what blade to cut steel with a DW718

[bc30se]

I don't care about the slides on the cheap chinojunk, I can blow it away with a gun each time I work, I need easy angles only... I will have to check myself.

 

[ned]

Agreed. easy, repeatable angles would be great.

 

[ned]

some shots of the belt on the 718, the upper roller is bigger than the the lower one coming off the motor, probably I can swap around these to get slightly higher RPMs.
Not sure are the drive rollers the same as serpentine belts on cars.

Below is the washer that sits between the spigot (?) and the 30mm bore of the blade. Interior diameter is 16mm. There are 12 inch abrasive blades available with a 20 and also 22mm bores, might order this washer and get someone to turn it down to 20mm on a lathe. Then I'll chance the dewalt with an abrasive blade. It wont be expensive to try it out, so I'll go ahead and do it.
I think an abrasive blade will be easier on the motor and belt, if I can get the RPM's close. The 12 inch abrasive disc i have is looking for 5800 rpm.

 

[ned]

Ah cool. Its rated at 4krpm so if I reverse the rollers I should get maybe 4200, at a totally random wild guess )

 

[ned]

okay will do that later, nice one )

 

[bc30se]

nice, looking at your progress..

 

[ned]

Cheers BC30se )

I found an adapter ring for 6 euros posted, which is good.

http://www.ebay.co.uk/itm/171747587131

Another seller wanted 20 euros posted, for a frigging washer.

 

[ned]

PDG hi, the bigger roller is 30mm and the smaller is 25mm


looking at this photo, one thing that worries me is the amount of sawdust that gets into the motor housing. I wonder how metal cutoff saws deal with steel dust in the motor?

 

[DanielW]

Cheers BC30se )

I found an adapter ring for 6 euros posted, which is good.

http://www.ebay.co.uk/itm/171747587131

Another seller wanted 20 euros posted, for a frigging washer.

Beauty of having a lathe,to make these stepdown rings or step up?

Most good blades come with a set of three sized rings.

 

[bc30se]

Don't worry about dust, just leave the belt cover open while you work and blow air from time to time and you will be fine

 

[ned]

cheers bc30se.


pdg, I took those measurements with a vernier calipers so they should to be accurate.
Regarding the rpms;

2736 - 5760 = 3024

5000 (for abrasive blade) - 2736 = 2264

2264 as a percentage of 3024 = 74.9%

so I need to have the dial at 3/4 to achieve 5000rpm. I'm horrible at math but i think that's right.

I'd be interested to know the rpm range if I had two 25mm (or two 30mm) pulleys, rather than one bigger than the other. Might eliminate the possibility of running the motor too fast for the blade.

 

[ned]

excellent stuff man, really appreciate it. Will report back when I get the thing moving so, it will be next week before the blade adapter ring arrives, so I'll try it out then.


regards.

 

[ned]

so i took off the pulleys and had a look at them, applied heat with a mapp torch to get them off, managed to not melt any plastic.

Okay I melted a small bit of plastic..

the two shafts area different diameter, the one by the blade is 12mm with one key, and the one attached to the motor is 14mm with 2 keys.

So I aint getting anymore speed out of it, however this kinda makes my life simpler - once the blade adapter arrives I'm done.
I alligned the blade as best i could (difficult) and cut a small piece of box, it went through it no probs.

It was vibrating a bit so I was a nervous, but it did go through it before i decided f*** that for a game of soldiers.

A lot of sparks were kicked up, so I'm going to get some sheet metal and create a shield behind the blade to direct the sparks and metal dust away from the body of the saw, maybe i can make some kind of a funnel to direct it into a small bin of some description.

Anyways, its worked well and I'm very happy. I'll take some video once I get the blade adapter. First dewalt tool I've owned and after taking it apart I have to say its nicely made.

 

[bc30se]

ehhh... I have been sweeping my thoughts of having one for so long because I was afraid it is not going to work... what a fool I am...

 

[DanielW]

http://www.toolstation.com/shop/Pow...scs/sd1750/Metal+Chop+Saw+Cutting+Disc/p63437

 

[ned]

bc30se fair play to you man, unless you had chimed in when you did, I wouldnt have thought of it. Glad I started this thread now, learned a lot, great stuff.

 

[ned]

So I cut some steel with it, truth be told I'm pretty sick right now so it was a half hearted attempt, but i did test it out.
The adapter arrived yesterday from that ebay auction. The washer is about 1mm thick, and the consaw disc is 3mm thick, so yah, the size of the washer wouldnt fill you with confidence, however, the diameters are perfect and it does work.

Regarding actually cutting with it, I guess it will take some getting used to. I think i drove down too hard on the blade, I'll explain why;

A guy i was living with advised me that with an abrasive cutoff saw, you are better off to jam/push the blade into the metal in repeated motions, something about the disc glazing over if you try to do it in a smooth motion. So I've been doing that.

I tried that with this saw, however, i don't think the motor is as powerful as on my makita cutoff saw (I'll check the specs on them both later).
Anyway the blade did slow down, so i had ease off and let it spin up to full speed again, then try again, a bit gentler. So yah it will take a little getting used to.

Also I have no clamps for this saw, so the metal vibrated a little, its not a perfect cut. - It's not a terrible cut either though.

I'd like to build a horizontal vice into the left hand side of the saw as you look at it, like a traditional metal vice.
I dont care about wrecking the aesthetics of the saw, i just want it to function.

 

[roofman]

You might have to make a reducing spacer for the spindle...the industry for some reason makes it very hard to put steel cutting blades into wood cutting machines due to spindle bore size differences... I may be wrong with these new multi cut style blades..

EDIT....LOL too late,looking at the post above

 

[brianblock]

Would the clamp I posted earlier not work?
Works fine on ours holding down Ali, and not too prices either

 

[bc30se]

I think you need to eat the material as slowly as possible and of course clamps must rather be there...