Purchased an 18" Delta Scroll saw, not working properly at an estate sale for $12.50. This saw must weigh 80 lbs. Model 40-650C type 1 Q3, only serial no. I can find is on the motor but there are what I think is French words on the motor and saw arm. Saw will run in High but speed control does not work. Research and testing identified a bad speed control module, not the potentiometer it tested good). Found a new original on e-bay and have it on the way. My issue is I cannot figure out how to attach a saw blade, maybe I am missing parts? I downloaded manual but pics and instructions are vague. Before I post pics, does anyone have this saw, I need guidenance other than I bought a very large paperweight, more like a pontoon boat anchor.

Heres the manual from the national archives Check page 12

7429679.pdf

$12.50?! Oh, wow! Those old Delta scroll saws are tanks. On the blade issue, that model uses clamp-style blade holders, so you should have an upper and lower clamp that pinch the blade (either with a thumb screw or Allen screw). If you’re not seeing a way to secure the blade, there’s a good chance the holders are missing or incomplete. They’re small and often get lost. Also check if it’s set up for pin-end vs plain-end blades, since that changes how it mounts. Once your speed control is fixed and the clamps are sorted, it should be a great runner.

Found this, not sure if it will help. Last post in the link

https://forum.scrollsawer.com/forum/scroll-saw/tools-and-blades/19760-need-part-for-delta-scroll-saw-40-650-q3-type-1

You have a Delta Quickset Blade Chuck I don't think this model is still available.

The lever would fit in the slots in pic #5 & keep the barrel piece parallel, the wire clip holds the jaws together.

The Delta 40-450 saw have these types of blade holders, you can find them on craigslist or facebook market for under 50.00, they are a good saw, I have 2 plus 2 for parts.

My brother said first thing to try is plug it in and push on all the soldered connections with a pencil eraser checking for bad solder joints. Being careful of course.

OK, I found this,

Although I don't think it is exactly what Delta used, I think it will help determine the location of the problem. This is a treadmill speed controller diagram.

From your picture, I think the large, round black cable, going to the motor, is the same ae the blue wires shown in the diagram above. Because the motor runs, but at full speed, I believe the thermal overload circuit inside the motor is functioning, as is the fuse and "safety switch" (On/Off switch).

I cannot be 100% certain but I think the speed control is a "Pulse Width Modulation" -PWC- type controller. That means the controller turns the voltage off and on- to the motor- very quickly- pulses. The longer the positive pulses the faster the motor runs.

When reading about this saw, users mentioned the saw has a brief delay when starting up due to a feedback ckt with the motor speed control. I think that feed back is through one of the wires in the little brown connector 3 wire connector. Some owners indicated a failure in the feedback ckt can cause the motor to run wide open,

The sensor for the speed feedback is located in the saw motor. Typically there are several speed SENSORS used for DC.

A Hall Effect Transistor

This type of RPM detector relies on a magnet mounted on a rotating device, passing close to the transistor to sense the rotation.

U-shaped slot photoelectric sensor

This type uses a rotating slotted wheel to pass through the "U" shaped opening to make/brake an IR light to sense rotation

LED RPM Detector

This type uses an LED light and a reflector on a rotating shaft/wheel to detect motion. (Reference image only)

Because both circuit board had the same results, I would remove the back (rite in your pix) end of the motor and inspect the ckt inside. Look/smell for anything burned/discolored. Maybe something loose/missing on a shaft.

Hope this helps.

Let me know what you find!

1 minute ago, Lost Oki said:

WHOA, Thank You, starting to make sense. THANK YOU LEW.

Keep me updated on the progress. Really interested on what's happening in side the ckts.

49 minutes ago, Lost Oki said:

I cannot say enough about the help I got from WestArk.

A positive review like this is one way. I agree with @lew that finding places like this is getting harder so really nice when you find one.

Sorry to hear the news about the circuit boards Don. I don't suppose the seller of the new one would take it back &/ or reimburse you? Great to hear the motor is OK though and you've found a work around. Can't beat the service from WestArk. As already mentioned by others, those kind of businesses are far and few anymore.

2 hours ago, Lost Oki said:

A little off topic but d o any of you have a shop smith and in need of a Beale 3 on lathe mandrel (hold 3 buffing wheels)

There are several SS users here. You might try posting the mandrell for sale in our Shop Smith Classified/ Trade Forum HERE and/ or in our Classified Swap and Sale Forum.

https://thepatriotwoodworker.com/forums/forum/37-the-classified-swap-and-sale/

After looking at the last image (lower rite) it reminded me of the adapter that came with my very old Taiwanese scroll saw. My saw was made to use pinned blades but also came with an adapter for pin less blades. Maybe it will give you an idea for something you can make.

The adapter-

7 hours ago, Lost Oki said:

Update on the Delta. As stated earlier I have a work around for the bad printed circuit and it works. Upper blade chuck is together and seems to work. Lower blade chuck is incomplete but I may have a work around and need some input.

See posted pics. 1 is alignment of top and bottom chuck (ignore the oven in background). 2 is lower chuck incomplete. 3 is possible modification. My concern is if I remove the lower chuck - blade seems to be slightly to rear of screw holding assembly to lower arm. If I use pic 3 mod with a home built connecting block (measured and will work) is the blade going to be out of alignment with top chuck? OR am I overthinking this. Connecting block would be steel although I do have brass

---

Picture #2 is of the lower blade clamp, correct? If it is, it appears that the plate with the "hooks", on the right side is installed backwards; the "hooks should face away from the other side, and you should be able to clamp a blade in the lowers holder by tightening the nut with a nut driver.

Tightening the blade: loosen nut until blade can be slipped into the space between the two plates (in the front of the assembly), rest the blade on the lower housing, push the blade back as far as possible, carefully tighten the nut while holding everything in place. Thread blade through pilot hole and use the upper clamp, then apply tension.