Drilling Holes In Aluminium Tube

[Peter GoodchildParticipant @petergoodchild34034]

Due to limited space I’ve had to put my router table under my mitre saw stand, see photos. As you can see I’ve raised the stands legs up on bricks, this is not ideal but will do just for the time being to free up space. I’m intending to add hollow tube bolted to the legs to increase height, make more stable, secure. How do I go about drilling through the tube and legs, please explain method for a newbie to understand. I’m also thinking angling the end of the tube where they meet the floor, how would I get the correct angle and actual cutting the tube?

The diameter of the legs is 38mm and the aluminium tube I’m looking at getting 4 x 300mm lengths has an ID, bore size of 41.28mm. That should be a close enough fit over the legs?

Ebay UK item number 276844073589 seller also says can supply the tubing as grade 6082T6, which is suitable for drilling.

Any help advice, appreciated.

Thanks.

 

[noel shelleyParticipant @noelshelley55608]

NO this will not work ! If I understand your dimensions your leg OD is 38 mm and your tube ID is 41.28. This is far too slack. You need the 2 tubes to be a good fit. One option is to use 38OD and fit a plug may be of wood between the 2 tubes then drill through and and use a screw to secure in the lower part. You do not say what gear you have access to, I would crimp the lower to fit inside the upper – but I have the gear to do this. Good luck. Noel.

[Nigel Graham 2Participant @nigelgraham2]

The trick to cross-drilling a tube as I assume you mean, is to ensure the drill is actually across the diameter.

It’s a bit difficult to give definite suggestions without knowing what equipment you have.

The usual way to do this , is to clamp the bar or tube in a pair of Vee-blocks clamped to the drilling-machine table, and the one under the drill chuck can be centred by winding the chuck-jaws back into the body and gently nipping the block down by the chuck itself. You need of course ensure the drill will not take lumps out of the Vee-block.

Alternatively to a Vee-block, you can a piece of channel-section of appropriate size, and on some drilling machines it might be possible to use a T-slot in the machine table.

Short of those, and I am rather guessing you carry out a lot of woodwork, make something like a mitre-block (‘L‘-section) that can be clamped or bolted to the drilling-machine table, and hold the tube in that by suitable clamps. To centre the tube, put a short piece of rod in the drill-chuck, clamp the quill so the rod is just above the flat portion of this angle-block, adjust the position of the block until the gap between the rod’s surface and the vertical face equals [tube radius – rod radius]. Clamp it then test the gap again. Obviously the first hole drilled will continue into the block so set the quill-stop so you don’t drill into the machine table.

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Cutting the tube end to the appropriate angle will require you to use an adjustable square to measure the existing leg’s angle to the floor.

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I take it Noel’s suggested plug is one with two diameters to conect the two tubes end-on. Such connectors commonly have an intermediate ridge 2-3mm thick, of diameter that of the OD of the larger tube, for proper axial location.

Drill the plug in place in the tube so if the hole is not strictly diametral, the screw or pin will still pass through the two components.

Another approach is to telescope the tubes with a sleeve between the tube walls, the sleeve here 1.62mm thick wall. This can be of plastic or metal, and it may be possible to find suitable tube that if necessary could be cut lengthwise so it closes down or expands a bit.

 

[BazyleParticipant @bazyle]

To drill the tube make a bit of wood that fits into the bore so that it is supporting the tube as the drill breaks through. You only need the wood to be correct diameter but 1 in long s you can move it along for the next hole.
Mark the centre for the hole with a small centre punch or nail and enlarge that mark with a small drill – like 1mm twiddled by hand, to make a bigger dent to keep the next drill on target. Increase drill size in stages as the flat bit at the end of each drill needs to fit in the previous hole to avoid wandering.

To mark the end of the tube for cutting. Fit tube in place on leg uncut resting on floor.  Place piece of wood say 1 inch square on floor next to leg/tube. Mark tube with felt-tip along top of wood. Move wood round tube marking off as you go. This shoud give you a mark all round at an angle – don’t cut this line use it as a reference to mark the actual lne as near the end as practical.

[Adrian R2Participant @adrianr2]

Rather than faff around cutting the tube to an angle, look instead for rounded rubber feet that will fit over whatever size you select. Variously described as “chair feet”, “end caps” or similar.

[duncan webster 1Participant @duncanwebster1]

38mm is suspiciously close to 1.5″. If I’m right you could just buy longer lengths of tube and replace the whole length

[BazyleParticipant @bazyle]

Looking again at the bench the legs are bent sheet metal. Extend with steel angle iron. Far easier to work. use a substantial overlap and put in extra holes while you are about it to change the height if it doesn’t suit first round.

[duncan webster 1]

On duncan webster 1 Said:

38mm is suspiciously close to 1.5″. If I’m right you could just buy longer lengths of tube and replace the whole length

This!

