Worm Drive Radial Arm Saw

[jgrickett]

Question for the group: Several years back I saw, on FB marketplace, a radial arm saw with a worm drive motor. If I recall correctly, it was a Sears Craftsman. I needed another saw like I needed a third nostril, so I didn't buy it, but it's intrigued me ever since. It seems as if a worm drive would solve one of the biggest problems with the small-shop RAS: lack of power. Even with the bottom of the motor flattened the way DeWalt and Delta made them, you run into clearance problems with a sidewinder motor.
Has anyone here got one of these, or used one enough to get an idea of how well that worked?

 

[Roberts210]

I've personally never heard of a worm-drive RAS, but somebody probably made them at some point.

For 30 years I've owned Comet Cub radial arm saws. At one time I owned 6, but I'm down to 2 now and a spare motor. Comet Industries made those big, hulking 14" and 16" RAS you used to see in lumber yards, especially up and down the West Coast. In the 1950s Comet tried to crack the home owner market with the Comet Cub. These husky RAS run an 8.5" blade, but the blade is offset, so they cut as deeply as a 10" RAS. Blade speed is 4500 RPM while the motor turns 6700 RPM. They run a flat belt in the offset design. Once set, the adjustments are rock solid and will not creep. Cubs were only sold in lumber yards, and Comet couldn't compete with Sears' marketing even tho the Cub was and is a far superior RAS.

 

[RTM]

They were out there, but the google results are all in Snippet view. A bit of searching in alternate sources like archive.org might find the same literature fully available.

"worm drive" AROUND(4) "radial arm saw" - Google Search

 

[jgrickett]

I've personally never heard of a worm-drive RAS, but somebody probably made them at some point.

For 30 years I've owned Comet Cub radial arm saws. At one time I owned 6, but I'm down to 2 now and a spare motor. Comet Industries made those big, hulking 14" and 16" RAS you used to see in lumber yards, especially up and down the West Coast. In the 1950s Comet tried to crack the home owner market with the Comet Cub. These husky RAS run an 8.5" blade, but the blade is offset, so they cut as deeply as a 10" RAS. Blade speed is 4500 RPM while the motor turns 6700 RPM. They run a flat belt in the offset design. Once set, the adjustments are rock solid and will not creep. Cubs were only sold in lumber yards, and Comet couldn't compete with Sears' marketing even tho the Cub was and is a far superior RAS.

I've personally never heard of a worm-drive RAS, but somebody probably made them at some point.

For 30 years I've owned Comet Cub radial arm saws. At one time I owned 6, but I'm down to 2 now and a spare motor. Comet Industries made those big, hulking 14" and 16" RAS you used to see in lumber yards, especially up and down the West Coast. In the 1950s Comet tried to crack the home owner market with the Comet Cub. These husky RAS run an 8.5" blade, but the blade is offset, so they cut as deeply as a 10" RAS. Blade speed is 4500 RPM while the motor turns 6700 RPM. They run a flat belt in the offset design. Once set, the adjustments are rock solid and will not creep. Cubs were only sold in lumber yards, and Comet couldn't compete with Sears' marketing even tho the Cub was and is a far superior RAS.

I don't believe I've ever seen a Comet. I was going to ask if they use a belt or gears to offset the blade from the motor shaft, but I see you answered that. The only disadvantage to the design, so far as I can see, is that it can't be mounted close to a wall. I especially like the large handwheel for the vertical adjustment. The crank on my Rockwell is a finger-pinching monster, and the one on my DeWalt isn't much better.
The Craftsman RAS was sort of the lowest common denominator of the type, at least in the Emerson years. Ryobi might have taken over in that category, had theirs lasted longer. I gather the blade guard assembly could fail without warning and there was a recall. I had a 10" Craftsman for years, and got a lot of use out of it, but needed the room and gave it to my brother-in-law, who still uses it. Emerson sold the same machine under the Rigid brand, and while they weren't top line, they did offer good customer support. Even the DeWalts went downhill over the years, though never quite as far. They kept reducing the weight and rigidity of the subframe and making the table out of ever-cheaper material, making the machines difficult to keep in tune.
I'm currently working on restoring a 10" Rockwell Delta 10" turret RAS, and finding mysteries everywhere. The motor appears original to the machine, which seems to date from the 1960s, but it's clearly labeled "Black & Decker." Some former owner removed and bypassed the thermal overload switch in the motor housing, and the motor windings show definite signs of overheating, though it still runs. The housing also says it has a built-in brake, but I can't find any sign of that. If I decide to pull it all the way down and replace the bearings, perhaps I'll find it, or at least where it was.
Lots of work ahead. The former owner apparently discarded the leveling hardware for the table and just bolted it to the stamped steel haseplate, so I'll need to find or make replacements for that. I'll also replace the original switch with a magnetic switch with a thermal overload built in. With that and a new table, I'll have a working saw.

