Rewiring DeWalt Saw for 120v

[beginner54]

Just picked up an old DeWalt Radial Arm Saw from Craigslist in nearly mint condition for $100. Always wanted one and am thrilled to have the tool and the space. It's a model 1511 circa 1966 and is currently wired for 240v but I only have 120v outlets in the space. The saw is designed to run at either voltage and the rewiring diagram printed on saw motor seems very straight-forward so I'm pretty confident with this piece. But I'm wondering:

1. Is there any inherent disadvantage to running the saw on 120 vs 240? Someone said it will have less power. Someone else said the motor won't last as long. I'm a recreational user and won't be using it that much but was curious about the pros and cons. (I could theoretically run a new 240 circuit to the area but would like to avoid it if possible.)

2. Once I rewire the motor for 120, can I use an adapter I found on Amazon to change the old 240 plug to fit my 120 outlets... or do I need to replace plug and/or cord completely?

Thanks for any advice!

Rick

 

[rjn2649]

Hi Rick,
I love my radial arm saw. AND I got all my fingers.
I would go over here for DeWalt saw info :
http://forums.delphiforums.com/woodbutcher

I recently re-wired my table saw for 220, It seems to feel like it has a bit more power, but that could be subjective.
If it wasn't easy for me to get 220 there I wouldn't have done it.
Myself, I'm not a big fan of adapters for plugs, right plug for the right voltage/amps

Rick

 

[sberry]

It will run basically the same. As long as it isn't tripping the breaker you are good to go. My table saw can be wired either way, I keep it 120. Change the plug.

 

[beginner54]

Thanks Rick! I joined the delphiforums group last week and you're right, it's a great resource... kinda like GJ!

 

[walta]

Whether it will work or not will mostly depend on the wiring in your walls.
When you decrease the voltage you increase the current.
So when you half the voltage you double the current.

If the wires going from your panel to your shop
1 Are 14 gage with a 15 amp breaker the motor is unlikely to start most of the time.
2 Are over 100 feet long 12 gage with a 20 amp breaker the motor is unlikely to start
most of the time.
3 Are less than 50 feet long 12 gage with a 20 amp breaker the motor is likely to start
just fine.

If the motor is slow to start and light on the same circuit dim the saw needs more current than that circuit can provide and you are risking damage to the motors windings using that circuit.

You have a great tool. If you are sure you are smart enough not to cut your fingers off and have the nerves to make a rip cut on it. You and that tool can do almost anything. If you plan on staying in this shop for very long do yourself a favor and install the 240 volt circuit.

Please post a link to the adapter you found. My guess is it does not do what you want. Should it work would be a dangerous thing in the hands of someone that does not understand its intended purpose. Also the adapter most likely costs more than the correct plug.


Walta

 

[beginner54]

Great information, Walta, thanks. The outlet is on a 12-2 20 amp circuit about 4 feet from the panel, so it sounds like it'll work fine as long as I don't run anything else on the same circuit when the saw is running. Should be no problem as I have four 20-amp runs in the shop. My next post will include link to Amazon adapter (GJ won't let me include links until I have 5 or more posts... I'm at 4!)

 

[beginner54]

Here's a link to the Amazon adapter: <<https://www.amazon.com/dp/B078SNBT4L/ref=twister_B078SLN21D?_encoding=UTF8&psc=1>> I agree it'd be cheaper to put a new plug on, but if there's no safety issue using it I'm inclined to go with the adapter to keep all original parts and have the option to easily switch back to 240 if I end up installing new circuit as you suggest.

I appreciate your comments about being smart enough not to cut off my fingers--I hope I am! I bought it mainly for cross cutting and will stick with that for the foreseeable future. Thanks again.

 

[captaindiode]

One danger with the radial arm saw is that it will try to "climb" the board as you cross cut. Always have a firm grip on the saw and watch your left thumb. Also, there are baldes specifically made for the radial arm saw to reduce the tendency for it to run towards you. As for the adapter, just change the cord end. If the saw is wired for 120, and plugged into 240 by accident bad things can happen. If you change the end, this can't happen.

