Modding a Rigid Bandsaw to cut steel [Archive]

JohnUlaszek

01-15-2005, 07:05 PM

Thought you guys might like this.
Paul Ruggles modded a Home Depot Bandsaw to cut at 80-120 and 170-250 surface feet per minute, perfect for cutting sheet metal and plate.
Hacked Band Saw (http://www.x1nova.com/Tools.html)

https://static1.pt-content.com/images/noimg.gif

parsonsj

01-15-2005, 07:51 PM

Damn. That thing just went to the top of my "gotta have" list!

I've been using a poor man's bandsaw recently: I clamp my jigsaw in a vise upside down. That works (sort of ... I still have ten fingers), but I'm always wanting a real vertical bandsaw. The $1000+ price tag has always put me off.

Is Paul up for making more?

jp

JohnUlaszek

01-16-2005, 08:05 AM

John,
I talked to Paul about building more but he wants to do some durability testing before he takes that on. Send me your address so we can get one down to you to test.

John

astroracer

01-16-2005, 08:48 AM

Hey John!
Perfect timing on this one bud! I just bought a 12" wood band saw off eBay for less then 100 bucks including shipping. This saw has a variable speed but it is still too fast. This was my plan to convert it over to cut steel... Any chance on getting specifics for us other D.I.Y. guys? Pulley sizes would be excellant.
Mark

JohnUlaszek

01-16-2005, 09:52 AM

Mark,
Paul came up with a design and mechanism that works for the Rigid and maybe the Habor Freight but your drive mechanism, motor speed, and room for packaging will drive your design.
The pulley diameters we used probably won't help you as we are starting with a different motor and pulleys and the wheels on the saw itself are different diameter.
I believe the machinists handbook has some pulley calculations in it. Your first task will be to see how many SFPM you machine is right now.
Sorry I can't be more specific, but its a bit of an engineering problem with unknown variables. Initially we had hoped to just swap pulleys, but that would have actually sped the thing up. It's not trivial to slow woodcutting saws down to the usable speed.

KWIKND

01-16-2005, 01:59 PM

What about a freq drive(variable frequency drive)? Slow the motor down while maintaining full torque. We use them on overhead cranes 0 to 150% speed :naughty: - 250 ton hoists.
Dan

JohnUlaszek

01-16-2005, 02:53 PM

Dan,
We thought about that, but we felt a pulley system would be the cheapest route and would allow the motor to operate at its designed RPM. The motor on the saw is a single phase 110v motor and is only rated at 1/2hp. Freq drives are not cheap but If you think you can get one working let us know how it turns out.

John

KendallF

01-16-2005, 06:22 PM

JohnUlaszek

01-16-2005, 06:29 PM

The wood cutting blade is useless for cutting steel.
We switched over to a Starret 14-18 skip tooth blade. At 80 SFPM it cuts sheet metal like butter and its quiet. THe 93.5" blade is a standard size for cutting metal.

astroracer

01-17-2005, 09:57 AM

Thanks John,
I figured I would have to recalculate blade speeds and pulley sizes for my saw. I guess I was more curious as to what bearing blocks or jack shafts you used. I probably should have asked that rather then pulley sizes...
Thanks again.
Mark

JohnUlaszek

01-17-2005, 06:41 PM

Mark,
We used standard .750" keyed shaft available from McMaster Carr. The bearings are sealed cartridge bearings in a machined block. Calculating pulley ratios and then designing the thing to have proper belt tension is critical or the blade will stall on heavier cuts.
The pictures don't show how it attaches but it has a frame that ties the motor and saw together at the base and makes it much more rigid than the factory setup. Paul is thinking about selling these if there is enough interest but only after he has had time to work out all the bugs and do some durability testing. John Parsons has agreed to test one out and see if he can break it.

parsonsj

01-17-2005, 07:17 PM

Yeah ... somehow I talked Paul into sending me his prototype. I'll give it a solid go, and report back here in a week or two. I have some sheetmetal and tube work (both steel and aluminum) to do, so I will exercise the saw a bit.

jp

astroracer

01-18-2005, 03:08 AM

Sounds good John, and thanks for the info. I was scoping out parts in both McMaster-Carr's and Grainger's catalogs yesterday. I also went out and dinked around with the 12" variable speed saw I bought and decided it's not worth messing with. I will leave it alone and use it for cutting wood only. It's got a small motor on it and the variable speed leaves it with no torque at metal cutting speeds... No great loss for 70 bucks. I will be picking up one of the bigger 14" saws shortly. Do you have any suggestions or things I should be looking for different then the Rigid saw? I will be checking out Harbor Freights offerings and Sears has one that is similar so I should be able to come up something that will work.
Mark

JohnUlaszek

01-18-2005, 04:33 AM

Mark,
The harbor freight model can be caught on sale for $229.00 and is worth considering on price, but of the higher quality models the Rigid seemed the best bang for the buck.

John

parsonsj

01-23-2005, 09:33 AM

Well, after convincing the concerned sales staff at my local Home Depot that they actually do have such a saw and that their job is to find it and sell it to me, I drug one of the 200 lb beasts home today.

