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Vintage Craftsman 150 Drill Press - Restore/refurb

hman

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#1
About a week ago I bought myself a new project. It's an old Craftsman 150 drill press I saw at a Habitat for Humanity thrift store. Sold "as is," with a sign indicating the motor didn't work. Bought it for $25.

I posted a gloat on the Tool Junkies forum - http://www.hobby-machinist.com/threads/vintage-drill-press-score.49601/ - and it was suggested that I put my restoration/refurb posts on this forum. So here I am!

First off, photos of the DP as bought:
kHPIM4427.jpg kHPIM4428.jpg kHPIM4431.jpg
Vital statistics: The model number is 103.24530. Comparing features to catalog descriptions, I'm pretty sure it's catalog number is 99M2453N (floor model, sold without motor), from the 1960/61 catalog. The DP includes the optional "Vari-Slo" variable speed pulley system (Sears Cat #9-2340).

Initial disassembly showed that this DP is actually in very good mechanical condition. There's some light surface rust on the table and column, and just two small divot holes on the table. Other than that, no broken parts, nothing jammed or stuck, only the chuck key missing. I cleaned up all the internal parts and found two pairs of ball bearings (spindle and motor) that I thought were due for replacement. Ordered those from eBay. After removing everything from the castings, I gave them a pressure wash and rinse at a local car wash. Stubborn gunk was taken care of with Zep citrus cleaner.

New clamp ring: When first trying to remove the head from the column, I'd almost had a "woopsie" that could seriously damaged some parts. When I loosened the clamp bolt, I didn't have a good enough grasp on the head and it slipped downward. Part of the Vari-Slo mechanism extends over the column, and when the head moved downward, it ran the column into the mechanism. Luckily it didn't hit hard or cause any damage. But I decided I needed some kind of safety collar under the head to limit its downward travel ... just in case I or some future owner had occasion to again remove the head.

I started with a 5 lb cast iron dumbbell weight.
kHPIM4441.jpg
After covering the lathe ways I faced the outer section of both sides. Luckily, I could ignore the nasty scallops near the center, because that part would be cut away. The column of the DP is 2 ¾" diameter. I used a 2 ½" hole saw to make a rough hole, then finished it to the final size. I then offset the remaining ring by ¾", using three of the jaws of my 4-jaw chuck. There wasn't room for the fourth jaw, but I was able to hold the part securely with what I had. I used a 4" hole saw to cut out an eccentric ring.
kHPIM4442.jpg
After cleaning up the OD, I went to the mill to drill, tap and counterbore for a ¼" screw. Finally, I saw cut across the widest part of the ring.
kHPIM4446.jpg
kHPIM4444.jpg
The result is an easily adjustable ring that fits well on the DP column and can be clamped tightly in place.

-- to be continued --
 

hman

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#2
Motor testing: Because the notice on the DP said the motor did not work, checking it out was one of my higher priority items. As bought, the power cable and on/off switch cables on the DP had been snipped off. You can see some of that in the photos attached to my first post. Once I had the motor disassembled, I started checking each of the elements.

First off was the centrifugal switch. The mechanism looked OK. Couldn't spin up the rotor, but the springs and weights looked OK, and their motions were unimpeded. The switch itself had good continuity when closed, and infinite resistance when open. Just for fun I gave the contacts a good cleaning with some 600 grit sandpaper.

Second was the motor windings. Hmmm - the stator has 5 leads. I assumed that meant split run windings, plus a start winding (because it connected to the centrifugal switch and capacitor). The meters I had - an HF freebie with at least 1.5 ohms resistance in the leads, plus an analog meter whose lowest resistance scale was in k ohms - were of little or no help deciphering the three run winding leads. It did appear that two of them were shorted together, but I couldn't be sure. So I cobbled together a 110v AC test rig - basically, a pair of alligators in series with a 150 watt lamp. When connected across a good motor winding and you touch a screwdriver lightly to the motor poles, you can feel a slight buzz from the AC magnetic field. If the two leads are shorted, there will be no buzz.
HPIM4485.JPG
PS - If you want to build such a rig yourself, be sure to use an incandescent bulb (remember those?) of at least 100 watts. Energy efficient bulbs just won't do it!

