Hole Drilling Followup

[Byron Trantham]

I posted a question asking how to drill a hole in a Bessy Clamp. Your responses are greatly appreciated. Armed with that info, I went out to McMaster Carr and found the cobalt bits. I think I need a 1/8" pilot hole bit, a 3/8" hole bit, a 5/8" Aligning Reamer and finally a 3/4" counter sink to smooth off the edges. This comes to $90.55! Does this sound right?:confused:

[Alan Turner]

That could be a bit of overkill. Just a thoght. But, if you have 350 Bessey's or so to do, it is an option.

[Byron Trantham]

Alan, I agree BUT the quantity isn't the issue. Whether I have to drill one or 350, I want a hole that will accept the clip. I have had the chance to use the newer Besseys and that clip is great. I was more interested in the process. I think the cost is so bad because of the material I am trying to drill and the size of the hole. The reamer may be replaced with a 5/8" drill bit because the roundness of the hole probably isn't that important as the clip is plastic and fairly forgiving if the hole isn't exactly round. I will have to go back to Mcmaster Carr and see if the 5/8" bit is cheaper than the reamer.

[Bruce Page]

I agree with what Alan said. The prices you quoted are for machine shop quality tools, which probably aren't required unless you are drilling dozens of holes.
If you're going to go with the pilot hole approach, I'd go with a 1/4" bit as apposed to the 1/8". The 1/4" bit will be more durable.
I thought you were drilling a 1/2" hole in the Bessey's, what's the 5/8" (Aligning?) reamer for?
How many clamps are you going to be drilling?

[Byron Trantham]

I agree with what Alan said. The prices you quoted are for machine shop quality tools, which probably aren't required unless you are drilling dozens of holes.
If you're going to go with the pilot hole approach, I'd go with a 1/4" bit as apposed to the 1/8". The 1/4" bit will be more durable.
I thought you were drilling a 1/2" hole in the Bessey's, what's the 5/8" (Aligning?) reamer for?
How many clamps are you going to be drilling?

Bruce, I think the hole is about 5/8". Actually it's probably metric. Using a steel rule it looks like about 5/8". The biggest bit I found was 1/2" AND one of the earlier posts indicated that a reamer would not only allow me to enlarge the hole but also make it round. I have to [would like to] drill 32 holes.

[Steve Clardy]

Sounds like a lot of tooling and money just for a few holes.
I would go with a 1/4" bit, then 5/8", or whatever you need for final bit, then a dremel to clean and edge the holes.

[Bruce Page]

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.

[Dan Forman]

Sounds like it might be easier and certainly cheaper to just make some "wooden shoes" for them to sit in. You could just keep them is a box and use as necessary. A 2x4 run edgewise over the dado blade on each side, then ripped to height and crosscut into however many pices are needed would yield many shoes for practically no expense. Maybe less convenient, but definately cheap.

Dan

[John Gregory]

Sounds like it might be easier and certainly cheaper to just make some "wooden shoes" for them to sit in. You could just keep them is a box and use as necessary. A 2x4 run edgewise over the dado blade on each side, then ripped to height and crosscut into however many pices are needed would yield many shoes for practically no expense. Maybe less convenient, but definately cheap.

Dan

Dan,
I think Byron wants to be able to remove the clip to reverse the clamp head and use it as a spreader rather than a clamp. I think that is his goal.

[Troy Wilkins]

I agree with Bruce. I would definitely go at least 1/4" for the pilot hole and then go to the 5/8". Just make sure to center punch your mark to keep the bit from wandering and you will be fine. For the accuracy that you need a reamer and all of the other bits would just add expense and time.

[Dev Emch]

Hmmm.... something got lost in the translation here.

Hi Bryron...

I thought you were drilling a 1/2 inch hole with no counter bore (i.e. crisp edges). Now it sounds like your drilling a 5/8 inch hole with a counter sink.

First of all, I dont know what clip your talking about. What does the usual hole for this clip look like? Does it have a counter bore on one side or on both sides?

Second, I have not had a great deal of satisfaction using counter bore drills on metal. They tend to chatter quite a bit and leave an ugly surface finish. They work great on wood.

Being that a lathe center is almost the same thing, I tend to prefer to use CENTERING DRILLS to counter sink. A centering drill is not a normal drill nor is it a counter sinking bit. They make em in all sizes but when you get to larger than 5/8 in, they tend to get big in a hurry. So a picture of this hole would be nice. MSC as well Enco have centering drills made overseas that are pretty cheap. The last 3/8 centering drill I bought was less than 6 dollars made in India.

Also if you need to counter sink both sides, a centering drill may be better as its pilot tip can self align the second counter bore or lathe center hole. So a picture helps.

ALso, for the main drilling operations, you can use any high speed drill bit along with some oil or bacon grease. Just snag some vermont americans in the borg check out line. No worries here. You DO NOT NEED cobalt or M42 or A2 or the other exotics for these holes. You not drilling a million holes nor are you drilling into hardended tool steel. Most likely, your drilling into a some form of mild steel. No Worries.

I would use a center drill to bore a pilot pit. Then follow with 1/8 inch, 3/8 in, and 5/8 in. Ream only if you want a perfect hole. But if you counter sink, then you will not notice any out of round in the hole because the conter sink hides the edge of the hole.

Oh ya, why so many bits? Forgot to add this. When drilling a semi large hole like 1/2 inch on a drill press, the bit will be under quite a bit of torque load. It is not uncommon when using a smaller type drill press to have the bits SPIN-OUT in the chuck. Now you could back off on the pressure but this is not a good idea. Metal chips carry heat away from the work item and the bit. Backing off reduces your chip load and can overheat your tooling, thus dulling it quickly. By drilling a graduation of holes, you maximize your chip load, heat removal and tool life and reduce the chances of a bit SPIN-OUT.

Best of luck...

[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

Note the drill press, the drill and the tuna fish tin with oil and the acid brush. This drill press dates back to the 1890s and is shaft driven.

See, its easy.:D

[Allen Bookout]

You might want to check and see what your local machine shops would charge. Since you have to buy the bits anyway it could be just as cheap and all of the work would be done for you. Allen

[Byron Trantham]

Allan, great idea. I just looked up a couple machine shop phone numbers. I will call tomorrow. What started out to be seemly simple has turned out to be a test of patience. I guess the problem is the size of the hole. I have confirmed it is metric - 16mm or slightly over 5/8".

[Byron Trantham]

Dan,
I think Byron wants to be able to remove the clip to reverse the clamp head and use it as a spreader rather than a clamp. I think that is his goal.

John, that's right. I've used these clips and they are a nice feature and they solve a problem I have when I use my Besseys - tipping up when the item being clamped is short. Who would have thought drilling a 16mm [slightly larger than 5/8") hole would be so problematic. I guess it's not for a machine shop but for a wood butcher "just can't get there from here.":D

[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.:p

[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. :rolleyes:

[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.