Delta 15-665

[rwdenney]

Quoted from the What Did You Buy Today thread:

The craptastic “Clarke” import drill press I’ve been suffering with for 20 years was the subject of a POTD where I put the spindle in the lathe and remachined the JT3 taper on the removable arbor to get rid of the 0.060 (!) runout. I improved it to 0.006, measured while still in the lathe. Back in the press, it was great for a while. Now, the runout is back up to 0.035, measured on a 0.450 gauge pin in the chuck. Belt tension bows the spindle, which only runs on two bearings and carries the pulley, and the quill is short and narrow.

So, I’ve been looking for a better drill press to replace it. Last week I tried to buy a Walker-Turner WT-900 press from about 1950 that was on FB Marketplace, but, as usual, couldn’t get there quickly enough and someone else grabbed it.

I had looked at a new Jet, available locally for about $1600, and a Powermatic that was even more than that. Uh, no. Even if they are great, that’s too much to spend on a mere drill press when I don’t yet have a mill.

But I did finally decide I was going to have to pay eBay prices for a vintage American-made press, just so I could actually buy it.

I looked at Walker-Turner, Buffalo, and Delta. I saw a Buffalo Model 18 that was appealing, but I’d have to drive 150 miles to get it and the price was still in the upper three figures. And who knows what it would need, being 70 years old and a bit derelict.

I didn’t want a 17-20” press with power feed and all that. I want something I can move around and I just don’t need to drill 1” holes in steel. And I didn’t want to spend mill money.

Finally, I bit on a 15” Delta, a 15-665 from 1970, which is the 6+6 model with six speeds and 6” of quill travel. It’s a bench model mounted on a sturdy steel table that had come out of a fab shop in Baltimore. I thought it might be too light, until I compared it to what I have, and before I’d read up on the model from documentation on Keith Rucker’s site and testimonials here and on other forums.

My Tractor Supply special has a 3/4-HP motor, a 5/8” chuck, and speeds down to 280 RPM. The Delta has a 1/2-HP motor, a 1/2” chuck, and a single-belt drive with a lowest speed of 450 RPM. But look again: the import “3/4-HP” motor draws 7.4 amps, and the Dayton motor on the Delta draws 8 amps. Typical HP fiction.

The lowest speed of 450 is the only complaint. In every other dimension, the Delta blows the doors off the import. I was able to inspect it under power today before buying it, and I took along a dial indicator. TIR is 0.0035 on the side of that 0.450 gauge pin. That’s even a bit better than Jacobs’s claim for the 34-33C chuck, which is rated at 0.004.

The Delta is much heavier, and it made me realize that my old one didn’t really earn that 5/8” chuck capacity.

And the old Delta is smooth. The pulleys are balanced and even at the top speed of over 5000 RPM there is no vibration. The old one dances around at its top speed of 3100 RPM, in part because it’s too light.

The table needed stoning badly, but tramming it after that required only two taps of a deadblow and retightening the tilt bolt to get the table within 0.002 of perpendicular in both axes using my dual-indicator tramming fixture.

It has a table, unlike most bench models, which makes up for not having anything to assist raising the head. I might add that at some point to take advantage of the t-slots in the base casting.

And I might install an 1140 RPM motor for the rare occasions when I need to use those S&D drills in steel.

And I wondered what I was giving up not have a Morse-taper spindle. But the chuck is clamped to the JT33 taper using a screwed collar, which I have decided is a better arrangement. I’ve certainly never used anything but a chuck in the old press.

The Delta push-button on-off switch has been replaced by a forward-reverse drum switch. That was a big selling point for me—this press should be able to do power tapping within reason.

View attachment 472683

I had to use a hoist to get it off my trailer—the press and its table easily weighs 300 pounds. The table top is 3/16 plate on angle legs.

Now to find casters for it that flip down onto solid feet.

Rick “test drilling tomorrow” Denney

I can't resist the temptation to record what I have learned about this drill press, but that thread isn't for that. This is a popular press in the wide world, so I thought some detail might be in order for posterity.