Two of the leads were definitely shorted together. But it looked like they both went to the same place. Assuming I had nothing to lose, I carefully cut away some of the ancient, crusted tape over what looked like the right joint and discovered that both leads were soldered to the same motor wire. I guess it was done to make the many connections easier(?) Anyway, I re-insulated the joint with "liquid electrical tape" and declared the windings OK. I did add heat shrink tubing to all the motor leads, both to identify them and as insurance - the wires are rubber insulated and cloth covered. Though the original insulation seemed OK, such ancient rubber is not too flexible any more, so it's very easy to crack.

Next was the capacitor. The form factor and construction of the original capacitor is fascinating - a solder sealed rectangular metal box, about 3/4" x 3 1/4" x 5", slipped inside a cardboard sleeve. This shape allows the capacitor to nestle inside the motor base. No bulky cylindrical "warts" on the outside of the motor case for Craftsman! So I sincerely hoped that it would be good. A replacement of the same size and shape would probably be impossible to find nowadays!

An initial test with an analog ohm meter indicated that it was indeed acting like a capacitor.
[For those interested, make sure the capacitor is discharged by shorting the leads together. Connect across an analog ohm meter. The needle should immediately swing to somewhere in mid scale, then decay to infinite ohms as the capacitor charges. Wait a second or two and reverse the test leads. The needle should immediately peg at zero ohms, then decay back to infinite. If the needle does not go to infinite ohms on either test, or the second test does not peg the meter, there is probably a high resistance short in the cap. If the needle goes to low ohms and stays there, there's a low resistance short. If the needle doesn't move at all, there's an open.]

The question was, what value was the capacitance? I'd read that old capacitors slowly lose it, so I was concerned. Went to Radio Shack and found a very nice meter (SKU #2200075) for $45. It not only has capacitance, but also several other useful scales not normally found on meters. Plus the range of the capacitance scale (999.9 uF) was wider than that of a $70 meter they had. The nominal value of my capacitor would have been out of range on the other one. Tested the capacitor when I got home. It read 190.6 uF - smack dab in the middle of the value range (167-210 MFD) printed on the case. Golden!
kHPIM4468.jpg

Bottom line - I have every reason to believe that the original motor will run just fine, once I get the new bearings and reassemble it. Not having to replce the motor or add a clunky new capacitor will definitely help preserve the "vintage" look of this old veteran! I don't know why the DP was originally marked as having a non-working motor.

PS - Use caution when ordering bearings (especially Chinese) from eBay!!! I'd originally ordered the same bearing number as that originally on the motor (with a different suffix for shielded). The bearings I got did not fit (though they were somewhat close)! I went back to the motor and measured the shaft diameter and housing bore. They were different (metric) from the nominal sizes (inch) of the description on eBay, even though the numbers were the same. Did a new search, just for the metric ID, OD, etc. Found some matches and ordered a pair of these. Then, just for fun, I did another eBay search, based on the bearing number listed for one of the correct ones. Bleah! The hits I got for that number were for a different ID!!!
 

DoogieB

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#3
Usually if I'm buying bearings I get them MCM or another trusted source. You gotta watch some of the sellers on Ebay, sometimes they are cheap for a reason.

