Hogging Blades on Gang Rip Saws
Equipping a rip saw with a hogging blade can have advantages. October 4, 2007
Question
Does anyone use hogging blades on their gang rip saw to help eliminate some of the edge rippings? I'm just curious on how well they really work and how much time it saves on the back side of the saw.
Forum Responses
(Solid Wood Machining Forum)
From contributor T:
We use one on our gang rip, set up on the right hand side, which eliminates any small rippings. The savings are twofold. First, it chips the rip up and sends it right into the dust collector. Second, it is a great help to the person pulling the rips off the back of the machine. Not having to deal with small pieces that are waste anyway is a real plus. Since all of the waste or off-fall will now be on the left hand side only. It becomes a lot easier to separate the blanks from the scrap.
From the original questioner:
Contributor T, have you tried it anywhere else on your arbor? I want to try and separate our current setup using two arbors. I would like to eliminate virtually all the cutoff and eliminate all the separating and stacking of the sizes we use most. We use a 24 inch saw, so this would leave a little bit more arbor to use up. Any sizes that weren't usable within this setup would be set off to the side to be used with the second arbor setup. Our moulder sits behind our ripsaw, so the moulder guy could just pick the blank from the cart behind the saw and run it. I see no need in handling it twice if it's not needed. Any need to slow the feed speed down any with such wide blades? Currently running 150 fpm. Any chance of kickback?
From contributor C:
I am not clear on what you mean by two arbors. If you are thinking of a hogging blade on the guide side and one in the middle so that you have two arbor setups on the machine at the same time, one to the right of the middle hogger and one to the left, I see no reason why that can not be done other than the fact that it will reduce your max board width.
If your saw is a MJ or Progressive, it really does not care where the hogger is. It is just a matter of how you want to do it and what your widest random board will be.
Edging slivers are the worst kickback risk, so that should be reduced by half, but never forget that all gangs will kill you if you do not watch every little thing; thickness adjustment, thin lumber on one end, broken boards, anti-kickback fingers not maintained, bad rubber (on dip beds), and even then you are going to get kickback.
All gangs should be operated in such a way that the operator is never ever directly in the line of fire and that no other person can be in the line of fire, whether walking down the aisle or working in a nearby area. Shielding and fencing should be installed to prevent exposure to the innocent.
Before everyone lost their nerve and surrendered to China, there were literally hundreds of MJ's running with hoggers and most of them in the 125 to 150 ft. per min. range.
From contributor T:
Sometimes we use multiple hogging blades. Whether or not it pays to do so, or in the way you are talking about, is a whole different story. If you are buying random width lumber, no matter how the setup is on the machine, you will always get some boards that will fall in between the two hoggers and send a scrap piece out the back. If the lumber is not straight or has a lot of wane, that is another problem. The only way we have found that it works (using hoggers on the ends) for us is to buy the material width sorted. We don't do it a lot, but it can pay off. Some lumber companies will width sort to your specs if you buy enough. It has its pluses and minuses. If you buy it that way, you still get some waste on the edges. But the yield is higher due to all the boards being within a multiple blank size. If you have the ripsaw operator width sorting, he really needs to know what he is doing, since he is the one that will determine the amount of yield and the waste factor. He can either save you a lot of money or cost you a lot. A lot of times it is just easier to have the hogging blade chipping the right side up. Have a cart or, if you have the room, a conveyor handling the scrap and off-fall on the left.
I don't know what type of machine you are running. Unless you are running 8/4 or over, I don't see why you would need to slow the machine down. You can always make any speed adjustments. As long as the stock is reasonable, and the kickback fingers are maintained, you shouldn't have any problems with kickback. But it is always a good idea to never stand directly behind the machine, or have someone else work behind it. Accidents happen when you think they will never happen to you. So it is always good to take safety precautions.
From the original questioner:
Thanks for the info guys. Contributor C, the saw is a MJ, 24 inch. We keep three blade arbors set up most of the time for quick changeovers. Just trying to save a little more time on the backside.
From contributor C:
One large manufacturer in the South for years ran a line of gang rips with each saw equipped with two fences, one on the motor side and one in the middle of the arbor. He had a method of measuring the boards automatically and dropping the boards in the best machine on the best guide for that particular board width. So although they had only three gang rips on the line, in effect, they had six saws.
