Drill Press

© Brooke Clarke 2007

For some time I've had the Harbor Freight 44506 Five Speed Drill Press in my garage and it gets a fair amount of use doing things like:

• drilling holes in a 2x4
• enlarging holes in printed circuit boards that the maker did not fully drill
• drilling holes in jewlery
• drilling holes in sheet metal
• used as a lathe by turning on it's side and manually filing or Dremel tooling bolts into eyelet tools
• others I'm not remembering
• making a countersink deeper (bit shown in photo above)
  

It would be nice to have a lathe either a full size one like shown on my lathe web page, or one of the smaller ones.  One of the key operations for the lathe would be to drill and tap a hole along the centerline of the work piece.  For example to make a spacer like used on the 257477BA battery adapter.  Or a new battery adapter where the spacer is very important so prototypes are needed.  Or a new product that has the shape of a cylindrical battery with contacts on the end.  Then it occurred to me that my existing drill press could drill and tap the holes.  That's how this web page got started 21 Nov. 2007.

The Harbor Freight Bench Top Drill Presses are:

HF	44506	38119	44836	38142
Enco		125-1072		308-0056
Grizzley		G7942		G0485
Speeds	5	5	12	16
Swing	8"	8"	10"	13  7/8"
Quill	2"	2"	2 3/8"	3  1/8"
Morse Taper	JT33	JT33	MT2	MT2
HP	1/3	1/3	1/2	3/4
Table	6  5/16" x 6 1/2"	6  5/16" x 6 1/2"	7  7/16'' x 73/4''	11 /2'' dia
$ 2007	discontinued	70 -90	110	195 - 240

It may be that the either of the two larger drill presses could be retrofitted with an end mill holder such as item 45046 (3/8") or  38142 (1/2").  The ball bearings in a drill press are not designed for loads at right angles to the spindle axis.  That makes for two possible problems, a lot of slop (TIR) on the spindle and if heavy cuts were made destruction of the bearings.
An end mill should NOT be used in a chuck because the chuck can not grip well enough to prevent the bit or chuck with bit coming loose from the machine.

After Googling for a 10" drill press many were found, but they all seemed to have JT33 or non specified spindle tapers.  There are a number of them sold for wood working and one of those has a quill lock.

This is a bench top drill press with a chuck that can hold a 1/2" drill.  The cost is about the same or lower than a hand held 1/2" drill and you have the advantages of a drill press.  It can easily be laid over on it's side and so can be used as a simple lathe with hand held tooling.

The motor is an AC type rated at 1/3 HP.  There are 5 step pulleys on both the motor and spindle shafts allowing for 5 speeds of 620, 1100, 1720, 2340 or 3100 RPM.  The motor is rated at 1750 RPM so there may not be a 1:1 pulley combination.  Note with a pulley system the motor runs with it's full power potential and the torque is traded for speed.   One of the dangers of this or any drill press is that the drill bit may bind and grab the material.  When this happens the drill does not stop but instead has the tendency of spinning everything and if you hands are holding on they you may suffer some pain.

I have the speed set to 620 RPM and it seems to do fine on everything.





The three levers that are the handles for lowering the quill tended to unscrew and even fall on the bench.  The chuck key handle tended to become loose.  Both of these were fixed with a drop of Loctite 222MS thread locker.

The key to drilling cylindrical parts is to use a collet to hold them.  The "5C" collets are very common and considerably lower in cost than any of the others.  So a simple 5C collet holder mounted to the drill press should work.  It happens that Enco has a 5C set on sale and when you buy some more related stuff and your order goes over $ 200 the shipping is free.  So yesterday (20 Nov 2007) I placed an on line order and this morning (21 Nov) UPS delivered the first box containing  the 235-0000 5C Collet Set. . . Oh No another Enco Packing Problem.
This box contained the four items that make up the set.

