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Drill Press Modifications
by Christopher James DeLucchi

These modifications were made to a Jet 20" drill press adding for a quill lock, a good depth stop, and a mobile base.

Quill Lock Modifications:

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The Jet, and most drill presses made in Taiwan, have a split quill housing. In the case of the Jet, you remove the switch and plastic housing to reveal the split housing and three bolts, about 10mm as I recall. Two bolts enter from the right side and are used to control the normal fit tolerance on the quill. The other enters from the left through a tapped hole and is tight against the right side of the split to prevent over tightening.

1. Replace the two cap screws that enter the right side with ones that are 12mm [1/2"] plus longer. Tighten for proper quill tension and lock with nuts on the left side

2. Remove the cap screw on the left (middle) side

3. Drill through the left and right side of the split with a 5/16" (3/8-UNC Tap Drill size)

4. Place a thin piece of steel in the split to prevent the clearance drill from entering the left/tapped side.

5. Drill/chase the left/middle hole with a 25/64" drill for clearance

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6. Install a 3/8"-UNC lever handle, I used a 3/8-16 x 2.36" Ball Zinc Handle from Reid Supply Part Number: khb-100. Cost: US$8.78 in 1998. Check the length for your drill press.

7. You may need to make a threaded spacer to extend the lever handle far enough to clear the switch housing. I think I had to add about 20mm [3/4"]. I also had to enlarge the cutout that was in the plastic switch housing.

That's it for the quill lock, works perfect with a quarter turn. It appears that the reason most manufacturers have stopped installing quill locks is because they are afraid of the liability resulting from someone trying to use a drill press as a vertical mill or router -- not a good idea when the chuck is held in by a Morse Taper.

Depth Stop Modification:

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a larger image

The best depth stop I have seen is on the Delta 17-925 variable speed drill press. It consists of a knurled round-stock stop with a spring-loaded button that disengages the threaded guide rod when pushed (and slide up and down freely). The spring tension prevents it from turning from vibration, but it will turn with a little pressure. The threaded rod is smaller in diameter than the rod on the Jet drill presses. I have been able to retrofit them to several medium-duty drill presses with replacement parts from Delta.

You can also purchase the spring-loaded nut in a variety of sizes from Reid Tool Supply.


Part #

Unit Price, 1998

Drill Press Stop Rod



Drill Press Stop Scale



Drill Press Stop Nut Assembly



Installation requires modifying the quill mounting bracket and the guide bracket on the housing. I have since noticed that Reid supply carries spring nuts that look just like the one from Delta and are available in different sizes, including Metric. You may be able to get one that fits the threaded shaft on the Jet, but will still have to relocate the shaft so it is farther from the housing

Mobile Base Modification:

I find most medium-duty drill presses are too low to work comfortably -- and I am a short guy. I welded an auxiliary base from 150mm [6"] steel channel and filled it with a bag of ready mix concrete. The wheels bolted to the beam on the back that acted like an outrigger, about 800mm [32"] wide. This adds a lot of stability when moving this inherently top-heavy beast around the shop. I use a lever pole with wheels, similar to the Vega mobility kits.

Drill Press Table:

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a larger image

An auxiliary table is common in woodworking to facilitate large pieces and improve fixturing. Fences, T-slots, replaceable inserts under the bit are common design features. Some also support setting angles, perpendicular tables to simplify end-drilling long parts, dust collection, and equally spaced hole pattern drilling.

Plans have been published in most of the woodworking magazines and are sold by some suppliers. Plans from Wood Magazine are available for a small fee.

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© 2003 by Ellis Walentine by special arrangement with Wayne Miller of Badger Pond. All rights reserved.
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