I installed kick-up caster wheels from Woodcraft onto the table. These are intended for workbenches, but I drilled and tapped the legs for 3/8 machine screws (what I had handy) and they serve the purpose of making the table movable when necessary. But these casters are rated at 110 pounds of load each, so putting the first one down overloads it. One has to be a bit cautious. Once the second one goes down, the table is always resting on at least two of the casters, which only overloads them slightly. I'm assuming (perhaps foolishly) that they are designed for this eventuality, given that they talk about how four of them can carry 440 pounds. The table and press combined weights probably 275 pounds, and given that it will not be resting on the casters except when I want to move it, which will be rare, I'm not yet worried. All my machines except the lathe are on kick-up wheels or wheels with screw-down feet so that they can be moved. (While at Woodcraft, I looked at the Powermatic drill press they had there. It's quite nice, with a Reaves-drive variable speed and a 3/4-HP motor that is about the same actual power as what this press has. I didn't measure it, but I don't think it's as large as the 17" Delta, but it may be a bit beefier than this 15". It's also $2000.

Let me talk a bit about the model number: 15-665. That number is quite commonly found on Delta's 6+6 and VS (variable speed) 15" drill presses, yet good luck finding that number in any of the Delta literature. Why that number isn't in any of the period catalogs is anyone's guess. It's a benchtop model with the standard tilting table and the arbor with the JT33 taper on the end and the Jacobs 33-34C chuck. According to the Rockwell Delta Industrial Machines catalog from 1970, this model should be the 15-491:

(clipped from http://vintagemachinery.org/pubs/1141/7336.pdf on Keith Rucker's site.)

But perhaps there is a fresh order number when a motor is installed from the factory. I'm not sure, however, that this drill press has a factory motor--Rockwell usually used Marathon motors during this period that were given their house label, not Dayton motors like mine had. And on mine, the pushbutton on-off switch has been replaced by a Dayton forward-reverse drum switch that likely came with the motor.

The base casting includes 1/2" T slots and a blanchard-machined surface that is actually pretty flat, but that isn't much use for the non-production model because moving the head up and down on the column is no mean feat. The head along weighs 72 pounds according to the chart, and with the drag on the column and the height above the floor is quite difficult for me to lift. I had lowered the head to transport the press but ended up using a toe jack to push it back up to the top of the column. For this reason, I found and ordered from ebay an accessory that came with the production model. It comprises a long spring that compresses as the head is lowered, suspending the head using a roller chain that feeds over a pulled mounted at the top of the column. I think this will be a handy addition.

(from ebay ad)

The chain is connected to a rod with a spring retainer held to its end by a nut. That chain goes up through the spring, compressing it against the pulley fitting that inserts into the top of the column. It hooks onto a connection on the top of the head casting. I have no idea how well it will work, but even if it lifts half the weight of the head, moving the head up and down after swinging the table out of the way will allow one to drill to items clamps to the base casting.

The table itself has 1/2" slots and also access to clamping surfaces on the sides, but I never seem to have the clamps I need to lock things down. This table screams for a float-lock vise, which is definitely on the agenda. Even though this drill press is in the fractional-horsepower category, that does not relieve one of the requirement to firmly clamp down workpieces. I used the drill press to enlarge the holes in the caster frames, and I applied quite a lot of tool pressure to make sure the drill fed properly. The motor didn't even slow down. There is definitely enough force to pull a workpiece out of one's grip, swing it around, and damage the hand that just let it go.

In the next post, I'll talk about chucks, speeds and metal-working, which are always topics relevant to smaller and older American drill presses, especially from companies most known these days for woodworking equipment.

Rick "more to come" Denney

 

[rwdenney]

So, is the 15-665 suitable for metal work?

First off, Delta sure thought so. Delta included three sizes of full-featured drill presses, plus 15" utility and 14" high-speed sensitive drill presses in their industrial catalog. The 17 and the 20 included optional power feed. The 20 included the option of a geared spindle with speeds down to 110 RPM when using an 1140-RPM motor of 1 or 1-1/2 horsepower. But the maximum spindle speed for these models topped out at 1800 RPM (when using the 1725-RPM motor), so it's great for big holes, not so much for small holes, particularly in soft metals.

The 17 came with 5-step pulleys in two sizes, one for high speeds and one for low speeds, either of which could be used with 1140 or 1725-RPM motors. The slow-speed model with the 1140-RPM motor runs the spindle from 255 RPM to 1475 RPM. The variable-speed model could go slightly slower, but much faster, up to 2800 top speed, though that's it. The high-speed stepped-pulley model could go to 4250 RPM, but only with the 1725-RPM motor. The 17 used 1-HP motors.