The legs are simple tubes with cross holes at the top so its far easier to make new ones of any suitable material rather than faff about with what you have.

Still have to drill the holes of course. For quick and dirty I’d fabricate a hollow block with a square aperture a snug fit on the tube rather longer than the bit of tube containing the holes. Simple screw four bits of whatever you have together whilst clamped round the tube. Two L sections first as per Nigels idea then fix together whilst calmer found tube. Be neater to cut off the overlaps but for a one time job why bother. Marking out the hole positions with a squat aperture is relatively easy then its just a matter of drilling straight to get guide holes. Inspector Meticulous would put some metal tubes in to help guide the drill. OTT for a one time job I think.

Assuming the legs just bolt up into the corner of a pressing with no guides inside look seriously at using square tube and marking out direct on the job. Or simply say stuffitt and use square timber. Nowt magic about metal legs.

Clive

[Howard LewisParticipant @howardlewis46836]

Angle iron would be a better, and easier, way of increasing the height

To find the angle at which to cut the bottom end, make up a template, (cardboard, or sacrificial sheet metal or hard board) and then use this to mark the angle iron.

But then it would be advisable to have some form of flat plate under the end of each leg, to spread the load a little. (Taking all the weight on the end of the angle will put a lot of pressure on the floor, because of the weight bearing on a small surface area).

Howard

[duncan webster 1Participant @duncanwebster1]

The thing with the angular legs is ths router table, not the thing which wants raising

[JasonBModerator @jasonb]

Yes it is the folding dewalt mitre saw stand with ROUND legs that need extending. The one jacked up on bricks. There are sprung pins in the tops of the legs as well as pivots so a bit more work involved than just getting a longer tube.

EDIT. It’s a JCB one so may not have the spring pins.

Do you really need to drill right through. I’d use a cone drill and only go through one side, self tappers or TEK screws into the existing legs.

You can work out the compound angle easy enough by measuring side splay and front/back splay. Simpler to just slip a loose extension over a leg and use a block of wood and sharpie to scribe round parallel to the floor.

But as you have a compound mtr saw just set the table angle to one rake and the saw angle to the other rake and chop through your tube.

[Peter GoodchildParticipant @petergoodchild34034]

I have a floor standing pillar drill and some Vee-block clamping stuff, see attached photos. photos Will see if imperial ID tube closer to the OD of legs. 

[Peter GoodchildParticipant @petergoodchild34034]

I felt a through bolt would be more rigid?

[Nigel Graham 2Participant @nigelgraham2]

It would be! That’s how I’d do it.

Aha – looking at your two photos you have an appropriate drilling-machine, angle-plates and clamp-set.

Clamp the tube in the corner formed by an angle-plate and the drill-table, with a thick sacrificial pad under the tube and the drill’s depth-stop set so you don’t damage the table.

Scraps of old laminated-chipboard make good pads for work like this. You may anyway need fairly deep packing so the drill will go right through the tube without the chuck hitting the angle-plate. I do a sort of dummy run with the work-piece out of the way and machine off, to verify such clearances.

 

Another approach:

Unless the table rim is too high to allow this (it will be on some drilling-machines) you might be able to use one of the table Tee-slots as a sort of Vee-block, with the drill centred in the slot with healthy clearance around it, and again with the depth-stop set so you don’t drill into the slot floor. This will depend heavily on how much you can move the table and head around the column, relatively to each other.

If this set-up is feasible, I would suggest making a bridge-clamp to take the studs etc you have, because you will need clamp from the slots quite a way from the tube.

I have done this by screwing or bolting two lengths of batten together, using about four fastenings with appropriate spacers; the wood edge-on such that the load is onto the width rather than thickness, for the more rigid configuration of the wood. Effectively it produces a clamp with very long slots for plenty of fitting, using two studs etc., spanning the tube at the clamp’s mid-point. Tighten the nuts gently and evenly, keeping the battens level.

A shallow Vee-notch cut in the battens will make the set-up a bit more secure and spread the clamping-load on the tube slightly.

 

It is a wise idea to support the inside of the tube if thin-walled, with a wooden plug. This, if of such a length that the drill goes though it, slightly reduces the risk of the drill snagging as it breaks though the metal – but the inevitable burr may make it hard to remove!

[duncan webster 1Participant @duncanwebster1]

You could of course get some 1.5 ” od tube and find a local fabricator to weld it on. A few quid in the tea fund should cover it.

[duncan webster 1Participant @duncanwebster1]

Oops ignore me its aluminium, not as many competent ally fabricators out there

[JasonBModerator @jasonb]

Place 3 or 4 TEK screws around the tube equally spaced and that would be as rigid if not more than a though bolt.

[Peter GoodchildParticipant @petergoodchild34034]

Thanks for the input everybody. I’ll update and let you know how I get on.

[Author]

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