 

[Roberts210]

Yes, the Comet uses a flat belt, 10X1 I believe. In 30 years of using them I've never had to change a belt because it failed. New belts are still availble through Jason.

Good luck with your Rockwell Delta turret RAS. They are great saws.

In the 1970's I took the pass seat out of my Camaro and drove down to Sears and came home with a brand spankin' new Craftsman RAS in a box. I LOVED THAT SAW. I did everthing with it. The downsides were that it came with an aggressive blade that self-fed to an alarming degree, so I learned to stiff-arm the handle wherever I cross cut with it. That, and the adjustments would creep after a bit.

 

[micromind]

I don't believe I've ever seen a Comet. I was going to ask if they use a belt or gears to offset the blade from the motor shaft, but I see you answered that. The only disadvantage to the design, so far as I can see, is that it can't be mounted close to a wall. I especially like the large handwheel for the vertical adjustment. The crank on my Rockwell is a finger-pinching monster, and the one on my DeWalt isn't much better.
The Craftsman RAS was sort of the lowest common denominator of the type, at least in the Emerson years. Ryobi might have taken over in that category, had theirs lasted longer. I gather the blade guard assembly could fail without warning and there was a recall. I had a 10" Craftsman for years, and got a lot of use out of it, but needed the room and gave it to my brother-in-law, who still uses it. Emerson sold the same machine under the Rigid brand, and while they weren't top line, they did offer good customer support. Even the DeWalts went downhill over the years, though never quite as far. They kept reducing the weight and rigidity of the subframe and making the table out of ever-cheaper material, making the machines difficult to keep in tune.
I'm currently working on restoring a 10" Rockwell Delta 10" turret RAS, and finding mysteries everywhere. The motor appears original to the machine, which seems to date from the 1960s, but it's clearly labeled "Black & Decker." Some former owner removed and bypassed the thermal overload switch in the motor housing, and the motor windings show definite signs of overheating, though it still runs. The housing also says it has a built-in brake, but I can't find any sign of that. If I decide to pull it all the way down and replace the bearings, perhaps I'll find it, or at least where it was.
Lots of work ahead. The former owner apparently discarded the leveling hardware for the table and just bolted it to the stamped steel haseplate, so I'll need to find or make replacements for that. I'll also replace the original switch with a magnetic switch with a thermal overload built in. With that and a new table, I'll have a working saw.

That's the same motor used on the B&D/DeWalt 12"saws.

 

[jgrickett]

That's the same motor used on the B&D/DeWalt 12"saws.

Thanks! Good to know. Now I just have to figure out how it got there and where to find a replacement thermal overload. I suppose someone could have scavenged a B&D motor off another saw, but the carriage is definitely a Delta and I'd be shocked to find the trunnions would be close enough to allow the swap. Besides that, most 12" saws seem to have a 1" arbor, and this is a 3/4".

 

[micromind]

Thanks! Good to know. Now I just have to figure out how it got there and where to find a replacement thermal overload. I suppose someone could have scavenged a B&D motor off another saw, but the carriage is definitely a Delta and I'd be shocked to find the trunnions would be close enough to allow the swap. Besides that, most 12" saws seem to have a 1" arbor, and this is a 3/4".

It might be 3/4 but more likely 5/8. Also, left-hand threads.

Sort of a side note, to loosen an arbor nut, hold the shaft and turn the nut in the direction the blade goes.

It's possible that Delta bought DeWalt motors and designed their trunnion around them.

The brake involves using the start relay to short out the motor thus slowing it down then at low speed, a mechanical brake located at the fan end brings it to a stop.

 

[jgrickett]

It might be 3/4 but more likely 5/8. Also, left-hand threads.

Sort of a side note, to loosen an arbor nut, hold the shaft and turn the nut in the direction the blade goes.

It's possible that Delta bought DeWalt motors and designed their trunnion around them.

The brake involves using the start relay to short out the motor thus slowing it down then at low speed, a mechanical brake located at the fan end brings it to a stop.

