Hi all,
We have just done a job where we needed a flat bottom hole at the bottom of deep bore relative to the bore diameter. The hole is 32mm dia and 159mm long. We are producing these parts on a cnc slant bed lathe using the turret.
We are using an Allied Maxcut spade drill to produce the holes and speeds and feeds are as per manufacturers guidelines. We first go in with a standard drill point to maybe 1mm past finished depth, and then go back in with the flat bottomed insert to remove the drill angle at the bottom of the hole. The problem we get is, the standard drill point gives us a lovely finish that we are very happy with, however, when we go back in with the flat bottom insert, we get vibration/judder marks where the insert engages with the material when it starts removing the original drill angle. This doesn't happen on every part, but is inconsistent enough to annoy the hell out of me.
As a rule these marks are not overly detrimental to the operation of the part, but I am always looking for ways of improving our processes and whilst the finish isn't critical, it's bad enough that I want to do something about it.
So my question is, does anybody have any tooling recommendations for drilling flat bottomed holes in small diameters when in relation to depth of bore, such as the 32mm dia X 159mm deep bore discussed here. The bottom face doesn't have to be perfectly flat, so the likes of a U-drill insert finish on the bottom would be acceptable. We do various parts with similar bore sizes but to various depths, so I am looking for a versatile tool such as the Allied Maxcut spade drills we have, where we only need to order up different insert sizes. We recently did a job with a 32mm bore, but it was 500mm deep with a flat bottom, so whilst I may be able to get a U-drill to get to 159mm deep (just) that tool wouldn't do the 500mm deep bore.
Any thoughts on other tooling would be a great help.
Cheers
Sent from my iPad using Tapatalk
We have just done a job where we needed a flat bottom hole at the bottom of deep bore relative to the bore diameter. The hole is 32mm dia and 159mm long. We are producing these parts on a cnc slant bed lathe using the turret.
We are using an Allied Maxcut spade drill to produce the holes and speeds and feeds are as per manufacturers guidelines. We first go in with a standard drill point to maybe 1mm past finished depth, and then go back in with the flat bottomed insert to remove the drill angle at the bottom of the hole. The problem we get is, the standard drill point gives us a lovely finish that we are very happy with, however, when we go back in with the flat bottom insert, we get vibration/judder marks where the insert engages with the material when it starts removing the original drill angle. This doesn't happen on every part, but is inconsistent enough to annoy the hell out of me.
As a rule these marks are not overly detrimental to the operation of the part, but I am always looking for ways of improving our processes and whilst the finish isn't critical, it's bad enough that I want to do something about it.
So my question is, does anybody have any tooling recommendations for drilling flat bottomed holes in small diameters when in relation to depth of bore, such as the 32mm dia X 159mm deep bore discussed here. The bottom face doesn't have to be perfectly flat, so the likes of a U-drill insert finish on the bottom would be acceptable. We do various parts with similar bore sizes but to various depths, so I am looking for a versatile tool such as the Allied Maxcut spade drills we have, where we only need to order up different insert sizes. We recently did a job with a 32mm bore, but it was 500mm deep with a flat bottom, so whilst I may be able to get a U-drill to get to 159mm deep (just) that tool wouldn't do the 500mm deep bore.
Any thoughts on other tooling would be a great help.
Cheers
Sent from my iPad using Tapatalk