	235-6080 5C Vert/Hor Collet Fixture - The handle of this punched the hold in the shipping box. The advantage of this 5C collet holder is that the height is a fraction of an inch more than the length of a 5C collet.  Since the drill press only has 2" of quill travel and not much room between the chuck and table this is important.  The Enco 2007 catalog package photo on page 400 shows  the 235-6085 5C Vert/Hor Collet Fixture but the table listing part numbers shows the 235-6080 and that's what I received. The more expensive and physically higher 235-6085 loads the collets by removing the nut with lever from the top. This 235-6080 5C Vert/Hor Collet Fixture has the collet inserted from the top but then the loose tommy bar is needed to tighten the nut that's on the bottom.  If the fixture is not bolted down you can use your finger to tighten the bottom nut. When the lever is pulled forward it cams a sleeve inside the fixture pulling the bottom end of the collet down causing it to close.  The lever may get lost since it has no home. May be made by Zhengzhou Machinery Co., Ltd. 2 Apr 2008 - this is getting more use than I expected.  It can hold round stock either axis vertical (in the photo orientation, or axis horizontal, thus allowing drilling round stock easily)
	The Enco 5C Collet set 230-4017 is supposed to have all the sizes between 1/16" and 1 1/16" for a total of 17 collets, but this set also has the 1 1/8" collet for a total of 18 pieces.  The box would hold 20 collets. The 15/16" collet is installed in the fixture in the above photo.  They are marked "5C" and the size on the end making it easy to tell which one is installed.
	5C Collet The face (bottom in photo at left) has three 1/16" slots that run back  about 2 1/4" and are what allows the collet to grip the rod.  There is a 1/8" wide slot about 0.065" deep running from the rear of the collet about 1.9". Whatever holds the collet will have a pin riding in this slot that keeps the collet from spinning. The external thread is used to trap the collet to allow the nose taper to force the jaws closed. The internal thread allows accessory item, like a stop, to be installed inside the collet. The body OD near the threads is 1 1/4" and the clear ID is around 1".  That puts a limit on the bar stock that can be fed through the collet.  But is NOT a limit on how large an item can be held on the front. The largest collet in the set above is 1  1/8".  There are 5C collets that are a few inches across.
	235-7050 5-Piece 5C Collet Block set contains a square and a hexagonal collet block, a couple of nuts and a locking handle.  The tapered end is at the top of the blocks in the photo and at the bottom front you can see the head of the locating pin which aligns with the slot on the 5C collet to keep it from turning.  You would use either the nut or the cam lever to tighten the collet. I'm not yet sure if these will work for me with the Drill Press.  Typically a part would be held in the collet which in turn would be put into a vise.  By rotating the block you could make four or 6 cuts symmetrically. I do have a small circular saw and an arbot to hold it on order.  The idea is to use the drill press to cut off the rod stock.
	239-9030 Collet Rack is about 9" x 12" and holds 30 collets. Some assembly required. One of the 5-0.8x10 mm screws has bad thread and no spares. I think Enco has sent a full box of these screws, since it was easier for them.  If you need any you can have a few for the postage & envelope cost.  Just ask.

The "T" slot  patent 359369 by Fredric W. Taylor was issued Mar 15, 1887 current class # 409/219 ; 33/567; 33/568 prior to then the table had a smooth surface and long clamps were used.  The old plain tables would get a arch after use because the clamping forces were acting over a long distance and the repeated stress of the cutting tool would  warp the table.

The 8" drill press table and base have slots designed to accept 1/2" "T" nuts or bolts.  The "T" series parts come in a number of sizes.  The 1/2" "T" nuts or bolts use a 3/8-16 threaded bolt or nut.  There is typically no information about this on the web pages that are selling the drill press or the accessories for them.  I discovered this by making drawings of the various parts.  "T" fittings are on order to install the 5C collet holder and should be here in Nov 2007.

Here is an assortment of components specifically for 1/2" T slot use.
On the left is a Flanged Nut (407-5024) with 3/8-16 thread.  The flange is 0.830" dia.
In the center is a 1/2" T bolt.(407-3010) with 3/8-16 thread and is 1.5" long.
On the right is a 1/2" T nut (407-2500), unfinished Rockwell 80 washer (891-5671) and a 3/8-16x1.5" Grade 5 cap screw (325-3738).

I got a number of each of these in the hope they will come in handy not just for the first setup, but future setups.

Drill Press to 5C Collet holder  T-Nut & Bolt	Drill Press to 5C Collet holder  Bolt & Nut

There are a couple of problems.  The T-Nuts are not tapped through, but stop a thread or two short.  I think that's done so that you will not run a bolt into the T-slot in a mill table or other T-slot that has a solid bottom.  This means that the bolt length needs to be within a few turns of the correct length, or you add an extra washer or two. 

