First go at making a mini/rail mill

[BobL]

It's still been too warm to mill so I thought I'd start a new project - something I've had in my plans book for some time. This is part one of a rail or beam mill. My aim here is to make something that I can use to break up slabs into boards or beams but I may also use it to make cants so that I do not need to roll the log. I also thought I should show you what it looks like when I weld it up - warts and all - instead of the glossy job done by my BIL. Don't worry - even though it looks dodgy, it's plenty strong enough for what I want to use it for. Except for the wheels which I turned on the metal lathe at work everything else has been done in my shed - nothing fancy $60 stick welder, budget $20 angle grinder, and heavy duty drill press.



The design is based on a whole lot of ideas snaffled from here and there although I think my bar tilt correction mechanism may be an original idea - I never can tell because I look at so many designs. The frame is basically 1" x 3/16" angle iron which I did pay money for. The chunky metal blocks come from a bent heavy duty tow bar I picked up from the kerbside garbage pickup. The rests is craps from the scrap bin at work.

The base is designed to run on any flat board that is at least 1" thick and from 3 to 5.5" wide. Here is a view from the top.

The two nuts sitting atop the long slots, and the bolt at the back can be undone so the back wheel section slides out to accommodate wider boards

The brass wheels turn on 1/4" bolts and have 90º Vees cut into the rolling face. This stops the mill moving sideways and up and down. I'm trying without bearings to start with as it runs free and smooth but let's wait and see what sawdust will do.


The angle of the bar away from the vertical can be change by loosening all the allen bolts and the bolt atop the rear metal block then moving the bar to the desired position - usually vertical - this can be checked with a digital angle finder. The movement os very smooth allowing for fine tuning of the bar tilt angle.

The extent of the movement/correction possible is shown here.


Currently I have a basic bar clamp to hold the CS but there are a lot more mods/extras to be added yet including a design that connects direct to the bar bolts like otehr mills already out there.

 

[BobL]

Here is a little mod I added to enable the mill to sit very squarely on the beam.

It's very easy to get 3 wheels to sit in the one plane and I was toying around with just using 3 but then I decided to use 4! This is much trickier and so I came up with a little adjuster that varies the height of the 4th wheel to become part of the same plane as the other 3 wheels and stops the mill from rocking.

The allen bolts that some in from the top are connected to the 1/4" bolt used as the wheel axle because the cam like brass piece has a threaded hole so the allen bolt can purchase on it. By turning the small nuts on the allen bolts (they look like locking nuts) the nuts moves the wheel up or down - This works really well.


Will keep updating this as I add things to it!

Cheers

 

[Brmorgan]

I'm really liking the vee rollers there, Bob. I see some similarities to my design - same ideas carried out a bit differently, more or less. Note your first reply in that thread... FWIW, I haven't yet had any problems re: your concern in that post.

I hope you find yours as useful as I've found mine to be. There's something to be said for not having to turn the log to square it, especially some of the ones you have shown yourself working with. And now you have the 076 and 880, so you could set up one for the big mill and one for this one. Mine still needs some fine-tuning and a nice coat of paint, but it works. One thing I was going to add is a pair of set-screws on the bottom side of the bar clamp, one on each side of the bar. These could be turned in or out to fine-tune the squareness of the bar to the guide.

The set screws could be adjusted back and forth to very slightly bend the bar to cut square. An added benefit would be a second point securing the bar to the mill. I see that your mill has this adjustability built-in via the pillow block setup - good thinking there. Gives me some ideas for modifications.

 

[BobL]

I'm really liking the vee rollers there, Bob. I see some similarities to my design - same ideas carried out a bit differently, more or less. Note your first reply in that thread... FWIW, I haven't yet had any problems re: your concern in that post.

Cheers Brad. Yep, I have to admit I looked at yours for a long time and definitely got the pillow block idea from you. I have a fair bit of unistrut laying around and was going to use that as well but decided to slot the angle instead, just drill a hole at the end of the slot. Cut the slot out with my thin kerf cutting blade in my small table saw, and then close the slot end the end back up again with a bit of welding.

