Hole Drilling Followup

[Byron Trantham]

Bryon, I think you run the chance of smoking the 5/8” reamer after only a few holes. Reaming out 1/8” of material is just too much. Typically, I don’t like to ream out more than 1/32”. I think, (IMHO) you would be better off pre-drilling with a 3/8” bit and then using a reduced shank, 5/8” bit. If your drill press setup is rigid, e.g., vice, etc. are clamped to the DP table, the 5/8” bit will drill a true diameter hole. You can find the bit at McMaster-Carr, MSC or from any of the large catalog houses for about 20 bucks. I probably have one that I could lend you.

Bruce, thanks so much for the offer. You are right about drilling too much at once. Since I started this thread I found out that the hole is in fact metric - 16mm or slightly over 5/8". I had not idea this would be such a big deal - for a non-machine shop guy. Allan suggested I ask a local machine shop and see what they would charge. Hey I am looking at about $90 for tools; they may be cheaper and certainly better that this than I would be.

[Bruce Page]

Byron, I’m afraid that the machine shop will be a bit higher than $90. They’ll probably come in closer to $200 - $250 depending on the shop rate. If you plan on heading out west, bring your 32 Bessey’s and I’ll punch in the hole for you. It should only take a couple of hours and a couple of beers.

[Dev Emch]

O.K. Lets get busy here and resolve this once and for all....

I went to my trusty MSC catalog and sniffed around a bit.

Sounds like the hole needs to be 16 mm give or take in diameter. You also have a drill press with a 1/2 inch capacity chuck.

I found an import HSS version of a 16.5 mm Silver & Demming drill bit. It has a 1/2 inch shank and bores a 16.5 mm hole. (0.6496 in). Will this work? The next size down is 14.5 mm (0.5709 in).

MSC #01344480 16.5 mm Silver & Demming Bit (1/2 shank) $8.10

Now, you desire to lightly conter bore this hole. So lets use one that fits your drill press. A four flute, chaterless, HSS counter bore. Page 159 of 2003/2004 MSC catalog. You wil want a 3/4 in counter bore but you dont need to use all of the counter bore available. Just a dab will do you above and beyond 5/8 inch.

Cost is $22.83

I would list a part number, but I dont know which counter bore angle you wish. I can get 60 deg, 82 deg, 90 deg, 100 deg or 120 deg.

If you go with a 60 degree, the part number is MSC 60281482

Lastly, this is optional but highly recommended. You need to start the hole. This bit will do this with very little bit wondering. Normal drills wonder on steel.

#4 1/2 HSS 60 degree combined drill & counter sink bit (Center Drill)

MSC 02194843 Price $5.66

With these and a bit of oil, you should be done with this in a couple of hours or less. It really is that easy!

[Bruce Page]

Dev, just for clarity’s sake, and for the non-machinist types here at SMC, a counter “bore” is used to recess a hole to accept a bolt head such as a socket head cap screw. A counter “sink” is used to champher a hole’s edge to accept a flat head screw, or to break the hole’s sharp edge like Byron is looking to do. The attached pic shows the counter bore on the left.

[Tyler Howell]

[quote=Dev Emch]Here is another URL showing my buddy Craig drilling some holes for a boring tool he is making.

http://www.antique-engine.com/shopwork/shopwork41.htm

Dev. Had a ball hanging out in Craig's shop. Real inspiring
Thanks for sharing

[Chris Gosell]

Byron,
Just A Thought, Go To The Hardware Store And Buy A Couple Of Masonary Drills. They Have The Carbide Tips. The Sizes Are Usualy About 1/32 Over Stated Size. They Will Cut Thru Fully Hardened Tool Steel And Cost Is Really Cheep. Just Be Careful On The Exit As The Carbide Is Brittle And Will Want To Crack. Feather It Thru. We Use Thes Bits To Add Holes Into A-2 And D-2 Tool Steel All The Time. A Larger Bit Could Be Used To Cs The Holes To Remove Any Burr.