use to this day. In fact, I will not touch a tool to ally without waxing it first with the exception of TCT saw blades and carbide burrs. I use metho sprayed on for the former and CRC/WD40 for the latter. Either of these work well for bandsaws and jigsaws as well, just remember to clean off the CRC/WD40 if you are welding the component. If you are sanding finer than say 80 grit then use velvet soap, (slightly moist is best, but dry works too).
    Good infö there Karl.

    The tip for using soap on fine sanding belts for ally sounds like a good one for ally, I'll tuck that one away for future reference.

    I found hard wax works a bit better than candle wax as candle was is a bit soft and melts too quickly and gets flung off high speed tools.
    I don't know where to get hard wax, I just get it from my ally working BIL
    I use metho sometimes in the way you indicated but as I found I am restricted to delivering it with a squirt bottle and that is not easy if both hards are needed on the tool so I tend to use wax on CT tools as well. One way to to get continual wax delivered to on the cutting edge is to rub the cut line or surface with wax,
    I do use metho when using a drill press (one hand is usually free to hold a squirt bottle) and also on lathe work, and also when using taps and dies - works great.

  13. #13
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Quote Originally Posted by Dengue View Post
    Thanks for this valuable information, Karl. Where is the best place to get non scented candles?

    As I'm a non-metal worker, can you pease tell me what are carbide burrs?

    Also, is metho sprayed around a drop saw with TCT teeth safe, on account of the sparks generated inside the saw with the brushes etc.?
    Carbide burrs are tools used in die grinders instead of grinding stones. They are available in a range of shapes and sizes with cylindrical, ball and christmas tree shapes the most common. There are from memory 3 basic tooth styles used on burrs ranging from a coarse single cut tooth designed for fibreglass through a less aggressive single cut tooth aimed at ally and other soft metals then progressing to a finer double cut tooth style more in keeping with steel and cast iron usage. In thinking about it just then, I reckon they could have some applications in the woodworking field too.
    Metho is quite safe around saws due to the fact that when sprayed on the blade, (we generally use a squirt bottle and give a couple of squirts with the saw running, this is generally sufficient to prevent clogging of the saw teeth), it is largely contained by the guard and doesn't reach the brushes etc. I have never witnessed or heard of a flash or fire caused by metho. Unless you leave it next to where you are welding, but that's another story in itself.
    We generally aren't too fussy where we get our candles, (scented work fine too and probably provide a calming aura in one's workshop into the bargain . Wherever candles are on sale cheaply is where we source them.
    Using the velvet soap and rotary sander method with say 80 then 180 then 400 grit paper, you can almost get a polish finish provided you use plenty of soap and particularly with the 400 grit, change the paper when it smears the ally rather than cuts. A quick buff with a lambswool mop and cutting compound will see a beautiful polished finish produced.
    Hard wax may possbly be better as far as fling off goes, but due to the availability and pricing of candles, we have stuck to them.

Similar Threads

  1. Large Aluminium round for sale at my local
    By jhovel in forum METALWORK GENERAL
    Replies: 1
    Last Post: 29th Nov 2011, 11:59 PM
  2. Radius Corners
    By Knocker in forum METALWORK GENERAL
    Replies: 2
    Last Post: 26th Nov 2007, 12:45 AM
  3. How do I Roll Aluminium round bar?
    By Owen Pooley in forum METALWORK GENERAL
    Replies: 19
    Last Post: 29th Mar 2006, 02:13 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •