wondering off

[frank horton]

always doing plate work......
mostley held down with drilled and tapped ST/ST countersink Allen screws at 10mm dia.......
Now bought a new multi blades HSS c/sink cutter from Cromwell
bit like this but 25mm dia and made for a MAG drill.....
the mag drill is made in the USA and is roughly 300 holes old......
now my problem is the coutersink tends to cut to one side......I can get it round the prob if I push one to one side of the Mag drill when cutting....but this is Xrap way to do it.....
Have u anything better....?
dont mind buying a 2 or 3 tipped indexable cutting tool but I need to get over this....

U see the plate work usually get painted black and the shiney ST/ST screws really show out so dont want em sitting in an eleiptical hole....
cheers...be careful out there.......

 

[mike 109444]

Have you tried letting the mag drill "float" as in not switching on the magnet ? Reason if the mag is off center to the hole IT will determine where the chamfer bit will go. Or maybe position mag over hole, push down bit, turn by hand the spindle BACKWARDS while chamfer bit is in hole to allow mag to move/center in hole and THEN switch on MAG. Now it should be directly over hole. I don't know how much of the above is possible as I have never used a mag but even on a pillar drill you come across same issue and that is one way of picking up on a hole.
Failing the above there are center drills that have a 90 deg angle and could center + chamfer + drill most of hole in one operation.

 

[Hitch]

They do csks with a centre guide to keep lined up with the drilled holes. Expensive but very good.

 

[Welderpaul]

I can get it round the prob if I push one to one side of the Mag drill when cutting....but this is Xrap way to do it.....

The gib strips on your mag drill may need tightening if you can push it over? A blunt cutter will also try to wander.
Decent cutter and a sturdy drill, make sure its centred before you set off.

 

[frank horton]

the gibs are on the tight side......
what i meant was I need to pucs the whole machine over to one side a little.......
lastly the cutter is brand new......
as for another replacement, the big diameter is 25mm........so will look into a c/sink with a guide, trouble is i'll need a lot of dif sizes..........
never thought about not using the magnet but that sounds like a disaster waiting to happen........

 

[8ob]

Frank you can get step drills ground that will give you a pilot, size and countersink all in one op. I had some made for the mill, saves a bunch of time swapping over tooling.

Bob

 

[sako243]

Frank you can get step drills ground that will give you a pilot, size and countersink all in one op. I had some made for the mill, saves a bunch of time swapping over tooling.

Bob

Ah so you won't be needing your Bergmaster anymore then?