Size of metal to support homemade mill

[Georgia088]

My mill that I built a couple years ago and am still trying to make better (has a long way to go) has tracks that are angle iron. I originally put braces every 4' but quickly realized the angle iron flexed between the "feet" so I added more to make it every two feet. It is 20' long and each "foot" has a bolt and nut to adjust the height. It has worked.... but it's not easy to adjust the bunk to get it level because there is a foot every 2'. I was thinking I may buy some type of metal that I could weld under it that would span the full 20'. This way I could put jacks on the four corners to level the bunk.

Any ideas on what size metal I may would need? I mean assuming you've got the weight of the head and whatever size log on the bunk there will be quite a bit of weight I would imagine. I can cut up to about a 23-24" diameter log about 17' long. Not that I will cut anything that big very often but that would be max. This would also potentially make it so that I could mount it to a trailer if I needed/wanted at some point? Just wanting to see what yalls had to support them and what your thoughts were.  Would a 20' piece of 2x4 piece of steel tubing span this far?

Thanks?

[Hilltop366]

The "trailer" mills seem to use larger beams, perhaps 2" by 6" or deeper.

If the beams are strong enough you probably get by with 4 jacks, if they won't be in the way the jacks can go a ways in from the end and reduce the beam span.

[starmac]

It will be tough to use enough steel to just use jacks on the ends, if not impossible.

[Hilltop366]

Looking at the TimberKing mills with 2X6 beam, uses 6 jacks.

[Crusarius]

My mill used 2x6x.188 wall for the main rails they come from the supplier in 24' lengths. I welded a piece of 2"x3/8" flat stock to the outside face for the carriage to roll on. You can do that if you want to just build a new bed or you can just get the 2x6 and put it underneath it.

I do agree with that length I would prefer at least 3 jacks per side. 1 in the middle and the others in from the end roughly 24 to 36". depending on the layout of the bed depends on how you would weld the rails to the bed. Lots of options. The nicest thing about just using the 2x6 rails is that is the start to a very nice trailer.

If you want to see some photos take a look in my gallery. The mill is still under construction but I am pretty confident the bed is not going to be a problem

[Crusarius]

oops. I just reread you post and saw the 2x4 you are talking about using. The reason I chose 2x6 over 2x4 is the structural rigidity. with 2x4 you get quite a bit of twist in the bed. The 2x6 is better for resisting the twisting as long as your cross pieces are sufficient.

[Magicman]

Just keep in mind what a 3K - 4K (or more) pound log will do and also what happens when outriggers settle under that weight.  It doesn't take much to get ¼" of flex which does not seem like much until it is reflected in your lumber.

[Crusarius]

Magicman is absolutely right. That is part of the reason I choose the 2x6.

[GAB]

If you use two 24' long 8" x 8" WF I-beams, with 3/4" webs and flanges, and 4 supports on each side you should be OK.
Not knowing what your mill looks like, or how heavy it is, or how you load the logs on it, it is difficult to properly answer your question.
Gerald

[bandmiller2]

Georgia, a lot depends what you have for a foundation under your mill, if you have a solid concrete base and adjust your present supports its probably as good as your going to get. Is your mill stationary or portable.?? Portable mills require a much heavier frame. Frank C.

[Kbeitz]

When I build my mill i used 4" channel iron. Three on top of each other.
I also but 7 jacks on each side. I can still get a bow if the jacks aren't all
adjusted.



 

[Den-Den]

My mill has 4" channel with 2" angle underneath welded into a truss, depth of the truss is about 14".  Max length of log is just under 17ft.  Four supports (one on each corner) has been enough so far.  The truss arrangement is fairly lightweight and quite stiff.  I should have added more diagonal bracing between the two rails (will get around to it eventually) as the bunks do not eliminate side to side flex (just make both sides flex the same amount).
In hind sight, 2" x 6" rectangle tube would have been better as some extra weight would make loading logs easier when I have to winch them up ramps.  Even with 2" x 6" tubing, I still would add the truss brace underneath and install diagonal bracing.

[Gearbox]

Gosh a 24 ft . 8 x 8 3/4 X 2 he would need a Kenworth to pull it . You could truss it and be much lighter and just as strong .

[GAB]

Gosh a 24 ft . 8 x 8 3/4 X 2 he would need a Kenworth to pull it . You could truss it and be much lighter and just as strong .

