• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

Center drilling problems

V

VicHobbyGuy

Ultra Member
Beginner here, using a 7x mini lathe. I need some help with a problem center drilling.
Sometimes it's straightforward, but often I get the following problem: When I advance the center drill into the spinning workpiece, the drill 'kicks' off center by about a mm (or two) and then proceeds to cut a small circle with a 'pip' in the center. NB this is a 'mini-lathe' so nothing about the tailstock is extremely solid, but it is adjusted to be on-center. Is this a problem with the tailstock, the drill (I've tried a few), the speed of rotation of the work, or a technique issue? I usually don't advance the drill very forcefully into the workpiece; should I? This happens with both brass and steel workpieces, and not every time, so it is frustrating. I generally have to re-face the part and try again, and sometimes that does the trick. Any hints would be much appreciated.
 
Last edited:
David_R8 said:
Is there play in the tailstock
Click to expand...
There's as little as I can manage - it's only really solid when the quill lock is full on, but then I can't advance the drill. The tailsotck is solid, but the quill isn't. I thought the idea was that the drill should 'self-center' on a spinning workpiece?
 
I had this problem early on (only weeks ago!). I height-centered my facing cutter better, getting rid of every trace of a little nubbin at the center of the face and now my centers go in better and I break fewer center drills. Though I still blow them out too often.
 
PaulL said:
I had this problem early on (only weeks ago!). I height-centered my facing cutter better, getting rid of every trace of a little nubbin at the center of the face and now my centers go in better and I break fewer center drills. Though I still blow them out too often.
Click to expand...
Thanks, I need to check the center finish better with the magnifier Optivisor on, I guess. I haven't broken a center drill yet, so there's still 'room to grow' for me :)
 
On the same topic- Recommendations for good quality center drills would be appreciated. I'm not interested in paying KBC/Accusize triple the price for the same ones I got from Ali Express, Banggood but $40+ seems a lot...https://www.toolstoday.com/global/v-12361-51670.html
I usually use the center drill I got in my night school class in the 1970s - it's been waiting all these years for me to get a lathe! :) Truly 'old school quality', I guess, but even with it I have these problems.
 
Last edited:
I also had (emphasis on had) a set from Banggood. Basically one-use items.
 
DPittman said:
I ordered a set from Aliexpress and they were pure garbage. I've also had some worthless ones from Amazon. I also paid $45 for an American made set from KBC and am happy with them. There has to be some that are reasonable price but decent quality out there, but I haven't found them yet.
Click to expand...
I saw these at KBC, but since the country of origin isn't marked, I'd assumed they were not from the USA.
https://www.kbctools.ca/itemdetail/1-033-100 $52

https://www.kbctools.ca/itemdetail/1-031-200 KEO $62 KEO brand
 
I barely know what I'm talking about, but I wonder if you have checked that the spindle and tailstock are in-line? I'm wondering if the tailstock is a bit off front to back if that might not be part of the problem. Drill would be working like a cutting tool close to, but not on, centre.
 
You must log in or register to reply here.
Back
Top