Paul's conversion kits will be here this week, so I'll have some reaction about this inexpensive metal bandsaw experiment next weekend.

jp

Jim Nilsen

01-23-2005, 04:04 PM

Hey John, I did the same thing to my Jet wood bandsaw and it works great.Jet actually had a kit to adapt over .

If you can ,you need to make it so you have a speed right in the middle or a little faster for cutting aluminum. I use a larger pulley on the drive wheel to do it.

Wood blades work great for cutting aluminum when set at the right speed. A wire clean off wheel helps a lot too for blade life. My saw right now will cut through half inch aluminum 6061 t6 like butter. The variable tooth blades under 12T work the best.

I had just seen a 2 in 1 Delta in a local Farm & Fleet and in there catalog that had the lowered motor and jackshaft setup for being able to go slower. It was only $300 and the wood bandsaw only was $ 400 go figure ? If I didn't already have one I would have taken it home with me !

Goodluck , Jim Nilsen

parsonsj

01-23-2005, 08:35 PM

Hi Jim,

Been a while since we've heard from you. Welcome back!

I checked out the Jet speed conversion kit and it seems a bit fast for steel: only 725 sfpm as the slowest. That's too fast for steel, but may be ok for aluminum. The Delta 2n1 is EXPENSIVE: $1600! At least new it is, anyway.

This Rigid deal is $350 for the saw, and $200 or so for the kit. Paul is verifying the actual speeds with a tachometer (must be something different than what I was thinking of :) ), but thinks he got somewhere around 40 sfpm up to about 120 or so (it's adjustable).

Anyway, I'll post when I have some actual run time on the saw.

jp

astroracer

01-25-2005, 04:50 AM

I just bought an older, taiwanese style 14" saw on eBay for $132.50. It is supposed to be a dual type saw. Wood and metal. Used very little and kept in storage, out of the weather. I will be picking it up Saturday.
Obviously I can't give you any info until I get it in my shop and check it out but this was a hellofa deal and I'll be able to throw some time and money at it too get it up to speed.
I will post some pics next week.
Mark

JohnUlaszek

01-25-2005, 06:29 AM

The thing to keep in mind is that you need to be down around 80 SFPM minute to cut sheet metal properly. Most of the dual purpose machines have a low speed that is way too fast. They claim they are good for metal but are typically around 700 SFPM on the low speed which will cut aluminum sheet but not well.

Let us know how your machine works and if you can mod it to run slower.
There is a real need for a hobbiests band saw for cutting steel and as of yet Pauls solution is the only one I would consider affordable if he decides to start making them.

John

BADVELLE

01-27-2005, 08:55 AM

Great idea! I have seen a few other people try this..and I was just in Harbor Freight today looking at the metal bandsaw they have for $159 and thinking that it'd work, but 4 1/2" throat depth isn't going to allow cutting bigger stuff.

I have a question: how does the wood blade do for cutting steel, and is the blade length a common size where you can swap for a blade with appropriate TPI count for steel?

I bought that vertical/horizontal from Harbor Freight thinking it would be great for my shop use. I have adjusted and re-adjusted and it still throws the blade almost everytime. I am only cutting 1/16" plate and taking my time at that. I am just done fooling with it, going back today. I just believe I actually paid for what I got, a piece of crap!! I always say, you can't polish a terd and in this case I seem to be right!

sanddan

01-27-2005, 10:51 AM

I had the same problem with my Jet 4x6 bandsaw. The link below outlines how to set up this type of saw. Mine now works better than it ever has. Hope this helps.
Dan

http://www.mini-lathe.com/Bandsaw/Bandsaw.htm#bandsaw (http://)

BADVELLE

01-27-2005, 12:12 PM

astroracer

01-27-2005, 02:54 PM

I bought that vertical/horizontal from Harbor Freight thinking it would be great for my shop use. I have adjusted and re-adjusted and it still throws the blade almost everytime. I am only cutting 1/16" plate and taking my time at that. I am just done fooling with it, going back today. I just believe I actually paid for what I got, a piece of crap!! I always say, you can't polish a terd and in this case I seem to be right!

See if this link works...
http://www.mini-lathe.com/Bandsaw/Bandsaw.htm#Table
Craig,
Are you using the original blade? I'll garauntee that is 99% of your problem if you are. A wood blade is much to aggressive for thin sheet metal also. Order up a couple of 14T Bi-metal blades from McMaster-Carr or Graingers. I know you will see a big difference in performance with a good blade. Slow the saw down as much as you can when cutting thinner stock. Swap the belts to the slowest speed. Also crank up the belt tension as high as you can with your hand using the plastic knob.
I have one of these saws that I've been using for 24 years with no complaints... I guess I should buy it a beer next time I use it... :cheers:
Mark