Clearly, both of these get usefully slow for holes of moderate size in hard metals, but not so much high speeds for small holes in soft metals.

The 15" deluxe models used either 6-step pulleys or a reaves-type variable-speed drive, but with no option for power feed. The pulleys provide a 12:1 speed range, which is the largest I've seen without using an intermediate reduction pulley. My import drill press used an intermediate pulley to get speeds from 260 to 3100 RPM, which is also a 12:1 range. I suppose one could make it slower with an 1140-RPM motor (or a three-phase motor with a VFD), but I don't think the machine is stiff enough for the sizes of holes those lower speeds would imply. More on that in a moment.

(Speaking of the import press, I investigated it a bit further this afternoon. My improvement in it by machining a custom JT3 taper on the end of the arbor to correct for the runout of the spindle was still effective, as it turns out. But the quill was loose in the head and there is no way to tighten the head to accommodate that wear. It had loosened up enough to permit 0.010 of rattlingly loose end play. And, of course, the MT2 end of the arbor can only go in the quill one way for the correction to hold up. Embarrassingly, I had installed it backwards in the quill after it had fallen out after a hole had gone sideways, and that's why the runout had jumped up. But all holes in hard metals will chatter like crazy and that loose quill is the reason. That also means no MT2 accessory can be directly used without restoring the 0.060 runout, plus the end play. Junk is junk, but I'm sure it's fine--with my correction--for drilling bolt-clearance holes in wood or soft metal.)

The slowest speed of the 6-speed model when using a 1725-RPM motor is 425 RPM, slow enough to provide 56 SFM in the rated 1/2" drill for hard metals. This is slow enough for drilling holes in (pre-hardened) tool steel, but not slow enough for hard-chilled cast iron or stainless steel, both of which would prefer about half that SFM, according to Norseman's recommendations for their HSS drills. The highest speed is 5500 RPM, which is really fast for a drill press. That's fast enough for a 1/8" hole in aluminum without compromise, though I've certainly gone slower than that in aluminum with workable results (meaning: I'd rather compromise on the high end rather than the low end). The claimed maximum runout of the Jacobs 33-34c chuck mounted on this drill press is 0.004", so I wouldn't really want to use a smaller drill than that anyway. Smaller drills than that are the domain of high-speed sensitive drills with collets or higher-precision small chucks.

But I do occasionally drill larger holes than 1/2" in steel, at least in mild steel that wants 80-100 SFM with an HSS drill.

So, I have two options: The usual recommendation here is to install a three-phase motor with a VFD. But I can't find a way to make that happen for less than about $300 even using used or import-grade stuff. One alternative is to mount a DC motor, such as the high-HP motors used in treadmills. But that becomes a project of some significance--those motors certainly do not come in a 56-frame form factor and so the entire mounting would have to be fabricated.

But I did find this on ebay:

This is a 1/2-HP, 56-frame, TEFC, 120VAC, single-phase, 1140-RPM motor that was used and that I picked up for about $71 (plus a formidable shipping charge). It pleases me that this is a Marathon motor, given that Marathon was the usual supplier to Rockwell for their house-branded motors supplied with Delta machine tools. Granted, it's a bit too new to look right on a 1970-vintage press. Maybe I'll regret the choice. It uses sealed ball bearings and while it is not rated (I don't think) for vertical service it is certainly capable of it for intermittent use in a hobbyist drill press. Current draw is a bit higher than the current Dayton motor on the press at 9.6 amps, so I think it's not so new (or so import) that the HP rating is complete fiction. Plus, the 1/2-HP 1140-RPM motor will develop the same rated and breakdown torque as a 3/4-HP 1725-RPM motor, which is the maximum Rockwell recommended for the Delta 15" drill press.

This motor's specs are listed by Delta for application with this drill press, and furthermore they recommend the 1140-RPM motor for "drilling holes up to the maximum capacity of the machine". The speeds Delta claims range from 280 RPM to 3635 RPM. At the slow end, that should permit increasing the hole size to 3/4" at the same 56 SFM that the higher speed motor provided for a 1/2" drill. That's probably stretching the capability of a half-horsepower motor in any case. Again, this is adequate speed for pre-hardened tool steel, and it should be much more in the comfort zone for stainless up to nearly that size. At the high end, a 1/8" bit will provide 120 SFM--not too terribly slow for soft metals.

