Drilling one inch holes

[Pooh_Bear]

I drilled my first hole today. (first for this project).
I got a 21x23 plate 3/8 thick. Drilled a 3/4 hole right in the center.
First I drilled a 1/4 hole, then a 1/2 hole, then a 3/4 hole.
I used plenty of cutting oil and went real slow.
I had no problems whatsoever with the bits. They cut real well.
But the bit would grab just a little and the belt on the press would slip.
I tried tightening the belts as tight as I could get them.
I even bent the tightening lever. But the belts still slipped.
I got several solutions to this problem in mind. One is shorter belts.
I might just have adjusted out all the slack it can adjust.
Another is to drive wedges in from both sides of the motor to help hold it tight.

One problem I have is my drill press wouldn't drill to the center of a 21 inch plate.
So I had to take the head off and make up a special stand for it to sit on.
I was gonna leave it like that but It's not steady enough to be permenant.
I'd rather have it sitting back on the drill press column.
Either that or I'm going to have to fab up something to sturdy this up.
Cause I actually like this setup. Just needs to be more sturdy.

I'm gonna try to get some pictures.
I think this little saga needs to be recorded.

Pooh Bear

 

[CurlyDave]

I got several solutions to this problem in mind. One is shorter belts.
I might just have adjusted out all the slack it can adjust.
Another is to drive wedges in from both sides of the motor to help hold it tight.

Please don't do anything like this until you have gone down to your auto parts store & tried some fan belt dressing on the belts.

A rubber belt is really made to work with some slack in it. Fan belt dressing will increase the friction of the belt on the pulley without overtightening it, which can be quite destructive.

 

[CATMAN]

I just drilled five 1 " holes into 1/2" mild steel this afternoon, using 3/16" pilot, then going directly to 1" drill bit using cutting fluid with the drill press at its slowest speed. Worked great. I agree with a previous post that 240 rpm might be a little on the fast side. I also agree that one should back off when you see more smoke. I went till maybe 5-10 seconds of smoke, then lift bit, add more fluid(to hole and bit), repeat. When all done, I examined the 1" bit drill bit and it looks just like new. This worked for me. Note: Everytime I used a hole saw on metal with a 1/2" hand-held air drill, the hole always ended up larger than advertised bit size! (WEAR EAR PROTECTION!!! Very loud). 2nd Note: I prefer air drill (hand-held) over electric (hand-held) for larger bits and hole saws because I can overpower the air drill if the bit catches suddenly. Be careful with those big electric (hand-held) drill motors.

 

[john_bud]

Pooh,

Have you looked into having the holes punched? Many places that have a hydraulic brake will have a hole punch on it too. I bought some 1/2 plate and drew the circles where I wanted them and had sixteen holes punched in 20 minutes for $8.

 

[Egon]

That little bit of belt slipage may be to your advantage. If nothing slips and the bit grabs it can get interesting even with everything clamped down.

 

[Pooh_Bear]

Yep, I would rather have belt slippage than have the bit grab
and either break the bit and sling pieces everywhere or grab
the metal plate and have it out of control.

Never considered having the holes punched.
I won't mind drilling them if I can get the belts not to slip so much.

The drill press is a 16 speed press. 240 to 3800 RPM.
The motor has a step pulley on it and a belt goes to another step pulley
then another belt goes to a 3rd step pulley on the drill press arbor.

I think at the lowest speed the second belt is a little too long to tighten correctly.
I can hold the chuck with my hands and stop it from turning.
I think a 1/2 inch shorter belt would do wonders just for that speed.

My next problem to overcome is taking that 21x23 plate with a 3/4 hole in
the center of it and cut a 20 inch circle out of the plate.
I mounted the plate on a 3/4 axle so I could spin it.
Now I just got to find a way to actually cut it.

Pooh Bear

 

[rox]

deerhunter, when you have a chance I would lik to see a pic of that OLD OLD OLD drill you have rigged to a pipe. I can't visualise it. thx
p.s. as long as you are taking the pic how about a pic of the hole saw bits

 

[Brad_Blazer]

How about leaving the plate a rectangle? More weight and more space to hang weight if needed.

In terms of hole spacing, think about the dividing plate concept. With a full circle pattern on the rotating plate, place one stationary hole so the blade is square. Place a second stationary hole so the blade is rotated 1/2 the angle between holes in your circle pattern. More stationary holes can give you more fractions.

Brad

 

[MossRoad]

I need to drill some one inch holes. Quite a few of them.
....

I have that same drill bit set from H.F. It is O.K., but you need a beefy drill press to work those big bits. The $39.00 drill press from H.F. does not work well for this. The reason? When you put any significant pressure on the lever to lower the drill, the table supporting the work piece flexes! This results in an off centered and angled hole.

I have had great success on my backhoe project using Milwaukee bi-metal hole saws. The arbor with pilot bit was $14.00 and the hole saw blades are about $9.00 a pop for the 1.5" hole(see picture of 1.5" hole through aobut 3/8th of steel here). The arbor for the 1" blade was under $10.00 and the 1" blades are about $6.00. I use them in the crummy drill press and they don't take much pressure at all. Another advantage is that when you get to the bottom of the hole, it goes through with no trouble. With a normal drill bit, there is a tendancy to grab that last bit of metal and it takes some work to get through. I find this is especially true if you are using a hand drill instead of a drill press.

 

[deerhunterf350]

deerhunter, when you have a chance I would lik to see a pic of that OLD OLD OLD drill you have rigged to a pipe. I can't visualise it. thx
p.s. as long as you are taking the pic how about a pic of the hole saw bits

Rox,

I will bet some pics of the OLD X 3 Drill motor, the next weekend that I make it out to the Property. I just got back from there, I will have a few Pics of both ( HoleSaw & Drill Motor)