another "machine" question

[sawyerkirk]

I need to build a gang saw relatively quickly, and am looking for some thoughts. It will be for cutting 4/4 green lumber into 1.5" wide stakes. one 5/8" shaft with 4 - 7" circle blades. My intent is to key the blades and the shaft.  all this powered by an 11hp briggs motor (came off my woodmizer LT25 many years ago. 11 horse big enough to power 4 blades thru green 4/4 oak?  any thoughts greatly accepted. oh yeah, I got the silt fence roller running great, now just waiting on some orders. soon as i can get my camera hooked up to this PC I'll send some pics.

[ADfields]

I think so.   A killer wormdrive framing saw is just under 2 horse so at 2hp per blade that would be 8 hp.   + the feed roler, belt drag and the fact that 11hp gas would be like 9 or 10hp electric motor I thing your just about right.  

Rather than key them and use spacers why not a 1" grade 8 allthread and a nut on ech side of the blade so you can ajust better?   Also why 7" blade and not 10"?   10" is about the same price as a good 7" and would stay sharp longer as well as make less heat.   My 10" 2hp table saw will cut 4/4 dry oak like butter so the power would be the same or even less at 10".
Andy

[Kevin]

I use my band mill for that ...

[sawyerkirk]

in my mind I was thinking it would require less power to turn the 7" blades, but I have an ever building stack of 10" blades from the chop saw so I would probably be wise to sharpen and use them, So far as the all thread, I had pondered that but was afraid it would not ride in the pillow block bearings right, I'll have to check into that in the morn. I like the idea though.
Kevin: I purchased a truckload (9000bf) of 4/4 oak/ash mix very cheap today. I have a customer that needs a truckload 1x2x5' stakes asap, so that's why I am going to build this thing instead of doing them on the mill. thanks, for the help. Kirk

[Don P]

The 7" blades will require less HP to my way of thinking, look at the length of the lever working against the arbor, from the outside of the blade to the rim.  Chuck up a 7" blade in your tablesaw and notice the feed pressure required to stall it, then try it with a 10" blade.
A 5/8 shaft that long is going to turn into spagetti in real short order. The blades can be machined out to 1-1/4". A shaft of that size, some spacer collars to go between them and then to a threaded end. Outboard of the threads the shaft can be turned to 3/4 and a flange bearing on a removeable, dowelled (located), plate that secures that end of the shaft yet allows easy blade changes. The inboard end would be a fixed collar, a 1-1/4" pillow block and then sheave down to the motor. The gang rip I used was along those lines with I think 12" blades and if I recall about 25 horses.
The old rule of thumb is 5HP per blade so you're low, but thats a smaller blade than they made the rule for.. ???. Heat may be a problem.

[ohsoloco]

Is there a future for more orders of this quantity?  If it's just one shot you could have them sawn by the time your new machine is built.  

Maybe I just wish I could build some of this stuff myself  :-/

I've purchased many pieces of woodworking equipment for a specific task, only to use them many times after the fact  

[ADfields]

It's true if you put a 7" blade on a saw set up for a 10" it will cut faster, it's turning faster at the tooth.   Turn them at the same speed (not rpm) and I know the 10" will cut beter and I think take a tad less power but I could be wrong on that part.   Geared to the right speed is the trick hear, biger the OD of the blade the slower RPM you turn it for the same cutter speed so the more tork from the same power suply I think.   True you have a biger lever but you would have more flywheel efect, also a flater cutting arc so your tooth is in the cutt for less distance witch is like cutting a thiner cut line.   I think the 10" would be a far beter choice and if you use 10's now it's not even a new size to get into.

The shaft I have in my head is 1" grade 8 allthread turned down to 3/4" on the ends and a keyway to fit a 3/4"id pullie on one end and 13" between the pillow block type bearings so you could gang rip 12X's with it.   Turning ends is cheep but cutting a keyway in an ID is a hole new deal and cant be done on a lathe or mill it's done on a key cutter witch is not found in all shops.   With the allthread you could change the setup with the nuts, have a chunk of MDF as a cover over the shaft hinged at 1 end so the blads can cut there own slots for ech set up.   It must be grade 8 and if you go past the 13" I would step up the size, 1-1/4 or 1-3/8 should do 16" or 18" with 4 or 5 blades I would think.   You should be able to use a tungston/carbide toothless type hole saw set up in a drillpress to cut new center holes in your sawblades, slow gowing but should work fine.   5/8" shaft just aint gona cut it with a span over 5" or 6" and the more blades you have the more tork load you put to it as well as deflection load, your talking about putting 11 horse power into that shaft remember.   Good luck.
Andy

[sawyerkirk]

Found a piece of 1.5" grade 8 all thread this morning. I'm going to take 6 blades and the all thread to the machine shop in town. I'll have the all thread ends turned down to 1"and the blades bored to fit the shaft. while this is happening I'll get my table built. I'll see if Ican get it all together by monday morn!! I canbuy 4/4 oak very cheap, the only problemis that they are mostly 6" wide, so stacking them up on the mill would be horribly labor intensive. If this first load works well, we will be doing many more loads just like it. also we will be able to use this for rippinddown most of our other stake material

[Kevin_H.]

Kirk,
You know you are going to haft'a post pic's of this beast...
once you get it done.

[ADfields]

  1-1/2" should handle all you can put to it!   Your gona need to cut down some grade 8 nuts so thay are not so thick as well.   And pix are shure in order!! 8)
Andy

[Larry]

I don't think 10" chop saw blades are going to work ripping green oak as they are made for cross cutting.  You might put one on a table saw and try it before going to the expense of boring the center holes out.

A true rip blade with something like 24 teeth will saw much easier.

[Scott_R]

If this pans out well for you I would recommend a six wheel power feeder for safety reasons. Not cheap, but cheaper than doctor bills. Scott

[sawyerkirk]

for a powerfeed I have a 1/2 hp motor turning an 8" tire,I just have to find the right speed. I have a gear box off an old lawn mower that I am goignt to try to implement in the power feed. the blades I am using are "combo" blades, I use them on my table saw all the time, but I am still waiting to see if they will rip large quantities.

[sawyerkirk]

well, I got it running this morning, without the power feed, that is a whole nother animal, I am able to push a 1x7x5' thru with little difficulty, althought that will get old quick, I still have to build a shroud for the blades and get everything alined. I need to find another good auction, I am running out of "junk" to salvage!! right now I have 6 10" blades on there, I think I will try the 7" to se what they do. I'll try to get some pics when it's complete. Thanks for all the help