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Hobby Band saw

4K views 31 replies 11 participants last post by  kolias 
#1 ·
I’m building a bandsaw as a hobby from a YouTube video which I modified to suite my needs. Most if not all the videos I have seen have two wheels but I want to used 4 wheels as per attached picture (2 wheels of 6”OD + 2 wheels of 1.5”OD). I have no experience with bandsaws and I wonder if it’s a bad idea to use 4 wheels instead of 2 wheels.

If successful it will be used for homemade crafts.
 

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#3 ·
I would say the alignment difficulty goes up exponentially with each wheel past two. But maybe you'll get lucky and it will work. If there's a way to do it with just two wheels I think you'll like and use the saw a lot more.

David
 
#4 ·
Now I understand the popularity of the 2 wheels and I agree. I will give it a try and if not successful (most likely I will not be!) I will switch to the 2 wheels.

To keep the same frame I figure I will need 7”OD wheels and the max. width of my cuts will go down to around 6.7”.

My thanks to both
 
#9 ·
You misunderstand, that quoted radius is of the CUT in soft wood. NOT the amount of side bend you can put on the blade.
The blade will break, again, and again, and again.
4 wheels... DOOMED to failure. (Theres a good reason why nobody in the world makes a 4 wheel bandsaw)
3 wheels... there are three wheel bandsaws, but they are notoriously difficult to get running properly.
2 wheels... theres a reason 95% of bandsaws have two wheels.:wink:
 
#13 ·
Nicolas...if your objective is a bigger throat opening, I suggest you make yours with bigger wheels and only use the usual 2-wheel configuration. Those smaller idlers will give you plenty of headaches as has been noted already. The brand name saws have extensive alignment requirements to run correctly...co-planar wheels, some with non-coplaner wheels...it all depends on the manufacturer. If you have a moment, check out "Alex Snodgrass' bandsaw clinic"...you'll get a pretty good idea of what you're up against with a 4 wheel configuration.

With 4 wheels you will need a way to align each wheel, otherwise your blade will go off-track when entering the upper wheel. You will not be able to align the blade on the two big wheels without being able to align the idler wheels...

Make bigger wheels and use only two...you'll get a bigger throat opening and eliminate all the alignment issues...
 
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#14 ·
Thanks Nick for the heads-up, the Alex Snodgrass' bandsaw clinic has a pretty good and useful info on my subject.

It’s true the idea was and is to have the max throat opening, not because I have a need for it but since I make a bandsaw from scratch why not?

As I mentioned I have scraped the 4 wheels setup and I already cut 2 new wheels 7.5” OD which will fit in my present bandsaw frame. All this work is experimental and if all works well I may make a new frame later on which will better fit the 7.5” OD wheels.
 
#17 ·
The problem with that is you have to get it perfect. Most bandsaws have a way to adjust the angle of the axle. That's how tracking is adjusted. Typically, the top wheel is mounted on a ring that is not hard connected to the frame and can be adjusted so the angle of the axle can be adjusted. In your case, the square plate would be adjustable.

Another complicating issue is you need to be able to adjust the blade tension (essentially the distance between the wheels).
 
#19 ·
I think you dont understand the sideways force that will be on the bottom wheel when you tighten the blade.
That wooden wheel will tilt out of that bearing shaft on the first use.

If youre going to re invent something that has been around for well over a 100 years, youre going to have a lot of failures.

Try following the expert;
https://woodgears.ca/bandsaw/
 
#20 ·
Guys I don’t try to re-invent anything, in my post #16 I was asking for suggestions on how to install the bearings and instead I’m getting more questions.

I’m aware of the woodgears site, an excellent site by the way, and I see how he installs the bearings on the wheel but he doesn’t show how the bearings are installed on the body of the bandsaw.
 
#21 ·
A 4 wheel bandsaw is definitely reinventing.

There are a lot of bandsaw builds on utube. study them. there is an unbelievable sideways force on the wheels when the blade is tightened. Large flanges are needed for wooden wheels, not just a bolt sunk into the wood. The same force is on the frame and can easily distort solid wood.
Mathias sells the entire plans for his, so he isnt going to give you all the secrets for free, but he also has the build on utube which shows you most of it.
 
#23 ·
I think Matthias has a few ideas on mounting the wheels on this page. I see he uses two bearings on each wheel, I guess that would make the wheels stronger and run more truly. I'm pretty sure he fastens the shaft, without bearings, to the frame. The more complex part is the blade tightening and tracking adjustment, which he also shows on that page.

So looking at your drawing (if you want to proceed as he did on that saw)... a start would be to take your bearing-mounting blocks and move them to either side of the wheel. I guess one of them will end up in the pulley. If you want to have the shaft rotating, I guess you should put reinforcement on either side of the wheel anyway - like a hub. I do think it makes sense to put the bearings on the wheel though (in the middle of the rotation). Then fasten the shafts to the saw. Where you attach the shafts to the body will also need to be reinforced. As Bob mentioned there will be a lot of sideways stress.
 
#25 · (Edited)
I understand this is an experiment and probably a fun and challenging project no matter how it turns out. A small bandsaw is a VERY handy tool.

You might visit a store and look at the shaft and bearings on that size hobby saw, which will give you a starting point. Bearings are pretty standard and available online pretty cheap. Once you find the appropriate bearing, I would ask the supplier about finding a shaft to mount it on. The bearing ought to be inside the wheels so the lateral forces are applied to the shaft mount, not the wheel itself.

Is the video on this on youtube? If so you can freeze frame the shots of the wheel mounting to get an idea how the designer meant it to be.

The design seems to have taken into account adjustment to make the wheels coplaner. Does it have a way to mount tires on the wheels. That slight crown on the tires is pretty important to tracking and setup.

