Sunday, October 26, 2014

V5.43 - Drill Press: How to pick ‘em

Alright, if you’ve followed along for the past 3 weeks, you (hopefully) know more about the workings of Drill Presses. We’ve told you about just how versatile a Drill Press can be. Now, you’ve made the decision that this is one machine your shop could really use… but what to look for? What are the most important features to consider? What will it have that will allow you to fully utilize its capabilities? Well, let’s just take a look at some of those thoughts and give you some ideas.

1: The entire Drill Press should be solidly constructed to allow for long life and the ability to continue precision work over time.

2: The Drill Press table and base should be ribbed for strength and rigidity. They should be slotted. The table should have flats or ledges on the sides, which can be used for clamping the work. (This offers convenience and safety to the user.) The table should have a precision-ground work surface which helps keep the work accurate and the base should also have a flat surface for holding large workpieces. The table should be easily adjustable, up or down – left or right, for adapting to different drilling situations.

3: The Drill Press head should be cast iron since that offers excellent support and protection for the most important parts of the Drill press, the motor, the quill and the spindle.

4: The Drill Press should be equipped with a chuck that is tightened with a key, not by hand. The chuck should have a one-half inch capacity so that it will accommodate the various size bits and accessories. Many drill Presses feature a taper-mounted chuck. By having a taper-mounted chuck, the runout of the chuck/spindle is practically eliminated and the user is assured of accurate drilling. Some chucks feature a self-ejecting chuck key which ensures that the key is not accidentally left in the chuck.

5: The Drill Press should be equipped with a depth-stop. The depth-stop will allow the user to drill many holes at the same depth as the original hole. It eliminates guessing and allows precision accuracy.

6: The Drill Press should have an adjustable motor bracket support. It should be sturdily constructed to support the motor, yet adjustable to allow for ease of setting proper belt tension.

7: The Drill Press should have a selection of speeds for drilling wood, metal, plastic, glass and ceramics. Some Drill Presses feature a triple-pulley arrangement for easy selection of 12 different speeds, ranging from a low of 250rpm to a high of 3000rpm.

We’ll stop here, for this week…

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you. 

Sunday, October 19, 2014

V5.42 - Drill Press: Speeds and Capacities

My, my. We’re just moving right along with our information about Drill Presses.

At some point we’re going to get into ‘what to look for when buying a DP’. I’m sure that will help anyone who is contemplating adding a new machine to their shop.

For now, let’s get back to our rundown.

Where’d we leave off? Oh yes, we were at the chuck and the next nearest thing to talk about is the spindle. The ‘spindle’ is usually driven by a stepped-cone pulley or pulleys that are connected by a v-belt to a similar pulley on a motor. The ‘motor’ is bolted to a plate that is located at the rear of the head casting at the rear of the column. The average range of speeds of the typical DP is 250rpm to about 3000rpm. Delta used to manufacturer a ‘super hi-speed’ Drill Press. It was so named because the bit speed was around 10,000rpm. The motor only turned at 3450rpm, but because of the belt ratio, it could really turn ‘n burn. It seems that jewelers loved it. Since the motor shaft stands vertically, a sealed ball bearing motor is best suited for a Drill Press. For average work, a one-quarter or three-quarter horsepower motor usually meets most requirements.

The capacity, or ‘size’ of a Drill Press is determined by the distance from the center of the drill bit to the front of the column - then doubled. For instance, a 12-inch Drill Press can drill to the center of a 12-inch diameter circle, but the distance from the center of the bit to the front of the column is only 6 inches. This is how all Drill Presses are measured. One of the most versatile Drill Presses was the “Ram Radial” Drill Press. This was an industrial Drill Press that was used a lot, during the Second World War, in airplane factories. The head had a long appendage fastened to its back and that casting rolled inside a ball bearing track. What this allowed was that the head could be moved backwards and forwards almost 3 feet. I’m working off memory but as I recall this press could drill to the center of a 72-inch circle, or down to about an 8-inch circle…and any and all points in between. It was such a popular concept, but one that most home shop guys could not afford, that back in the 1970’s, Rockwell International created a home shop version that could drill to the center of a 32-inch circle. It could also slide in and out, just like its bigger brother, which enabled it to be just as versatile. 

Next week we’ll outline a few tips to keep in mind when you’re out shopping for your new Drill Press.     

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you

Saturday, October 11, 2014

V5.41 - Drilling, etc…

Ok, where were we? Lost in Space? In the Twilight Zone? Maybe in a Galaxy Far, Far Away? Nah, we were just playing around in the shop talking about Drill Presses.

Back we go… A conventional DP consists of the following main parts: the base, the column, the table and the head. The ‘base’ supports the machine. Usually it has pre-drilled holes that are for fastening the DP to the floor, a work table or a bench. Some bases have a machined surface that is used to hold a workpiece that might be too large to fit on the regular DP table. The ‘column’, usually made of steel, holds the table and the head and is fastened to the base. Actually the length of this hollow column determines whether the DP is a bench model (it mounts on a work bench) or a floor model (it stands on the floor). Floor DP’s range in height from 66 to 75 inches tall and bench-mounted models range in height from 23 to 48 inches tall. The ‘table’ is clamped to the column approximately midway between the head and the base. It can usually be moved up and down the column, so as to fit odd-sized objects inside the drilling range. The table may have slots and/or clamping ledges in it to aid in clamping and holding fixtures or workpieces. Most tables have a centered locator hole through them and some tables can be tilted, left or right, while some tables have a fixed position only. Some tables have a ready-made “dummy table” which can be easily attached to the table for certain sanding operations.