 

hman

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#4
Got the correct bearings in the mail today, so I completed the rewiring and reassembly of the motor. Gave it the blue smoke test ... IT WORKS!!! Durn, it feels good to know that the original motor will stay on this old classic!
 

wa5cab

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#5
hman,

Before you reassemble the motor, you need to run one more electrical test, a short-to-ground test. This would preferably be done with a megohmmeter (AKA Megger) but if you are careful and don't have any knob-twiddlers or other children around, you can use the AC line and an incandescent lamp (but I would use a lower wattage one than that floodlamp). Put the stator assembly into a large plastic bowl. Identify which contact in your wall outlet plug is the Neutral and which the Line. With the line cord NOT plugged into the outlet, connect the line cord wire that will be Neutral to the stator frame. Connect the Line wire to one side of the lamp socket. The other side of the lamp socket will be the test lead. Connect the test lead to either Run winding wire. Plug in the line plug. The lamp should not glow, even dimly. Unplug the line plug. Connect the test lead to either side of the start winding (assuming that the capacitor is still disconnected). Plug in the line plug. The lamp should not glow. Unplug the line plug. Disconnect the Neutral wire from the stator frame, and replace the stator in the bowl with the capacitor. Connect the Neutral wire to the metal case of the capacitor. Connect the test lead to both capacitor terminals. Plug in the line plug. The lamp should not glow. Unplug the line plug.

EDIT: I was writing this while you were writing the above. Apparently you got lucky. But I wouldn't have bet on it, given that the motor had been reported as bad.
 

hman

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#6
Robert -

You're absolutely right about the importance of short-to-ground testing!

Once I had the motor disassembled, I did an initial test with my HF DVM. I did it again, using the new meter I'd bought, after I had the motor reassembled and the wiring completed. As mentioned in my previous, I was concerned that flexing the old insulation might break it and expose a wire. I was also concerned that I might have unknowingly pinched a wire (old or new) between parts of the motor housing. The new meter auto-ranges up to megohms. Checked each end of both windings, plus both sides of the line cord, to ground before closing the connection area cover. Everything was open to ground. I also did a quick-and-dirty instrument check, holding a test lead in each hand with relatively dry fingers - about 6 megohms.

I do like your test method and thought of a simple variation, using a volt meter - Connect a winding in series with the bulb, as in my test above. Then connect one side of the volt meter (set to the most sensitive AC scale available) to the motor case and probe both ends of the winding. Should read zero! Test the other winding the same way ... likewise the capacitor.
 
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wa5cab

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#7
No, that won't work the same. Mentally simulate a short at one end of the winding by connecting the lead wire coming out from that end to the frame. You would have a hard short to case but no reading on the meter with the meter lead connected to the frame and that end of the winding. You would get a small reading with the meter leads connected to the wire for the other end and the frame (where the cold end of the lamp would be connected due to IR losses in the winding since the flood light would be drawing around 1.25 A and there would be a small drop in the motor winding.
 

hman

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#8
Hmmmm ... gotta think about this some more. You're definitely right about a hard short ... though it should find high resistance shorts quite efficiently. And of course, a hard short to the motor case is very easy to find with even a junky ohm meter and no additional hardware.

One reason I went off on this tangent to begin with is your saying to look for the lamp to glow. I don't think a few volts or a few milliamps will cause the filament to glow at all. I forget the actual value, but I think something like 5 milliamps is where GFCI devices pop.
 

hman

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#9
Painting: There are several blogs having to do with restoring these drill presses. Whenever they mention paint, it's Rustoleum Hammered Bronze. Unfortunately, I don't think it's available any more - tried several stores, couldn't find that color. So I bought the three rattle cans that seemed to be closest to the right color. Painted up some aluminum coupons and set them on the DP head to compare:
kHPIM4452.jpg
The uppermost (Rustoleum Universal Metallic "Champagne Mist") looked to be the best match. It's a bit more golden than the original, but it's pretty close - and without the original on hand for comparison, it'll surely get by.

Masked off the holes and hit all the castings with at least one coat. The head got one coat inside and two outside.
kHPIM4489.jpg kHPIM4478.jpg
I left all the parts out in a sunny spot to dry for a couple days.