My question is about the blade guides. They must be lined up properly so I think you're looking at Carter Guides for above and below the table. That will add substantially to the cost. I'll be interested to see the finished project.

If it fails to perform, won't hold adjustment, or other problems arise, consider buying a WEN saw, which is identical to the Rikon. The WEN saw uses a 72 inch blade, comes with proper Carter-style guides, and you can even get the Carter accessory guide for making very tight turns. Cost is $262 on amazon, even comes with a stand, worklight, and Prime delivery is free. https://www.amazon.com/WEN-3962-Two...id=1582910321&sprefix=WEN+band,aps,207&sr=8-2 The WEN is a 10 inch saw with a 72 inch blade. It is a step up from a hobby saw and with a half inch 4tpi blade will resaw--slowly--but pretty well.
 

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#27 · (Edited)
Found this pix of a shop made unit that has the bearings in the wheels. As mentioned above, I think that is the only way to keep them running true for more than a few uses. There are bearing installation tools, which you will probably find through a bearing supplier. The size of this tool will have to fit the bearing you select.

The pix also shows the guides are bearing type. I see that the 2 small wheels are to open up the throat for wider workpieces. Don't see any table tilt caplacity.

This pix suggests that larger diameter wheels will eliminate the two extra small wheels. I did notice on your pix that you have tires on the wheels, which is good. But I don't see where the bearings are located on your saw. I assume they are on the shaft behind the wheel?

If you measure the wheel diameter on a store bought saw, you'll know what size to make the ones for your saw, and you'll find standard tires that fit. Balancing the wheels may or may not be a problem. I assume you are using BB ply for the frame and wheels. Good and flat and I'd lilely add some extra ply to the back so you have some substantial frame structure to help keep the ply flat when you tension the blade. If you go with larger wheels, you might consider using a longer blade, such as a 72 inch.

Here's a video on using a home made hammer jig to install a bearing on a shaft.
 

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#28 ·
Now I got some really good answers, my thanks to all.

Please keep in mind this is a hobby project and the intention is not to save $$$ but to have the thrill and challenge of building something new. I have no need for a bandsaw but a small one which I built myself would be nice to have. To give you an idea when we are talking about stress the motor for this bandsaw will be a 24VDC, VS motor therefore before any stress occurs the motor will stall. I use the same type motor in another mini table saw I built last year with a 5”OD blade including the 2 trunnions and it works fantastic, cuts 1/4” plywood like paper.

TENGEES(Paul): I already have changed my design (which changes on a daily bases, lol) and have the bearings blocks on each side of the wheel. One item you mentioned and I never thought was to have the shaft thru the bandsaw body rotating or not. I have to think about it and decide.

DESERTRATTOM(TOM): I don’t have a video on YouTube but if successful I will do and post the link here. I don’t intent to mount tires on the wheels but I have a bicycle tube which I will glue to the wheels and I do intent to have a slight crown on them. It will help with the blade tracking. Regarding the blade guides I made a rough set for my previous design (4 wheels) and I attach a picture here. I plan to re build them later properly. Tom if my project fails I don’t intent to buy one but thanks for the link.

Much appreciated
 

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#29 ·
Just missed your last post Tom, thanks for taking the time to post the video.

You are right, on my previous design with the 4 wheels, the purpose of the 2 smaller wheels was to open up the throat. With the new 2 wheels design now the throat will be about 6.5” which is ok with me. I’m still experimenting with the bearings location and right now they are located on 2 hubs per wheel on each side of a wheel.

Yes I’m using 3/4” ply and I’m aware of balancing each wheel. The blade I’m using is 59” long, the smallest I could get for my needs and the 2 wheels I have now are 7.75” OD
 
#30 ·
@kolias Nicolas, thanks for the new info. Sounds to me like you've figured out a lot of this already. Looking forward to you posting a couple of updates as it progresses. It sure seems like an interesting project. If you get a chance, I'd like to see a shot or two of your setup for making the wheels co-planer. That would have to include both tilt and the up down adjustment for blade tension. It would also be neat to see the mini table saw, if you get the chance. Do you make small projects for the most part? Those are always of special interest to me.
 
#31 ·
No problem Tom, I will post picture as I go along but it may take some time since I do a lot of experimental work and I don’t work on this project every day. The blade tension is my own idea and this I have to experiment a lot. Here are 2 pictures of my mini tablesaw which I built from scrap wood around my small shop

On the 1st picture you can see at the left the “control panel” with ON/OFF switch, then the FWD/REV switch and the last is the variable speed knob 0-15K RPM. The fence, miter and Triton blade guard I had them from a 10” Delta table saw I bought about 20 years ago and I re build the top and used my own build fence and miter. I have two 5” OD blades, one is course cut with, I think 15TPI and the other is fine cut with 30 or 40TPI. The front handle at the bottom turns the blade UP/DN and the slot shows the degrees of the blade when I turn the handle I have on the right side of the box.

The next photo you can see the handle for the blade tilt plus the 2 trunnions I made. Took me a lot of tries to get them right but it was worth it. I have only one zero clearance slot where the blade comes out regardless of the blade angle. The ugly hole at the right serves to stick a vacuum hose when I want plus to inspect the blade. Rough dims of the box is 12"x16"x12" high all in 3/4" MDF. Only the top is 5/8" Ply.

If you need any more info, I would be pleased to help
 

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#32 ·
Finally got my hobby bandsaw working (the table top shown in the picture is temporary). The trick was to have all wheels shafts not turning and have the wheels with a good concave surface. Next to install is a permanent table top with a fence, my 24VDC motor and then cosmetic changes and painting
 

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