[Fudd]

I have a job for some 1.00" +.003 -.000 holes 2.635" deep in Mild steel. The holes need to have a close to flat bottom. Have you guys used any indexable drills that will hold this tolerance? I have a smaller size .937" that I plan to circular inperpolate to get the size hole I need, but would like to use a 1.00" drill if possible.

Thanks,

Scott

[solgood]

Scott

first thing is index drills wont give you a flat bottom so you will have to use your .937 and finish with an endmill.

second is yes a good index drill will hold +.003-.000

[Fudd]

The bottom does not have to be perfectly flat. Most of the 2 insert drills that I have seen will product flat enough bottom. What drills would you recommend?

Thanks,

Scott

[nervis1]

I doubt you will drill and hold .003 -.000. You will need to drill undesize and ream. Drills are crude hole makers. That being said I have an indexable 1" Mitsubishi drill that is like buttah'.

[solgood]

OK NERVIS1 i do it all day long, never under sized but never over .003 over sized. maybe its the machine(s) you have.

[nervis1]

Maybe so, I'm used to using a 95 Fadal so maybe that is my problem.

[Fudd]

Solgood,
What drill are you using? I have a Sandvik corodrill 880 in .937" That I am planning on using to plunge 1st then interpolate to get to 1.001". By the way I am using a 1990 Fadal 4020.

Thanks,

Scott

[cdlenterprises]

I've always had good luck with Carboloy drills either the SD52 or SD55 series. I wouldn't recommend drilling the holes to size but you may find a metric size that will get you closer to the 1.001 before interpolating it.

:cheers:

[kuss22]

Solgood,
What drill are you using? I have a Sandvik corodrill 880 in .937" That I am planning on using to plunge 1st then interpolate to get to 1.001". By the way I am using a 1990 Fadal 4020.

Thanks,

Scott

I have 10 Sandvik Coromant Corodrill 880's with 40 inserts for sale. (All new in original packaging) Make an offer if you’re interested! See Item number: 280160832506 on ebay if you want to place a bid. You can also copy and paste the following link:

http://cgi.ebay.com/10-Sandvik-CoroD...QQcmdZViewItem

Let me know if there is a certain area to post this information. I feel that all the people on this forum will be the most interested in these!

[Fudd]

E-mail sent

Thanks,

scott

[kuss22]

Please feel free to ask questions for I will try my best to get you the answers quickly as possible!

[Metalcutter]

Try a K-tool flat bottom drill. Their website is http://www.ktoolinc.com . I use these all the time. They have a nice flat bottom (except for a tiny tit in the middle). They tend to cut a bit undersize so shimming out the outside insert might be in order. They work better cutting a blind hole.

[highspeedmazak]

Ok I have held +.002 -0.0 with two different types of insert drills first valinite second wakashaw(bad spelling) both were pecked in mild steel 3" deep peck was .200, rpm 3000 and the feed was .0028 per tooth I ran this in a mazak25/405(large mazak) I did not have through the tool coolant so that is why I pecked it. It ran for years like this with no problems. I had my inserts cryo treated. On the mazak it was (350 at .0028) Now take in mind that I had a large mazak. What machine are you planning on running this on?