Spindle reassembly and test
: I started reassembling the drill press today. I was most concerned with possible runout in the spindle and chuck, so I did that assembly first (using the new bearings I'd ordered from eBay). I mounted the spindle sleeve in the lathe chuck - not to spin it (the lathe was not under power), but simply because the lathe chuck and carriage were handy to hold things. Mounted a ½" Thompson rod in the drill chuck. Used an Interapid .0005" DTI and checked the runout at 1", 5" and 10" from the DP chuck (rotating it by hand.)
kHPIM4492.jpg
ALMOST UNBELIEVABLE! Runout was 0.0010" at 1" and 10", 0.0025" at 5"! I think I mentioned earlier that all the parts I'd taken from the drill press looked to be in very good mechanical condition ... but WOW!
 

wa5cab

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#10
Hmmmm ... gotta think about this some more. You're definitely right about a hard short ... though it should find high resistance shorts quite efficiently. And of course, a hard short to the motor case is very easy to find with even a junky ohm meter and no additional hardware.

One reason I went off on this tangent to begin with is your saying to look for the lamp to glow. I don't think a few volts or a few milliamps will cause the filament to glow at all. I forget the actual value, but I think something like 5 milliamps is where GFCI devices pop.
With that frosted face 150W flood lamp, I'm sure that you are correct. I should have been more specific and said to use an unfrosted (clear) bulb 12.5 or 15 Watt lamp.

However, assuming that you are using a three-wire plug in a properly grounded outlet, as it hasn't tripped the breaker yet, it is most likely alright.
 

hman

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#11
With that frosted face 150W flood lamp, I'm sure that you are correct. I should have been more specific and said to use an unfrosted (clear) bulb 12.5 or 15 Watt lamp.

However, assuming that you are using a three-wire plug in a properly grounded outlet, as it hasn't tripped the breaker yet, it is most likely alright.
You did say in your initial post that a smaller bulb should be used, and I agree that a 150 watter would be totally unsuitable. But I know that even small bulbs need more than a few volts to even give off a glow. So just for fun, I connected a 5 watt Christmas tree bulb (remember these?) to a precision (DC) power supply I have.
kHPIM4500.jpg
Results were as follows -
10 volts - 0.0003 amp (0.003 watt), no glow visible, even in a totally dark room
12 volts - 0.0011 amp (0.0132 watt), glow barely perceptible in totally dark room
15 volts - 0.0026 amp (0.039 watt), glow visible in dark room, not visible with reading light on
20 volts - 0.0040 amp (0.08 watt), slight glow visible with reading light on.
I'd have gone to higher voltages, but 20 is the limit of the power supply.

If you look very carefully, you can barely see the W-shaped filament glowing in front of the gray panel of the power supply. The brighter yellowish ring-shaped glow near the top of the bulb is a reflection of the reading light. Obviously, the glow would be more visible with just a reading light than with the flash from the camera.

Anyway, I simply don't think a light bulb is a sensitive enough instrument to be very useful in this application. Yes, it's a slightly better than nothing. But I think we're both safety conscious enough to agree that this isn't an area where you want to fool around with half measures. You really need some kind of a meter with a scale.

The best solution, as you'd originally said, is a megohmmeter.

Or else, as I'd suggested, use a voltmeter on its most sensitive scale to look for high resistance shorts (after checking for hard shorts with your method and any kind of bulb). Though not ideal, it's workable. Movement of a scale is much easier to spot than a faint glow.
 
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wa5cab

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#12
I didn't mean to start an argument over this. Two things.

First, in the beginning, as far as I could tell from what you wrote, you didn't own any decent test equipment. And if you did, I had no way of knowing whether you knew how to use it. I could see that you had a lamp socket and some alligator clips. So I suggested that method as it was simple to explain and the only additional component that it required that I wasn't sure you already had on hand was the small standard base lamp.

Second, the nature of inadvertent shorts is to be intermittent, to sometimes behave as low quality semiconductors, and typically to be difficult to find with a low voltage analog ohmmeters and much more so with digital ones. Unless running current through the point of contact welds the two pieces together. Plus high impedance voltmeters can be fooled by shunt capacitance in the pfd range. Using the 120 VRMS AC line guarantees a minimum voltage from the run or start winding to case of 85 V peak at the midpoint and higher than that toward each end.