One thing I was going to add is a pair of set-screws on the bottom side of the bar clamp, one on each side of the bar. These could be turned in or out to fine-tune the squareness of the bar to the guide.

Humm . . . good idea but I'm not sure about whether that would work. - there would need to be a lot of stress on the bar and bar clamp to move it, plus the chain is then running permanently in a curved channel and that will wear the chain and bar in a non-standard way. The other design I have seen is rotating the clamp head itself but that mean teh saw MUST be kept vertical and it seemed at least as complicated as my correction method and I want to be able to use several variations of clamp head so I wanted the vertical correction done further back in the mill frame without having to build it into every clamp head.

 

[SilverBox]

I like it!!! Looks like it will work nice, but it seems like you'll probably be using a wider guide board most of the time, that smaller setting seems like it might be a bit tilty with a heavy powerhead attached.

 

[BobL]

I like it!!! Looks like it will work nice, but it seems like you'll probably be using a wider guide board most of the time, that smaller setting seems like it might be a bit tilty with a heavy powerhead attached.

Thanks SB. The biggest powerhead I plan to run with this is a 660 but mainly I will use my 441 to break up slabs.

The bits I have made so far should work on their own, but the eventual plan is this.


What I have made so far is the bit inside the striped box. The beam will consist of two 1.5 x 3" beams welded in a T-shape as shown or I might go for a 4 x 2 on top of a 3 x 2. With the V-profile wheels also gripping the beam underneath any tilt should be less of a problem.

Meanwhile I'm working on a bar bolt connector.

 

[irishcountry]

Looks great!! As always top notch! Doesn't look like that going anywhere heavy duty I was just thinking about why they don't use wheels on the granberg!! I have one on my b-day list which is pretty short so hoping to get one soon can't wait to try it out though yours looks much sturdier!! Get job have fun with it.. Take care irishcountry

 

[BobL]

OK - all prettied up in volcano orange with the 441 sitting on top.

 

[Brmorgan]

Looks good Bob. One thing I might suggest is to use some washers on both ends of the bolts on the bar mount squaretube sections. I initially used squaretube for mine, and the necessary tension to keep the bar tight eventually bent the ends all to pieces. Yours looks to be a bit heavier gauge material though, so it might stand up OK.

 

[striperswaper]

so how does it cut?

 

[BobL]

Looks good Bob. One thing I might suggest is to use some washers on both ends of the bolts on the bar mount squaretube sections. I initially used squaretube for mine, and the necessary tension to keep the bar tight eventually bent the ends all to pieces. Yours looks to be a bit heavier gauge material though, so it might stand up OK.

Yeah those bolts are also too short - I need to get some that are 1/2" longer so I can add regular and spring washers. I made that standard bar clamper so that I can use any chainsaw with the mill but I am also in the middle of making two different bar bolt mounters and will prefer these so I don't have to worry about bending the bar clamps.

so how does it cut?

Can't say since I live in an inner city block and the neighbors will go bonkers if I fire up the saw in the evenings - have to wait till saturday.

 

[Kicker_92]

Nice mill Bob, how do you think those rollers will do with sawdust buildup on the guide rails?

I'm not sure what your climates like there, but around here I've been having problems when it's raining with sawdust clumps on the guides for my Granberg Mini-Mill. The mill rides up on the lumps and throws the cut out of square.

 

[BobL]

Nice mill Bob, how do you think those rollers will do with sawdust buildup on the guide rails?

I'm not sure what your climates like there, but around here I've been having problems when it's raining with sawdust clumps on the guides for my Granberg Mini-Mill. The mill rides up on the lumps and throws the cut out of square.

Yep - that flag has been up for a couple of years since I first saw a mini mill in action. I have two proposed solutions.