Rick "quickly turning a $500 press into a $750 press, but it's still a lot cheaper than $2000" Denney

 

[rwdenney]

Finally (for this week--travel tomorrow), a couple of bits and pieces about chucks.

Like most American presses in this size range, the spindle came in two forms. The most common form was a solid spindle with a JT33 taper on the tip. Further, the taper included a collar that would allow a threaded clamp ring to reinforce the chuck mounting. This clamp ring uses a special pin spanner to remove it, and, like the taper drifts supplied for morse-taper spindles, this spanner is rarely included with the drill on the secondary market. And such is the case here.

But I was able to find the correct spanner from a Delta tool parts supplier, the 15-838 Spanner. Mr. Pete showed a video where he made a tool, but this was easy enough to find.

The collar is roughly 1-1/2" in diameter and uses a 7/32" pin, if you want to make one.

Some complain that the chuck is cheap because it's a plain-bearing chuck. I have ball-bearing chucks and plain-bearing chucks, and find that this doesn't distinguish between good and bad chucks. Runout and jaw quality make a much bigger difference, and here the old Jacobs 33-34C chuck supplied for the solid spindle is quite good in the grand scheme of things. Jacobs still sells the chuck, but now it's made in China.

Of course, any JT33 chuck can be used, using the lock ring only as a removal device. But the clamping design is really nice. I've had chucks eject themselves in unusual drilling situations in the past, but this one won't do that. And I think it's a necessary feature for power tapping, which this drill press is capable of doing up to maybe 3/8-16 thread sizes in mild steel. (And that's where the forward-reverse switch that came on this one is a really nice thing.)

On the topic of runout. In a post above, I talked of high runout on my import drill press, particularly from a loose quill that can't be tightened. Like all good drill presses, the Delta has a clamp bolt that will squeeze the head casting slightly to take up any lateral play in the quill track. (This is, of course, separate from the quill lock clamp that bears on the same gap in the head casting.) I adjusted that so that the quill moves smoothly, but only just. There is no looseness at all that I can feel. But I can pull the chuck perhaps 0.005" out of alignment just by giving it a yank. Is it the quill? No--that measurement is the same whether the quill is retracted or extended, even if it is locked with the quill lock. Likewise, deflection in the head casting or column isn't likely, either, because that would be different with quill extension. So, it is probably deflection in the 5/8" spindle between the quill bearings being reflected at the chuck. And this is the difference between a mill and a drill press, even more than differences in the head casting and the table. Mills have much stiffer spindles that are larger in diameter--a requirement of having a through bore for a drawbar if nothing else.

Without that lateral force, the free-running runout on this Delta is 0.0035", which is quite respectable for a drill press.

Delta also supplied their drill presses with morse-taper spindles on request, but they are not common to find. They do sell an adapter, however. It attaches to the JT33 taper using the same collar clamping ring arrangement as the Jacobs 33-34c chuck, and provides an MT2 socket below that for tanged MT2 tapers. This isn't ideal, given that any lateral force on the drill will cause even more deflection in the spindle. Don't do milling with a drill press. And that adapter is freaking expensive, when you can find it. If you want a drill press for your collection of vintage MT2 drills and boring bars, this wouldn't be the drill press you'd want anyway.

Rick "everything you never wanted to know about the Delta 15" 6+6 drill press" Denney

 

[C-Bag]

This is of interest to me because I have a Delta 15-650 and would love to be able to get a much slower speed for large drilling. This is complicated by the fact mine is on a UniDrill base with a radial arm so it’s tough to find a motor that can clear the radial arm as it needs to be very short. Right now it goes from 450rpm to 4700rpm with the reeves drive and a 1750 motor. So not the best for metal IMHO and I’m not a woodworker. With a 1140 motor it would only drop to 300 on is slowest setting. I wish for more like 150rpm. I don’t do many super small holes so anything over say 1800rpm is a waste.

 

[rwdenney]

If I needed 150 I’d be looking for a 3-phase motor to run with a VFD. I saw many fractional horsepower 1140-RPM 3-phase motors—those seem to be more common than single-phase versions. Whether they are inverter-rated is a whole other question, but I’m out of my expertise on that issue.

There was an intermediate-pulley slow-speed kit for these, but they seem to be scarce. A guy on eBay is selling something similar that might work also. It isn’t that cheap but it’s cheaper than a motor. His kit only supports 4-position pulleys, however, not the six speeds my drill press has.