The other problem is that the 0.7" slot in the 5C collet holder is almost as wide and the OD of the heavy duty washer or the flange on the grade 5 nut.  That makes is difficult to install since one side of the washer tends to fall into the slot.  Using washers with an O.D. of 0.978" is better but still not a clean solution.  I've seen rectangular metal plates with a center hold used in this application, but they don't seem to be a stock part at Enco.

Making the rectangular plate would be a solution.  Another would be to tap the T-block all the way through, or maybe drill a clearance hole in a couple of T-blocks.  That way a T-block could be used upside down on top of the 5C with a bolt going into the T-block under the drill press table.

When working with small drill bits, like a tap drill for 2-56 or 6-32 threads like was being done prior to taking the above photos, there's no need to bolt down the collet holder.  In this case I was working Delrin and using small tools that would snap before they could move the collet holder.  Same's true when the 4" vise (see below) is used.  But when a larger diameter tool is used that has any chance of jamming then clamping is required.  The instruction booklets for the drill presses show a 2x4 being drilled where it has been  rotated clockwise about the drill center line until it touches the column.  That way if the bit jams there's no room for the 2x4 to move.

Used these to deepen the countersink in a battery adapter where the first design used 0.060" thick aluminum but the latest version used 0.050" thick aluminum and now the 4-40 flat head screw bottomed on the PEM insert rather than seating on the aluminum.  So the PEM inserts were modified by using the countersink.

Flat head screws (fasteners) are available with different angles.  The 82 degree type is what you get if the angle is not specified in the U.S. but in the U.K. it's 90 degrees.  There is also a 120 deg version.   Enco has a catalog page Introduction to Spotting Drills & Countersinks.

The meaning of the numbers is a standard.

No.	Body dia	Drill dia	Drill Len
1	1/8	3/64	1/16
2	3/16	5/64	5/64
3	1/4	7/64	5/32
4	5/16	1/8	1/8
5	7/16	3/16	3/16

This is Harbor Freight set 42279, HSS made in India.
A more common use is to start start the hole for another drill.  These are very stiff unlike drill bits that tend to wander.  Another use is making the countersink for a lathe center.  The drill part extends the point so the center will be seating on the cone and not the point.  For a dead center the added volume of the drill will make a place for oil.  But for use on a lathe a different angle is needed to match the dead or live center.

These are very handy for many drilling operations because they are much much stiffer than ordinary drills and so go where they are aimed.

Economy Model Indexing Spin Jig

Enco 235-6011. Manfacturers model PF70-5C.
My hope is that a part held in the collet can be machined by hand rotating it while a tool that's powered (drill press, moto tool, Mini Cutoff Saw) does the cutting.

Index plate numbered in 10 degree steps and lined at 5 degrees. Vernier holes for 0 to 9 allows 1 degree steps. Aluminum knob locks spindle. Black sleeve traps spindle left to right.	Crank is connected to hollow tube that threads onto collet. With aluminum knob tight crank open or closed collet. With aluminum knob loose and indexing pin out crank turns part in collet.

The Enco description says that the spindle travels 2 1/16" for flute grinding.  But as soon as the index wheel moves away from the body and index pin the collet is no longer indexed and is free to turn, so it's not clear what keeps the spindle from turning.
A 3 mm hex key is needed to loosen the sleeve to allow the side to side motion.

The base does not have slots or holes for hold down so needs to be clamped.  I drilled a couple of holes that were extended into notches.  The material is very easy to work and seems more like carbon than iron.

The Spin Index did a nice job de-liding a failed TO-5 packaged transistor.  See photos on the HP 4328 web page.

The hole in the aluminum knob may be a place to put the index pin when it's not in a vernier hole.
Small rotary tools to go with spin indexer.

	Stone
	ball end mill

The height of the center of the spin index is DIFFERENT than the height of the 5C collett holder.  This is too bad since it would be nice to put a tool (drill bit for example) into one of them and use as a hand powered lathe.  Need to look for another collet holder that matches the spin index.

