63 dia hole in plate

[howardm]

Thanks for that.
All I have is a jigsaw, welder and rotabroach, oh and a dead hammer drill.
I will have to re-think the lower pivots, they only take downward load and not a lot at that.
Howard

 

[Rick]

Change of design needed methinks.
A three of of twelve holes , and, drill brushes expire.

I don't know about everybody else but I cut slowly with holesaws. I use battery drills for just about everything as they have a decent gearbox with a lower speed, Where I can I use the pillar drill though.

I'm looking at getting some rotabroaches though as we do a lot of holes in 3mm stainless.

Anybody used these?

 

[howardm]

Hi,
I don't think rotabroach is suitable for thin materials.
Somebody else with more experience may be able to say with authority,
but my instincts would say the drill would grab the back edge and jam on the reaching the "back side".
Howard

 

[chip-kobb]

Longer life for holesaw's

I'm just looking at the close up picture of your finished hole and there is a trick that can be used to extend the life of your holesaw. when you mark out for centre of hole carry scribe line the full length of angle,measure out from centre both ways and make a dot punch mark 6mm inside the overall diameter,drill these two holes at 10mm,know when you use the holesaw the drill swarf can escape from the groove as it cut's this will help prolong the life of the tool.Use plenty of suds and a low speed

 

[Drains]

Hi,
I don't think rotabroach is suitable for thin materials.
Somebody else with more experience may be able to say with authority,
but my instincts would say the drill would grab the back edge and jam on the reaching the "back side".
Howard

This is true. But if you back it with a piece of plywood, it doesn't happen

Mind, this isn't thin anyway. A rotabroach will be fine, though slightly costly at this size.

In 3mm stainless it'll also be ok with backing as above, but slow speed, lots of push on the drill, lots of suds/oil etc.

The thing with stainless is it work hardens very quickly - the steel forms a layer of hard flat platelets which the cutter just slides over, getting hot and blunting quickly. The trick is to not let any rubbing happen - you have to keep the cutter cutting, then the metal doesn't get the chance to harden.

 

[howardm]

I'm just looking at the close up picture of your finished hole and there is a trick that can be used to extend the life of your holesaw. when you mark out for centre of hole carry scribe line the full length of angle,measure out from centre both ways and make a dot punch mark 6mm inside the overall diameter,drill these two holes at 10mm,know when you use the holesaw the drill swarf can escape from the groove as it cut's this will help prolong the life of the tool.Use plenty of suds and a low speed

Thanks for that tip.
I have changed the design and ordered a 50mm rotabroach cutter.
Holesaws just don't do it for me, probably because it needs a pillar drill.

Howard

 

[howardm]

Finally got the Rotabroach to use after 2 weeks off with a chest infection.
First one broke, but I may have abused it a bit, expensive lesson learnt, use lots of coolant.!
Rotabroach drills are really wonderful things, even the little puma I have is sooooo handy.

http://i176.photobucket.com/albums/w197/aitchem/Cradle/Cradle010.jpg

http://i176.photobucket.com/albums/w197/aitchem/Cradle/Cradle009.jpg

Too cold and wet to work today.

Howard