1) I want to make a sheet metal cover that goes over the whole mill and the front edge of which has either rubber or brush wipers. We have these wipers on a big belt sander at work and they work a treat. You see those holes on the top of the black pillow blocks - they are ready for threading to hold the cover.

2) The bigger plan is . . .

This means I can then try cutting using the other side of the bar so the sawdust is squirted down instead of up.

 

[dallasm1]

[/QUOTE]
This means I can then try cutting using the other side of the bar so the sawdust is squirted down instead of up.[/QUOTE]

That would be an elegant solution to the upward blowing sawdust problem. The bottom wheels would hold the rig down as cutting with the "top" of the bar would drive the rig upwards. Great idea. Great thread Bobl.

 

[BobL]

That would be an elegant solution to the upward blowing sawdust problem. The bottom wheels would hold the rig down as cutting with the "top" of the bar would drive the rig upwards. Great idea. Great thread Bobl.

Let me throw in another idea for cutting up slabs or cants that can cut in reverse ie cuts down, a riving knife on sprung wheels (I'm calling this a RiveJig)



The frictional contact with the cant would be minimal because the saw is trying to lift itself off the cant
The vertical counter cutting tension could be adjusted by having a threaded knob on the top of the spring which could be adjusted as the cut goes along in case the cant varies in thickness .

What do you reckon?

 

[SilverBox]

This means I can then try cutting using the other side of the bar so the sawdust is squirted down instead of up.

LOL, that would be SO NICE.. Then I wouldn't have to wear my motorcycle goggles while canting..

 

[dallasm1]

Let me throw in another idea for cutting up slabs or cants that can cut in reverse ie cuts down, a riving knife on sprung wheels (I'm calling this a RiveJig)


The frictional contact with the cant would be minimal because the saw is trying to lift itself off the cant
The vertical counter cutting tension could be adjusted by having a threaded knob on the top of the spring which could be adjusted as the cut goes along in case the cant varies in thickness .

What do you reckon?

A couple of things. I think the force of the saw pushing up would mean a strong spring and as short a lever as possible, even perhaps one on each side of the bar. But the biggest problem I see is clearance on the bottom. I rarely have enough room under the log and often I sacrificially cut the log mounting timbers for convenience. Other times vertical blade does not even cut through the log entirely due to the size of the log. Trying to overcome that often leads design to the external frame setup (see Brmorgans great setup), losing portability in the process. Your top and bottom wheel design would lend itself very well to an external guide rail setup.

 

[Brmorgan]

For a really strong spring, go to a car mechanic and get an old truck engine valve spring. Or just one from a smaller engine for a more realistic compression.

I'm with Dallas on his thought about your setup being ideal for mounting on a more permanent structure, like a Logosol of sorts. That isn't to say that I don't also think it's ideal for a more portable application as well. In fact, I think that with some tweaking, that rig is very close to being a marketable product as long as it does't infringe on any patents from Logosol etc (I'm not familiar enough with their stuff to know). That setup could, in theory, ride on a very straight 2X4/2X6 just as easily as a metal guide. You could sell that unit along with a set of pre-made portable guide rails, or with a set of instructions to build a more fixed setup from dimension lumber or whatever.

I just wish I had the machining and welding capability at hand that you do. My neighbor is a machinist and can get some stuff done for me where he works, but I can't exactly have things done in short order that way. If I had a metal lathe and a TIG welder, I can only imagine what I would have come up with by now.

 

[Raymond]

Bob you do good work.
So tell me how did you get the wife
to leave you alone so you could build it?

 

[BobL]

Bob you do good work.

Cheers Ray!

So tell me how did you get the wife to leave you alone so you could build it?

I slip her a little something every now and then
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I do the wood work and she makes the jewelry!
Actually she's a mad horse rider so everything I do looks relatively "cheap as" !
"I Wanna buy an 880 !" - "Sure honey" - but her horse cost 10 times more than what the 880 cost!