Anyway, as I said earlier, the fact that it's running satisfactorily would seem to indicate that the report of a bad motor was false. The problem could have been in the external wiring. Or even in some of the internal joints that you opened up and then re-taped.
 

hman

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#13
I didn't mean to start an argument over this.
No problem. Nor did I think it was an argument. I figured we were simply batting ideas back and forth, with the common goal of a thorough safety test methodology.
Anyway, as I said earlier, the fact that it's running satisfactorily would seem to indicate that the report of a bad motor was false. The problem could have been in the external wiring. Or even in some of the internal joints that you opened up and then re-taped.
I think it was indeed the external wiring (which was snipped off short in several places. My best guess is that the original owner (or his heir?) saw some of the old insulation in bad shape, and decided to cut it away for safety's sake before donating the drill press. But who knows????

Anyway, I think I lucked out in finding everything as good as it was.
 

hman

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#14
OK, back to the rebuild ...

Quill tensioner: The quill return spring in this Craftsman is quite unlike the ones used in most modern drill presses. Instead of a flat coil in an external "cheek," it has a coiled wire spring inside the hollow shaft of the feed handle. An external knob on the side opposite the hub sets/adjusts the spring tension and a thumb screw underneath locks the setting.
kHPIM4429.jpg

The end of the lock screw is pointed, to improve its gripping power on the adjusting knob. But even with a point, the grip strength of this lock screw was pretty low. I found that pliers were needed to tighten the lock screw enough to get a good lock. The original owner probably did the same, as the mating surface on the tension knob was already marred in several places.

I decided to remedy this situation by adding a series of dimples around the mating surface of the tension adjuster. The photos show my mill setup and the result (which works well). A pointed rod in a Noga-style indicator holder engages the flutes of the knob, creating a makeshift indexer and allowing placement of the dimples at equal intervals.
kHPIM4465.jpg kHPIM4466.jpg

Vari-Slo assembly: Unlike other parts of the drill press, the Vari-Slo speed control assembly did have some signs of wear. A hole in one of the links was egged out - possibly from the assembly having been displaced from its original location. There was also a part missing - a plastic clamping pad that originally went between the steel adjusting/position locking knob and the soft aluminum face of the adjuster frame.

I found a piece of K&S brass tubing of the right ID to use as a repair bushing, drilled out the hole to fit the OD, and used JB Weld to hold the brass in place and fill the oval around it.
kHPIM4462.jpg

After the epoxy had hardened, I filed down the ends of the brass tube even with the surface of the aluminum casting.
kHPIM4471.jpg

As for the clamping pad, I only had some sketches from the installation manual to guide me. But nothing looked very critical. I turned the end of a piece of UHMW rod to fit into the threaded hole of the adjuster, then turned a 1/8" length to as large a diameter as I thought would fit the available space. After parting off, I cut a flat on the flange, so the pad would fit under the bar of the adjuster.
kHPIM4503.jpg
kHPIM4507.jpg

Final assembly and table tram check: Using my downloaded copy of the Vari-Slo manual, I installed this and the otherwise completed head onto the drill press post. The photos show the completed assembly. Everything works!!! The Vari-Slo does a nice job of setting the spindle speed anywhere from ~300 to ~3750 RPM.
kHPIM4510.jpg kHPIM4511.jpg
PS - the red object on the right side of the motor is a toggle switch with a Radio Shack shield over it. It's a reversing switch. I really don't have any plans to run the quill backwards, and it has no effect when the motor is running (reverses the start winding!), so it's not too handy for tapping. But there was such a switch on the motor when I bought the DP, so I decided to keep it for authenticity's sake.

