- Examine an older 10" Craftman drill press for problems
- Add a keyless chuck
- Build a drill press table
Drill Press Secrets
A good drill press with a table will make building the CNC router easier. This means drilling holes at ninety degrees to the surface, the right size and in the right place, but with a lot less frustration. What follows is a discussion of the features of a good drill press that can be used to improving yours or buy one.
First, take a look at the excellent article by Grant Erwin, http://www.tinyisland.com/htbdrillp.txt, on how to buy a drill press and can also be used to examine your drill press to see how it stacks up. I have a Craftman 10" drill press that I bought several years ago which I need to examine, closely. Before we start that, here are two other articles worth looking at: http://www.victornet.com/reference/Drill_Chuck_Mounting.html and http://www.jacobschuck.com/drill-chuck-install.asp.
What is Runout?
Runout is the wobble at the drill bit. Most bench top drill presses come with cheap chucks which are probably the biggest source of runout. To measure runout you will need a dial indicator and some way to hold the indicator. First, chuck up a dowel pin and place the indicator against the shaft. A Forstner or a starter bit will also work. Rotate the chuck by hand and read the extremes of the indicator measurement. If this indicates there is .003" or more runout, then place the indicator against the chuck itself. If the runout there is less that .002" then the jaws of the chuck are bad. If the runout at the chuck is bad then remove the chuck and check the spindle taper in the same way. If that checks good, buy a new chuck. A good quality drill press will have less than .002" runout at the bit. If the runout at the taper is greater than .002", you will need a new drill press.
I have an old 10" swing, Craftman drill press and there is visible runout. I will measure the bit, chuck and taper runout of this press and post the pictures here. The measured runout at the Forstner bit shaft is .013", at the chuck it is .002" and at the taper less than .001". Apparently, the jaws themselves are damage or worn.
|Drill press with chuck removed. Drifts sitting on chuck.|
|Indicator against forstner bit.|
|Indicator against chuck body.|
|Indicator against taper JT33 taper.|
The chuck is held onto a JT33 taper with a screw up inside the jaw which I removed Attempts to dislodge the jaw have failed. A chuck removal drift set has been ordered from Wholesale Tools and will arrive Friday along with a keyless chuck and a wiggler. The drift consists of two U shaped pieces of tapered steel. If you have a large bench or a floor drill press, the jaw is probably mounted on an arbor made up of a JT33 and a Morse MT2 tapers. To remove the arbor you will need a MT2 drift.
Before the new chuck was installed, the taper both on the drill press and the chuck were cleaned with low odor mineral spirits. The new keyless chuck was placed, lightly, onto the JT33 taper and pushed up hard. Making sure that the chuck jaws are inside the chuck, I placed a piece of wood against the bottom of the chuck and struck upwards with a hammer, a couple of good raps. This chuck does not use a screw, as the old chuck did, so if the chuck isn't well seated it will fall off. The picture shows the chuck in place. Measured runout is now .001".
|Keyless chick in place.|
Sources: Harbor Freight, Wholesale Tools, Victor Machine Exchange
Making a Drill Press Table:
Though you could build the CNC Router without a drill press table, it will make aligning and drilling the holes in the project parts easier. Besides it is a useful rig to have in a woodworking shop.
A bench top drill press with a 10 inch swing, where the swing is twice the distance from the post to the drill bit, should be acceptable. Most of the readily available bench drill presses have problems which you will find by reading the reviews. The important points of precision are runout and perpendicularity where runout is the wobble at the chuck. This wobble will result in an oversize hole being drilled which would allow the precision rod of the CNC router to wobble. Perpendicularity can be adjusted using shims under the drill press table.
The drill press table is a very handy woodworking accessory and is typically 12" by 24" with an adjustable fence. See the picture below. This table was made by laminating two sheets of 1/2" and 3/4" MDF with wood glue. Two aluminum T-Tracks which are 14" apart and 11 3/4" long were purchased from Amazon. These tracks use 1/4" hex head bolts to position the fence and clamp work pieces in position. The fence shown here is 2" high and is made by laminating a 3/4" birch plywood to 1/2" MDF. Two 9/32" holes are drilled vertically through the fence 14" apart. 3" hex bolts with knobs hold the fence in place. This table is bolted to the drill press table with 1/4" carriage bolts. Two coats of Zinnser Sealcoat is used to seal the table. Sealcoat is not water based and will not raise the surface of the MDF.
|Drill press table with simple fence.|
This table was built 13" wide and is the reason the T-Track appears to be short.
List of Materials:
- MDF, Homedepot
- Poplar edging, HomeDepot or Lowes
- T-Track, Amazon from Router Table Depot, $8.25 pair
- Knobs, Incra Build-It set, Amazon, $10.99
- Additional Hardware, Lowes or HomeDepot
An additional fence is in the work which is 4" high and incorporates a Incra T-Track Plus that includes a sliding scale, $14. at Amazon. The adjustable stop is from Peachtree, $7. This will be pictured once completed.