Things that did Not Work

Saw

It may be possible to use a slotting saw to cutoff small rod stock that's being held in a 5C collet.
This is a 3" x 5/64 cutting edge blade with 30 teeth.  The central hole is 1".  The arbor is the stepped type with diameters of:  0.995, 0.868, 0.745, 0.618, 0.495.  The cap is held on with a flat head screw that uses a 3/16" hex wrench.

The arbor shank is 1/2" O.D.

The saw blades come in a number of thickness and diameters.  The idea is to end up with a rod whose end is square to it's centerline and smooth, not the end you get when using a hack saw.

There are a couple of problems.  One is the arbor is designed to be mounted in an end mill holder (you can see the flat on the shank in the photo at the left).  Although the arbor could be held in the drill press chuck, it may work itself loose.  If that happened and you had a free spinning saw blade bouncing around like a top there might be a sefety issue.  The other is the pitch of the saw.  This is a 3" diameter blade with only 30 teeth so the pitch is PI/10 or 0.314".  It's good if the pitch is smaller than what you want to saw so that the saw always has a tooth cutting material.  What you don't want is to have the saw cutting air then the material then air, etc.

27 Nov 2007 - Harbor Freight is advertizing a Mini Cut-off Saw (42307) for $20 that has a 2" blade with 100 teeth (1/16" pitch) turning at 7,800 RPM that looks like just what I'm looking for. The Mini Cut-off Saw arrived 8 Dec 2007.  It weighs 3 pounds and has a 3/4" capacity.

Harbor Freight 438 4" Cross Slide Vise

Since these also come in 5" and 6" sizes I thought the small one would fit the 8" drill press.
It does NOT fit.  There's no way you can position the 4" cross slide vise on an 8" drill press and be able to install two mounting bolts.

The Enco  cross slide table 201-2826 might fit this or a slightly larger drll press.  But to try and use the drll press as a milling machine the spindle taper needs to be MT2, not the JT33 like this 8" drill press.

The 201-2536 "Heavy Duty Mill and Drill Table" is 10 1/2" front to back and 8" wide, which it way too big to fit the 8" drill press.

The 201-2826"260-512PHSII Comp Slde Mill and Drilling Table" has a base that's 5 1/2" wide.  It may be an octagon that's 5.5" across the flats.  But how deep the mounting notches are would determine if it just bolts on.  This table uses 5/8" T slots, not 1/2" like the drll press.  The distance between the inside edges of the "T" slots on the 8" drill press is 3 5/8", so that's the minimum distance between the points of the slots in the base of the 201-2826.  Grizzly also sells this table as their H7979.

Harbor Freight 30999 4" Drill Press Vise

When turned 90 degrees you can get a couple of bolts into the two rear holes in the base.  But after placing a bolt in the rear of the table slot the other vise slot is hanging in the air in front of the table.  You can use C-clamps.
The movable jaw pivots on the end of the clamp screw.  That allows the jaws to grip things that are not parallel, but it also can be akward when clmaping other objects, like a sheet metal part.

What should work is the 2 1/2" Drill Press Vise (Harbor Freight 5927).

If I was shopping for a bench drill press today it would get the lowest priced one that had a MT2 spindle taper.  If in addition one could be found that had a quill lock that would also be good (It may be that the depth stop can be configured to act as a quill lock).  The MT2 is essential if you want to have a go at using the drill press as a milling machine.  The quill lock is also very important to allow sideways milling where the height of the cutting tool is supposed to remain the same.  An alternative to the quill lock would be a rack and pinion height adjusting system, but that's most likely more coarse than the quill adjustment.  The price difference is small and gives you more options.  The run out on a drill press is mostly in the 3-jaw chuck, not the bearings so switching to a collet system would allow more precision drilling.  This gets more important as the drill size gets smaller.

Lathe - my first look for a 5C collet lathe
Miniature Machine Tools - Seig and related small lathes & mills
Mini Cut-off Saw - for cutting material to fit 5C collet
8" Shear Break - tried to use for cutting 1/16" Printee Circuit Boards, but only works well for 1 or 2 inch cuts, not larger.
Fasteners - a handy table of threads that I use often
Flashlights - has some aluminum tube sizes related to cylindrical battery diameters
Length & Weight Measurements - tools
Pocket Tools - multi purpose tools
Electro Optical Gadgets - includes linear and rotation digital readouts

Harbor Freight -
Enco - note Use Enco is both their web page URL and their 800 phone number