As a last hurrah, I checked the table tram. Because the table is not adjustable for tilt, I expected it would be pretty square to the spindle. Wow again! It was off just 0.009" front-to back, and 0.003" side-to-side on a ~9" circle. Even better, pressing downward on the table (say for a heavy drilling job) would improve the squareness as it flexed!
kHPIM4497.jpg kHPIM4498.jpg

Anyway, that's it for the refurb. I enjoyed it all immensely, and again think I was extremely lucky to find such an oldie in such fantastic shape!
 
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wa5cab

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#17
John,

That is very nice work you've done. But I have to give a mia culpa here. Another member, whose ID I didn't look at long enough to recall ten seconds later, posted a similar kudo but somehow two copies showed up. I went to delete the duplicate, then noticed that it had a Like and deleted the first one instead. Unfortunately, I forgot to UN-CHECK the duplicate and it got deleted, too. I can't remember whose post it was but their avatar is a side view photo of a light green Atlas MF(*). So if that individual happens to read this, please re-post.
 

Silverbullet

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#19
Beautiful press, you my friend are very lucky to find that press for such a paltry sum of money. Good luck with a gorgeous drill press. Reading this was like watch two shop teachers correcting a student or apprentice . I look at the vari speed but can't see how it works. Dose it use clutches ,, Phillies,,, that slide open and closed??? Thanks just interested in the how it works.
 

hman

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#21
Beautiful press, you my friend are very lucky to find that press for such a paltry sum of money. Good luck with a gorgeous drill press.
Thank you. Sold it to a friend nearby (Rick Sparber, a member of this forum) for not-too-much. He's added a counterweight to the table.
Reading this was like watch two shop teachers correcting a student or apprentice . I look at the vari speed but can't see how it works. Dose it use clutches ,, Phillies,,, that slide open and closed??? Thanks just interested in the how it works.
The variable speed is accomplished with variable pulleys. This Youtube shows how a single pair of variable pulleys works:
See also "CVT" (continuously variable transmission).

The drill press takes this idea to a higher level, with two sets of "paired" variable pulleys. See post #14 for photos.

The speed adjuster changes the spacing between the (fixed width) spindle pulley and second pulley set. Changing the spacing causes the V-belt to ride inward or outward in the lower section of the second pulley. The outer flanges are fixed, so it's the middle "flange" that moves up or down. The driving diameter of the second (upper) belt is therefore changed in the opposite manner.

The spacing between the second and third pulleys is fixed by the lower and upper bars. As the belt moves inward or outward in the second pulley, it moves inward/outward in the third pulley, in turn changing the position of the middle flange and the driving diameter to the third (motor) belt. The motor pulley has a fixed diameter.

Both ratios increase and decrease together, multiplying/amplifying the effect of adjustment changes. The overall ratio can be varied by a factor of 12 (300 to 3750 RPM at the spindle).

It's a bit hard to explain in words. Shoulda taken a video! Watching it run would get the whole idea across pretty quickly.
 
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Silverbullet

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#22
Thank you. Sold it to a friend nearby (Rick Sparber, a member of this forum) for not-too-much. He's added a counterweight to the table.

The variable speed is accomplished with variable pulleys. This Youtube shows how a single pair of variable pulleys works:
See also "CVT" (continuously variable transmission).

The drill press takes this idea to a higher level, with two sets of "paired" variable pulleys. See post #14 for photos.

The speed adjuster changes the spacing between the (fixed width) spindle pulley and second pulley set. Changing the spacing causes the V-belt to ride inward or outward in the lower section of the second pulley. The outer flanges are fixed, so it's the middle "flange" that moves up or down. The driving diameter of the second (upper) belt is therefore changed in the opposite manner.

The spacing between the second and third pulleys is fixed by the lower and upper bars. As the belt moves inward or outward in the second pulley, it changes the position of the middle flange in the third pulley, and in turn the driving diameter to the third (motor) pulley. The motor pulley has a fixed diameter.

It's a bit hard to explain in words. Shoulda tooken a video! Watching it run would get the whole idea across pretty quickly.
Ok that explains it it has two sets of sliding pulleys good stupid spell Ck wrote Phillies .