Do you think the Unidrill configuration has the frame stiffness to handle low speeds (and high torque) with large drills? I’ve never seen one up close.

Rick “doesn’t even own a twist drill bigger than 1”” Denney

 

[C-Bag]

There are so many variables to this I’m overwhelmed. The motor has to be very compact/short and most of the motors I see on eBay are posted by bozos with minimal info. I also don’t know what I’m looking for as far as a 3ph rated for vfd. The DP works as is and is handy as a shirt pocket so this is a back burner wish where I’m just keeping my eye out for info as it comes.

If it was one of those regular pulley systems I could figure out a 3rd pulley but mine is a reeves drive. So the only way to change speed is change the motor or swap with someone who has 15“ pulley type head. The mast and arm can do hd work now that I’ve over hauled the lock on the head. This type of radial arm has way more to it than the lower models I’ve seen but is not as beefy as the beam type radial arm which in this size range I’ve only seen one and it was an 80’s Enco. Radial arm DP’s in this size are not common.

 

[rwdenney]

The motor labels don’t always have everything on them, such as whether a motor is rated for any orientation. I end up having to find the motor on the manufacturer’s site, which isn’t always easy.

My second-hand understanding is that 3-phase motors that are rated for “inverter” operation are preferred for use with VFDs.

But I don’t know how much of this advice applies to intermittent hobbyist use versus all-day-every-day professional shop use. I suspect that and motor with sealed ball bearings will work in vertical orientations, whereas sleeved motors, and obviously if they use oil cups, are horizontal only. A drill press doesn’t apply a heavy axial load, and I put a lot more axial load on my 1-HP bench motor that I use for buffing. But that’s easier to understand than tolerating VFDs.

Rick “paid less for the slow motor than for a cheapie VFD” Denney

 

[rwdenney]

I was on the road this last week, and will be on the road again this coming week, but when I got back the bits I bought were waiting on me. No time to install, but I did get a good look at the motor.

When I had looked up the motor number, I apparently wasn't looking at the specifications for this particular variation. Motion Industries states the Marathon 56B11F5303K motors are fine for horizontal or vertical mount despite the "F1" mounting designation. The bearings used are (common) 6203 bearings, which are sealed deep-groove ball bearings that SKF rates over 1000 pounds static load and allowable axial load of half that, or 500 pounds. I'm thinking in drill-press service, the axial load is the weight of the rotating bits on the motor plus the drive pulley, which might be as much as 20 pounds dripping wet. I'm not worried.

Baldor motors use the same bearings in their similar motors, which are priced about the same as well. (About $1000 if you buy it from Motion Industries, which I suspect none of us would do).

I add this because people ask often whether any given motor can be used mounted vertically in a drill press, but good luck finding a 56-frame motor with a base mounted specifically designated for wall-mount (vertical) service.

And this puppy is no dainty thing. It dwarfs the "3/4 HP" motor on my old drill press, and is even bigger than the 1/2 HP Dayton that came on the press. But I suspect the six-pole 1140-RPM motors are necessarily somewhat larger.

Anyway, I'm looking forward to getting it mounted.

The head counterweight kit also arrived, but I only had time to look in the box. And the 1-1/2"x7/32" pin spanner that I bought from McMaster arrived, and it's made by Martin Tool Company, probably in Fort Worth, and that brought me no displeasure.

Rick "to be continued" Denney

 

[C-Bag]

I’ve gotten so burned and so deep in these rabbit holes I don’t jump until either some too good to pass up opportunity shows up or I finally get all the esoteric info I need. Like somebody with exactly the same thing does the exact mod I want to do.

You keep uncovering parameters I hadn’t even thought about like the vertical mounting. Might that be in the string of letters in serial or model #? But trying to uncover the meaning of that string of gobbledygook gives me a headache just contemplating it. I went through that when trying to find application parameters for guided pneumatic cylinders.

I do appreciate you documenting this as it is as enlightening as it’s cautionary

 

[rwdenney]

I just googled the motor number and up came the fact sheet from Marathon, plus the sale listing at Motion Industries that reiterated most of that information. Figuring out which part of the model number is really the model number requires a bit of trial and error sometimes.

Motor model numbers from the American motor makers seem to survive the ages. Even the 60-year-old Dayton 5K482 motor in my lathe still has lots of current information available.

Rick “research is part of the hobby” Denney