I don't remember reading where he wanted it mobile.  So I made the assumption it was going to be stationary.
What you wrote is true however it will require fabrication time.  My suggestion minimizes that.
Gerald

[Georgia088]

It is not portable now. Although, I wouldn't mind working toward making it portable. It's just a hobby mill. I don't really wanna throw a whole lot of $ at it.  Here is an old pic from my gallery that you can see my bunk in.


 
This is not a very good pic bc this was at the start of the build and it doesn't look much like this anymore. Now there are supports every 2' and it's got adjustable feet. It's not sitting on concrete any more either. I will try and take a better pic tom. Thanks for all the advice. It's just a matter of if and when I wanna spend the money.  :D! 
The problem would be if I added something to be able to do this it would make the bunk higher and much more difficult for me to roll logs on. So, I would end up probably having to make some kind of log loader for the mill (which I would love to have) but again More time and $. Neither of which I have an abundance of. Maybe one day...
thanks again!

[thecfarm]

What are you using to move your logs around with now?

[Ljohnsaw]

A picture is worth a 1,000 words (old saying).  IF you are still on the ground with the bunks AND you have a way to roll logs on WITHOUT rolling on the track (small bridge?), I would keep it as you have it.  That angle iron should not flex under the weight of you head.  But, working that low is really hard on your back.  I did 2x4x¼ (IIRC) tube on my mill for 16'+ lengths of track with 2x3x¼" angle (3" upright) tacked on top.  These rails DO support the logs and have been quite good at supporting the load.  4 jacks set 4' in from the ends.

 

[redprospector]

I'm not sure it will apply to your situation. But when I built my mill I used 3" x 6" x 1/4" rectangular tubing for the main frame. 3 supports on each side. It served me well.
I figured I'd be better of to have more than I needed, than need more than I had. Besides that, my Dad always said; "Son, if you don't have enough time and money to do it right the first time, where ya gonna find the time and money to do it over?" Which makes me tend to go to the heavy side when I build things.

 

[Georgia088]

Cfarm
I just recently built this log hauler from a fork lift boom I had laying around. And a mobile home axle. I saw all the pics on the forum and needed a way to pull large logs in places I couldn't get the tractor. I have only pulled one log with it and it did what it was supposed to. My poor four wheeler is probably undersized but eh it worked.

<be>





 

Once I get it pulled up beside the mill I have found it pretty easy to roll the logs over the rail go the bunk with can't hooks. I've moved pretty large logs that way with no big problems. I also built a stationary thumb for backhoe that I can use to lift and set log on the bunk, but it's been easier just to roll them on really.

Ljohn

I like the fact that your 2x4x1/4 tubing has been strong enough to support the log weight. Is your bunk 20' total or 16'?

Thanks.

[thecfarm]

Reason I ask,I put my logs on two logs that I sawed flat on top,than I lay a piece of 4"x 3'x¼" steel from the logs to the saw bed and roll the logs onto the mill. A good idea to have the log bed a few inches higher too. Than I remove the metal and saw. Some have made like a hinge too.
Use what you have. I only saw for myself,so somethings take me longer,but not like I am trying to make money with the mill. I just want a building from my own logs.

[Ljohnsaw]

Ljohn

I like the fact that your 2x4x1/4 tubing has been strong enough to support the log weight. Is your bunk 20' total or 16'?

Thanks.

I have three track sections.  Two are 16'+ a few and one that is 8'6".  The cross supports are 44" long of 2x4x¼ on the ends and 3/16" in between every 4 feet.  When I want to do really long logs, I will have 5' sections of 2x3 angle hung between the sections and some 2x2x1/8" 5 foot long angle off the ends (to park the head each end) giving me a bit over 50' of log length I can cut.  The log bunks can be placed anywhere.  They are made from 5# channel on the bottom, 2½x2½x¼ uprights (that also hold the log stops of 2x2x¼) with some 2x3x¼ angle across the top.

[Georgia088]

Cfarm
I think I understand what you're saying. Youbasically build a ramp to get the log in the bunk? I have done that before with larger logs you kinda confused me with the metal piece though.

Ljohn
If I am understanding correctly, you habe 16' bunks with 8' spans between jacks.?

[Ljohnsaw]

Ljohn
If I am understanding correctly, you habe 16' bunks with 8' spans between jacks.?

Yes.  Made it so there was never much of an overhang. I just make sure to have a log bunk between the jacks (if just 1) or close to the jacks if one at each end.  Biggest log to date on it has been a 29" square log that my SkyTrak was working hard on.