Yes, 5/8. No clue what I was thinking earlier.
I'm familiar with the electronic brake. My DeWalt has, or rather had, one like that. Some oaf dropped something very heavy on the box that held the circuitry, smashing it and the little glass-enclosed relay inside, before I bought it, and the last owner had just bypassed it all and started and stopped it by plugging and unplugging the saw. I've also found a manual on the Delta mechanical brake posted on the Vintage Machinery website, but there's no sign of it in the saw motor.
When I first started messing with the DeWalt, about six years ago, I was told to forget about rebuilding that brake, as those relays were totally unobtainable. Someone had a diagram posted on a DeWalt forum of a replacement he'd put together using modern components, but he was having trouble with it slowing the blade too fast, causing the arbor nut to come loose. That sounded like a cure worse than the disease, so I've left it alone and just let the blade spin down on its own. I recently looked into it again, and someone has posted a YouTube video showing where to get all the parts, including the relay. It turns out they've been out there all along at a place that sells replacement parts for vintage tube amplifiers and such. Apparently electric guitar players are too fond of their fingers to risk them around circular saws, so there's not much overlap of interests. Now I have to find where I put that box.
I think you're correct about the source of the motor. Unlike DeWalt, Delta seems to have out-sourced motors and other bits and pieces back in those days. For that matter, they out-sourced the entire saw originally. That turret design was developed by a company called Red Star Products, back in 1936, and Rockwell bought them out in 1948 and began marketing the saws under the Delta name. If anyone's interested, someone in Pahrump, Nevada, has one of the Red Star saws advertised on FaceBook Marketplace for the princely sum of $47.

 

[cnc-me]

I don't believe I've ever seen a Comet. I was going to ask if they use a belt or gears to offset the blade from the motor shaft, but I see you answered that. The only disadvantage to the design, so far as I can see, is that it can't be mounted close to a wall. I especially like the large handwheel for the vertical adjustment. The crank on my Rockwell is a finger-pinching monster, and the one on my DeWalt isn't much better.
The Craftsman RAS was sort of the lowest common denominator of the type, at least in the Emerson years. Ryobi might have taken over in that category, had theirs lasted longer. I gather the blade guard assembly could fail without warning and there was a recall. I had a 10" Craftsman for years, and got a lot of use out of it, but needed the room and gave it to my brother-in-law, who still uses it. Emerson sold the same machine under the Rigid brand, and while they weren't top line, they did offer good customer support. Even the DeWalts went downhill over the years, though never quite as far. They kept reducing the weight and rigidity of the subframe and making the table out of ever-cheaper material, making the machines difficult to keep in tune.
I'm currently working on restoring a 10" Rockwell Delta 10" turret RAS, and finding mysteries everywhere. The motor appears original to the machine, which seems to date from the 1960s, but it's clearly labeled "Black & Decker." Some former owner removed and bypassed the thermal overload switch in the motor housing, and the motor windings show definite signs of overheating, though it still runs. The housing also says it has a built-in brake, but I can't find any sign of that. If I decide to pull it all the way down and replace the bearings, perhaps I'll find it, or at least where it was.
Lots of work ahead. The former owner apparently discarded the leveling hardware for the table and just bolted it to the stamped steel haseplate, so I'll need to find or make replacements for that. I'll also replace the original switch with a magnetic switch with a thermal overload built in. With that and a new table, I'll have a working saw.

That motor is the same as used on Dewalt RAS. Maybe it predates B&D's purchase of Dewalt
The brake is built in under the top cover, I think it used a potential relay or something to engage the start windings.
I can get some pictures if you wish.
Update: Now I'm thinking that it's an actual Dewalt motor with B&D's name slapped on the side.

 

[jgrickett]

Thanks! I've looked inside the cover, and there's the starting capacitor plus a large open relay that probably serves the same purpose as the smaller glass-enclosed one that DeWalt used in their dynamic brake system. If you do have photos of one of those B&D motors, though, I'd appreciate anything that shows the thermal cutout, doubly so if there's a visible part number. Some former owner removed and bypassed the one in mine, and then covered the holes with duct tape. I'd like to put a proper one back in, even if I get a magnetic switch with a built-in thermal overload. I've no idea whether there's anyone left who can rewind that motor, and if there is, I don't want to know what they charge for that. Cheaper, I'm sure, to find a replacement motor somewhere.