Accurately drilled flat bar

[bigegg]

I'm looking for a source of flat bar with ACCURATELY spaced (as in +-0.5mm) holes along it.
Probably 1m x 50mm x 4mm but these dimensions not critical.

It's going to be a jig to make <something>.
The holes can be any diameter 1mm - 8mm (but preferably on the order of 4mm +-2mm)
I need a couple of lengths about 1m long to start
Need to have holes on the order of 100mm apart. (so could be 32mm/25mm/50mm)
Exact spacing doesn't matter, as long as they are all the same distance apart and the centres in line, to within the 0.5mm tolerance.
Needs to be cheap - I haven't priced up, but I'm guessing that CNC'd will be £££?
I'm hoping to pay something like £10 per meter
I don't think regularly punched railing bar is going to be accurate enough?
If the prototype works, I'll be wanting probably 50-100m a year - that *might* be worth getting CNCd?

last resort is for me to machine one to the tolerances I need - but I'm hoping someone can suggest an "off-the shelf" solution?

 

[Paul.]

Laser cutting, you will be surprised how cheap they are if buying a few of them

 

[Welderpaul]

Cheap AND accurate?

Laser cut them. Supposedly to 0.4mm accuracy. Cheap too.

 

[bigegg]

Cheap AND accurate?

I know. I know.

But "accurate" is relative...
I don't need them to a thou. Just "woodworking tolerance"

 

[WorkshopChris]

As above laser is the way to go but if you have to make a few, how about a jig?

A length of bar with your 3 accurately drilled holes.
Then drill the 1st hole in your 1m bar drop the jig on and put a dowel through 1st hole drill 2nd.
Then repeat dropping 2 dowels into the last 2 hole's till you get to the end.
Would keep it accurate and save the marking out.

 

[Spark plug]

As above laser is the way to go but if you have to make a few, how about a jig?

A length of bar with your 3 accurately drilled holes.
Then drill the 1st hole in your 1m bar drop the jig on and put a dowel through 1st hole drill 2nd.
Then repeat dropping 2 dowels into the last 2 hole's till you get to the end.
Would keep it accurate and save the marking out.

You could use this method and tack weld say 4 together on top of one another to increase productivity.

 

[knighty]

rule of thumb for laser cutting is you can;t make a hole that's thinner than the material you're going through...

so at 4mm thick the smallest hole you can go for is 4mm... but for accuracy you'll need to go bigger

I'd go for the 8mm holes if I were you, (if you get it laserd) gives the laser room to punch through the centre and then move around the outside of the hole :-)

 

[mike os]

For 2 I would have thought manual milling, once you want more laser or waterjet. .. water jet might require a drill run through ... but at the sizes you want so might laser if you want parallel sides

 

[bigegg]

As above laser is the way to go but if you have to make a few, how about a jig?

A length of bar with your 3 accurately drilled holes.
Then drill the 1st hole in your 1m bar drop the jig on and put a dowel through 1st hole drill 2nd.
Then repeat dropping 2 dowels into the last 2 hole's till you get to the end.
Would keep it accurate and save the marking out.

I just bought a joint genie dowel jig (very good, btw!) so this idea is a goer.
Ill get a quote for laser cutting tomorrow as well.
Thanks everyone!

 

[cianh91]

Rule of thumb on laser of not being able to go smaller than thickness is gone we regularly do it we do tons of 10mm with 6.5mm holes its down to the machine and programmer .
as said above you be very suprised how cheap it would be to get it lasered .
as for tollerance our lasers are quoted at within 0.02mm with proper set up never more than 0.2mm

 

[Agroshield]

I'm looking for a source of flat bar with ACCURATELY spaced (as in +-0.5mm) holes along it...

I'm hoping someone can suggest an "off-the shelf" solution?

If you want 100mm centres with 0.5mm accuracy, this is easily achievable with hand tools and a drill press.

The secret is in the marking out. Start with cold rolled stock. Blue it up with a marker pen. Scribe a line parallel to one edge with oddlegs calipers or woodworking mortice gauge or scriber and adjustable square. Use a sharp pair of dividers set to your desired hole spacing and step off arcs. Use a loupe or the +3 cheater lens from your welding mask and prick punch (1/8" tungsten) to mark hole centres. Centre punch (sharpened Hilti nail) prick punch marks. Drill on drill press with stub length or spotting drill.

Off the shelf? What about pegboard that is drilled with a regular grid of holes? What about perforated metal (even gauze or reinforcing mesh)? A piece of Unistrut? A piece of Dexion? A shelf upright from Ikea? A sash clamp bar? Perforated repair band from Toolstation? Long joist hanger or rafter strap? Buy some long pieces of Meccano and bolt together until desired length is achieved. Do you have any technical Lego?

 

[Kent]

I know. I know.

But "accurate" is relative...
I don't need them to a thou. Just "woodworking tolerance"

, bout quarter of an inch then

 

[bigegg]

, bout quarter of an inch then

Lol
I work to 1/32 of an inch...
1/64" for indoor work.

 

[slim_boy_fat]

, bout quarter of an inch then

Up here's it's known as " a jiner's thocthie".......

 

[penfold]

For 2 I would have thought manual milling, once you want more laser or waterjet. .. water jet might require a drill run through ... but at the sizes you want so might laser if you want parallel sides

I used to get components made using this technique cut from 10+12mm Hardox plate; self-piercing was not a problem, although there may be a minimum hole size, kerf was about half a mm IIRC.

 

[DAPPH]

, bout quarter of an inch then

Them as built this place appear to have excelled themselves & worked to the the nearest foot .

 

[Rocketman]

I'm looking for a source of flat bar with ACCURATELY spaced (as in +-0.5mm) holes along it.
Probably 1m x 50mm x 4mm but these dimensions not critical.

It's going to be a jig to make <something>.
The holes can be any diameter 1mm - 8mm (but preferably on the order of 4mm +-2mm)
I need a couple of lengths about 1m long to start
Need to have holes on the order of 100mm apart. (so could be 32mm/25mm/50mm)
Exact spacing doesn't matter, as long as they are all the same distance apart and the centres in line, to within the 0.5mm tolerance.
Needs to be cheap - I haven't priced up, but I'm guessing that CNC'd will be £££?
I'm hoping to pay something like £10 per meter
I don't think regularly punched railing bar is going to be accurate enough?
If the prototype works, I'll be wanting probably 50-100m a year - that *might* be worth getting CNCd?

last resort is for me to machine one to the tolerances I need - but I'm hoping someone can suggest an "off-the shelf" solution?

How I'm reading this is actually far tighter tolerance than you or others appreciate. Are we saying the very last hole position can't be more than 0.5mm out of position from the first hole. In other words the tolerance isn't stackable. How tight tolerance does the plate need to be to.

 

[Kent]

A good laser cutting place will tell you its possible to get things exactly as stated = if you require this the only Tollerance will be finish and that's pretty darn good. Up to. 12mm plate

 

[DAPPH]

Today I saw some roof truss & wall collar tie bars at a builders merchant , three rows of holes in a 50 mm wide xx 5 or 6 mm thick flat bar about a metre lone each , it might be worth looking if you take a digital caliper with you and some pegs .

 

[clift_d]

If it needs to be a pre-fab solution then maybe something like a Hilti MI-90 girder would work - it's a 90mm square galvanised section with 12mm (?) square holes at 50mm c-c on all four sides in 3m / 6m lengths. I'm pretty sure if asked that Hilti would be able to provide manufacturing tolerance data if it's critical.

https://www.hilti.co.uk/installation-systems/heavy-duty-supports/r3131