BADVELLE

01-28-2005, 08:34 AM

See if this link works...
http://www.mini-lathe.com/Bandsaw/Bandsaw.htm#Table
Craig,
Are you using the original blade? I'll garauntee that is 99% of your problem if you are. A wood blade is much to aggressive for thin sheet metal also. Order up a couple of 14T Bi-metal blades from McMaster-Carr or Graingers. I know you will see a big difference in performance with a good blade. Slow the saw down as much as you can when cutting thinner stock. Swap the belts to the slowest speed. Also crank up the belt tension as high as you can with your hand using the plastic knob.
I have one of these saws that I've been using for 24 years with no complaints... I guess I should buy it a beer next time I use it... :cheers:
Mark

Hey Mark - Thanks for the input, I will order up the bi-metal blades. I am going to try this JET saw today. It looks alot sturdier than the HF 4x6 and I like that it has height adjust pads for leveling. Thanks again for the help.

parsonsj

01-30-2005, 05:59 PM

I picked up a new Ridgid bandsaw this past week (from Home Depot) and received Paul Ruggles' adaptation kit for it Thursday. I put it together in a couple of hours, and I've been cutting steel and aluminum all weekend with it.

I have two words: IT ROCKS!

I've retired my jigsaw (aka the metal terror) from metal cutting. The bandsaw cuts everything I've tried: 22 g steel all the the way to 3/16 steel. Plus some .060 and .090 aluminum. I get nice accurate cuts, and low noise and vibration. When I want to cut something, I just flip on the saw and cut.

Here's a couple pics. I gotta go cut some more stuff.

Highly recommended.

jp

baz67

01-30-2005, 09:02 PM

I was able to use this saw with JP this weekend. The only problem I have found is that it is not in my garage.

Brian

astroracer

01-31-2005, 02:59 AM

I picked up my new (used) band saw Saturday but haven't had time to put it back together and fire it up. It has a gearbox on the side and the motor and gearbox have step pulleys. I did get some measurments of the pulleys so I'll plug those into the SFPM calculations tonight. I just ran out of time this weekend to get anything done.
Mark

BADVELLE

01-31-2005, 06:12 AM

I picked up my new JET horizontal/vertical bandsaw on Friday, works great. I have been cutting steel all weekend on it. The workmanship and quality of parts is unbelievable for $260.

astroracer

02-01-2005, 03:03 AM

I worked on the new/old band saw last night, roughly calculating the blade speed SFPM. This saw is an older (1985) model but it has a speed reducer gearbox that actually gets the blade speed down to a slow enough speed that will efficiently cut steel. The speed reducer has a 17.5:1 reduction so I can play around with pulley diameters to slow it down even more if I have to. I’ll be pulling the gearbox apart to clean it and change the oil but the saw was well taken care of from what I can see and it did not see a lot of use. It was a killer deal for $132 dollars.
Working through the calculations I get a blade speed of 157.54 sfpm on the outer step pulleys and that jumps up to 231 sfpm on the next set. I will probably play with pulley sizes to get the cutting speed to around 170 or 180 sfpm. This will be a whole lot easier to do then I was expecting. I will not have to build a jack shaft system like John did for his saw. The gearbox was a pleasant surprise... :git:

JohnUlaszek

02-01-2005, 04:38 AM

Astro,
Sou nds like you got yourself a deal there. You might want to see if you can change a pulley to further slow your speed down as 150 is still a bit fast for sheet metal. If you can get around 80sfpm I think you will be happier with the results on the thin stuff.

astroracer

02-01-2005, 12:54 PM

My thinking exactly John. A 2" dia. pully will probably do it. I'll probably get a different step pulley with some smaller diameters and just swap them out when I need to. I'll get a little more accurate with my calculations tonite.
Mark

JohnUlaszek

02-01-2005, 01:42 PM

Astro,
Keep in mind a 2" diameter pulley may require a cogged v-belt. A standard v-belt might have trouble down to that diameter.

JohnUlaszek

02-05-2005, 02:23 PM

This picture shows how much a saw designed for cutting wood really needs to be slowed down, the first driven pulley is a blur compared to the final pulley that looks like its at a dead stop in this 1/60th of a second exposure.

https://static1.pt-content.com/images/noimg.gif

parsonsj

02-09-2005, 07:43 PM

I just gotta post one more time on this thread.

If you are doing sheetmetal work, and you don't have an upright bandsaw: GET ONE!!!

Tonight I made a couple of little filler pieces from 20g steel. They are no bigger than my thumb, and I made a template from heavy paper. I transferred the pattern, and cut the sheetmetal. I could not have done that with a jigsaw, plasma cutter, nibbler, or any other sheetmetal tool I've ever tried. The parts fit right into place the first time.

What a timesaver.

jp

baz67

02-09-2005, 10:36 PM

JP, too bad you have almost all of the sheetmetal work done now.

Brian

rolandska

06-14-2005, 11:18 PM

did this ever get anywhere other than the prototype stage? I'm still interested in doing it.

parsonsj

06-15-2005, 08:33 AM

I use mine all the time. Recently I changed blades and speeds (takes 3 minutes) and cut some .800 aluminum, some 1/4" stainless, and some 3/8" mild steel. Switched back to the sheetmetal blade, and cut 18g stainless sheet all weekend.

Head over to http://www.x1nova.com and drop Ulaszek a line. He can get you in touch with Paul Ruggles.

jp