Here is an example blade, but yours may be larger.

https://www.amazon.com/dp/B003XREDZK/?tag=atomicindus08-20

 

[mm08822]

Great information, Walta, thanks. The outlet is on a 12-2 20 amp circuit about 4 feet from the panel, so it sounds like it'll work fine as long as I don't run anything else on the same circuit when the saw is running. Should be no problem as I have four 20-amp runs in the shop. My next post will include link to Amazon adapter (GJ won't let me include links until I have 5 or more posts... I'm at 4!)

Being only 4' to the panel, I would add a 240v, 20a recept instead.

 

[johnnyradiant]

Being only 4' to the panel, I would add a 240v, 20a recept instead.

me too

I have an old 10" DeWalt that has a 120/240 switch on it. It was my dad's site saw. I have only ever used it or watch my dad use it in the 240 mode. My old 12" DeWalt is only 240v. They are lovely saws and I won't part with either of them mainly sentimental reasons though. I've ripped enough on them to know there is a reason I have three table saws. A good radial arm saw blade (that is kept sharp) makes a huge difference.

 

[u3b3rg33k]

Whether it will work or not will mostly depend on the wiring in your walls.
When you decrease the voltage you increase the current.
So when you half the voltage you double the current.

If the wires going from your panel to your shop
1 Are 14 gage with a 15 amp breaker the motor is unlikely to start most of the time.
2 Are over 100 feet long 12 gage with a 20 amp breaker the motor is unlikely to start
most of the time.
3 Are less than 50 feet long 12 gage with a 20 amp breaker the motor is likely to start
just fine.

If the motor is slow to start and light on the same circuit dim the saw needs more current than that circuit can provide and you are risking damage to the motors windings using that circuit.

You have a great tool. If you are sure you are smart enough not to cut your fingers off and have the nerves to make a rip cut on it. You and that tool can do almost anything. If you plan on staying in this shop for very long do yourself a favor and install the 240 volt circuit.

Please post a link to the adapter you found. My guess is it does not do what you want. Should it work would be a dangerous thing in the hands of someone that does not understand its intended purpose. Also the adapter most likely costs more than the correct plug.


Walta

I disagree with you. why would an unloaded motor refuse to start? maybe with 100' of 16ga wire, but 100' of 12ga should start it just fine.
the only time i've ever seen this be a problem was my cheap friend trying to run a sump pump on a $100 generator with a 100' 16ga cord. so many problems idk where to start...

My snow blower and lawn mower both run on a 100' 12ga cord, and the snowblower moves thick stuff with gusto.

either way, the windings in that saw only see 120V. if wired for 120V they're in parallel, and if wired for 240V they're in series. all that matters is you can provide enough current to the point where the wires tie in.

mind you i see no reason NOT to have a 240V outlet (or 5) in the garage.

 

[sberry]

In this case if there are free spaces it would be about as easy to add a circuit. The main reason for 120 is to make it easy to move. As for wearing it out, making it last, having more power it wont make any difference to you. The duty cycle and load are so low it's irrelevant.
You are so close to the panel any looses do not matter, only issue is breaker trips. Sometimes being so close they do with large motors, deliver so much current so fast.

 

[wyliesdiesels]

Motors run hotter when they use more current. So the saw may run a little hotter when on 120v because when voltage is halved, current is doubled.

Since panel is so close, i would put in a 240v outlet.

 

[James-W]

My table saw can run either way, but I am running it on 240. It is probably just my imagination, but for some reason it just seems to run better on the higher voltage. It is a 3 hp motor if that makes any difference.

 

[sberry]

It would need to be pretty extreme to make a noticeable difference, most of it is theoretical.

 

[beginner54]

Thanks everybody! Just to make sure the saw ran the way it did before I bought it, I reconfigured the motor for 120, added a new 120 plug (no adapter) and fired it up. It worked beautifully! I think I'll leave it this way for the time being--adding another 240 circuit would be simple enough but the machine is working 100% for my needs at this point and I can move on to other projects... Captaindiode, thanks for the sawblade link, I was wondering where to find a negative kerf blade.

 

[walta]

Once you understand what you are looking for it is not hard to tell what blade you want with just a look.

Worth a read saw blade 101
http://www.rockler.com/how-to/blades-101

Walta