Drilling cast pipe.
- Thread starter joe-90
- Start date
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Sorry this is a shaggy dog story but i feel the detail is important. I was converting a customers shop into a hairdressing salon and had the pleasure of drilling a hole in a vertical 4" cast iron pipe. The pipe was probably 90years old and required a cast boss for the basin outlets.
The adjacent pipe suffered a 500mm vertical split also, so I reasoned that the pipe was fragile and my visual inspection of the installation revealed years of neglect. I had one shot at getting this right because if the pipe failed, i would have to replace the horizontal and vertical runs of some 20 metres at considerable expense.
I purchased two hole saws with a course tooth pitch to the nearest diameter and a course half moon hand file. I marked the hole and stitched drilled the circumference with a 4mm drill bit. hole sawing took a good 40 minutes of constant pressure at a variety of speeds but no speed made any more impact on the other. Keep the cutting tool cool to preserve the hole saw, cast iron cuts dry and does not require a cutting lubricant.
Cut the hole oversize as filing it out by hand and a drill grinding wheel takes a long time to match the hole. The boss spigot is a cast finish and diameter and it may be easier to fettle the spigot in the final stages of obtaining a fit.
You will need a quality silicone sealant applied to all mating surfaces and done at the last stage of installing the boss and associated pipework as movement will undo the seal.
Good luck and be patient as I found it took 2 hours in all.
The adjacent pipe suffered a 500mm vertical split also, so I reasoned that the pipe was fragile and my visual inspection of the installation revealed years of neglect. I had one shot at getting this right because if the pipe failed, i would have to replace the horizontal and vertical runs of some 20 metres at considerable expense.
I purchased two hole saws with a course tooth pitch to the nearest diameter and a course half moon hand file. I marked the hole and stitched drilled the circumference with a 4mm drill bit. hole sawing took a good 40 minutes of constant pressure at a variety of speeds but no speed made any more impact on the other. Keep the cutting tool cool to preserve the hole saw, cast iron cuts dry and does not require a cutting lubricant.
Cut the hole oversize as filing it out by hand and a drill grinding wheel takes a long time to match the hole. The boss spigot is a cast finish and diameter and it may be easier to fettle the spigot in the final stages of obtaining a fit.
You will need a quality silicone sealant applied to all mating surfaces and done at the last stage of installing the boss and associated pipework as movement will undo the seal.
Good luck and be patient as I found it took 2 hours in all.
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I wish you hadn't told me that.
How about if I use a 4.5 inch grinder and cut four slots in a square. Hopefully the strap would cover any corners. If I made the square hole smaller than the boss pipe entry I could maybe use a jig saw with a carborundum blade to round it out? There's probably a bit of lubricant on the inside of the pipe
How about if I use a 4.5 inch grinder and cut four slots in a square. Hopefully the strap would cover any corners. If I made the square hole smaller than the boss pipe entry I could maybe use a jig saw with a carborundum blade to round it out? There's probably a bit of lubricant on the inside of the pipe
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dream on
it will however keep the dust down
not sure about the silicone .........tho` I like the stuff ...C.I. is sometimes covered with tarry paint ..........the one I did , I made a hemp grommet and the job was 2 storeys up a ladder at the weekend for ££.............I was young and keen then
and the job was 2 storeys up a ladder at the weekend for ££.............I was young and keen then
N
namsag
Brand new hole saw can`t remember what size maybe thirty five mm but it fitted plumb centre boss perfectly took about twenty five mins but felt like a lot longer. Bit of coincidence joe they are playing your music on top gear as i type this
I was once chatting to a plumber about a simular problem and he said use your angle grinder to cut the base of the pipe, put a slate into the gap ,to stop any bits falling into the drains, and then take a lump hammer to it , and then replace with plastic.
the advice did seem a bit drastic. but then he did have a lot of experience.
Good luck
the advice did seem a bit drastic. but then he did have a lot of experience.
Good luck
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