The term ‘head’ is used to designate the entire working mechanism that is attached to top of the column. The most important part of the head is the spindle. The spindle revolves in a vertical position and has bearings at both ends and is housed inside a moveable sleeve, called the quill. The quill, and therefore the spindle it houses, is moved downward by means of simple rack-and-pinion gearing, worked by the feed lever. When the feed handle is released, the quill is returned to its normal up position by means of a spring. Adjustments are provided for locking the quill and for presetting the depth to which the quill can travel. The quill usually has a stroke (travel length) of 2 to 3 and one-quarter inches on most home shop models. Industrial, or heavy-duty, DP’s usually have a stroke of 6 inches.

An average DP comes equipped with a one-half inch capacity geared chuck with key. This chuck offers the best grip for the most work.

We’ll wrap up this week here and be back with you next week.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you. 

Tuesday, October 7, 2014

V5.40 - My friend, The Drill Press

So… last year I got to thinking (yes, my wife was shocked at that, too), I write about tools and I’m sure that some readers see what I write and think, “What the dickens is he talking about?”… because they have never heard of a wood shaper or a drill press or a bandsaw. So, I thought that I would introduce you to the tools.

Our next few weeks will be about what’s likely, my favorite shop tool, the Drill Press. I’ve done a few columns about the chuck and stuff, but not any about DP’s in general. I call this my favorite tool because it’s the only one that’s ever tried to seriously maim me…and it was MY fault. The story is that I was getting ready to race my dirt track stock car for the very first time and I needed to make an accelerator bracket. So I had this piece of flat steel that I had bent on one end and I needed to drill a hole in that end. I was “in a hurry” and set the bent end flat on the Drill Press table, which left the other end sticking up at an angle…and I thought  ‘oh, I can just hold it and it will be fine’… yea, right. I held it, started drilling the hole and BAM! before I could move, the bit grabbed the metal and swung it around so fast…and I looked down at my arm and all of a sudden I had this huge slice in it…started bleeding like a stuck pig and all because I was in too big of a hurry to clamp my work or put it in a vise. To this very day, I have a scar on my left wrist that looks like I tried to commit suicide. Seriously.

Anyway, back to our lesson…the Drill Press (hereafter referred to as a DP) was originally designed for the metalworking trades; however, with the availability of woodworking techniques and of cutting tools, jigs and attachments, the DP is now one of the most versatile tools in the shop. It not only drills in metal, it bores in wood and performs other woodworking operations such as mortising and sanding. In fact, after the table saw, the DP can easily become the second most important piece of equipment in the average home shop. Notice one technical distinction: it “DRILLS” in metal and “BORES” in wood. Since I am a tech-guy, such nuances are important. They really are. We’ll talk more about DP’s next time.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you. 

Wednesday, October 1, 2014

V5,39 - Table Saws: Pick a Fence

I know we kind of got sidetracked (remember, I call them detours) because of our discussion about Sawstop and Flesh-Sensing Brake Technology, but this week, we’re going back to our previous world of Table Saw fences. The table Saw fence is basically just a guide for the stock as you move it thru the blade and cut it. There are really only a couple of time-tested designs of fences. One is called the Jet-Lock fence. This name is not intended to be connected to any brand, but it was what old Delta called their basic fence system, starting back in the 1940’s. Many other saw makers have used the same basic design and they call it other things. I won’t go into the ‘name-calling’ here, but the way to tell what it is, is this: This type of fence does require a rear fence rail because it clamps on both the front AND rear rail. There are usually several adjustments that allow the operator to make it perform correctly. The usual problem with this type fence is that, when the operator pushes down on the front clamp handle (this handle is supposed to clamp the fence tightly against the front rail AND align the fence parallel to the sawblade) the fence clamps fine, but it does not align parallel to the sawblade. This is a most frustrating situation. Well, here’s the ‘trick’ solution: The front of the fence should clamp to the front rail BEFORE the back clamp locks the fence to the rear rail. The way this fence was designed, the very act of clamping to the front rail MAKES the fence align to the sawblade. As you can probably guess, if the back end clamps up first, then the front cannot make it align properly. At its most basic, if one adjusts the fence clamping sequence properly, and has taken the time to adjust the alignment of the fence so that it aligns when the front clamp engages, then this fence locks in and will be one of the best guides for your work.

The other fence style is the T-square fence. One of the most famous of those fences systems is the Biesemeyer brand. There are many other manufacturers that make a t-square style fence, but I think that Biesemeyer is sort of like the grandfather of them all… or maybe he was just the best for a many years. Either way, it is an excellent fence system. The working difference between the T-square fence and the jet-lock style is that the T-square has a much wider front clamp AND does not use a rear rail. It is usually much more heavy-duty and is so stable that it does not need to clamp at the rear. The T-Square fence is much easier to square up to the blade and because it does not have that rear rail, there is no premature clamping on the rear to interfere with fence alignment as it locks down.

Till next time….

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you