I did the hydraulic feed mod to my saw years ago I now I’m not sure it was a good idea. The problem is that hydraulic feed controls the rate of descent, but not the pressure. I seem to throw the blade more than when I had the old spring. I have to set the drop speed very low, or risk throwing the blade. Maybe this is due to another problem in my saw, but I don’t recall throwing blades when I had the spring, and I think it’s because the spring sets pressure, while hydraulics set speed. Any advice?

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I believe it is a very good idea, that's why it's utilized on every horizontal saw that is more sophisticated than the 4x6. What you are encountering is the ability to allow down-feed pressure beyond what the spring allows. I did this mod, but I have 2 control valves. One is a coarse adjustment to allow rapidly lowering the head to the stock. The other is a needle valve for fine adjustment of cutting rate. I rarely touch the fine adjust. Don't laugh, I know the cylinder is WAY overkill. Everything involved was stuff I had in inventory. Some of it for nearly 50 years.

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I have a needle valve as well. I can fine tune the drop speed with no problem. It's just that in order to keep the blade on, I have to set it VERY slow.

John

On Mon, Feb 17, 2025 at 11:38 AM, Len Sherman wrote:

It's just that in order to keep the blade on, I have to set it VERY slow.

I can cut with almost full head pressure on anything larger than about 2" wide. I had a few issues when I bought the saw but have not had issues for over a yeah. Maybe you probably have some blade alignment issues. My saw was sold by Harbor Freight and I can say with absolute certainty that many of there saws had the pivot point for the head drilled wrong. In order for the blade to cut through stock the blade guides had to deflect the blade downward. This is really a bad thing to do. The guides should twist the blade and and just touch the back of the blade, not push down. Your saw is not HF red so maybe this is not the issue.?

If anyone has this situation shoot me an email and I'll tell you how to fix it.

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Hi Len

Your hydrauic downfeed has no effect on the derailing of the blade, that's from some other fault. Hydraulic downfeed gives a much more stable cutting action which makes the blade is less likely to derail if anything.

In order to identify the problem you first have to know from which wheel (upper or lower ) that the blade derails from.? To do this remove the blade cover door from the sawframe (unscrew the two hinges) and turn the saw on and watch the blade.? Its designed to run so that the back of the blade just about touches (sometimes hits it and sometimes not) the rims of both wheels.

If its running so the back is clear of the top rim, then the tilt of the top wheel needs adjusting so the blade tracks properly (Slacken blade tension, then loosen the bolt that holds the top wheels axle, and screw the grubscrew below it in ~1/8th of a turn at a time, then tighten/retension and recheck tracking)

If its clear of the bottom rim but OK on the top, then its likely the outer bearing on the gearbox driven shaft has failed.? Tensioning the blade more will always make the blade run further from the rim, but if the bearing has failed (quite common) then not much extra tension is required to make the blade track off.? Conversely reducing the tension will make the blade track toward the rim. Changing that bearing is a bear but quite do-able.

Then set it cutting something on the slowest speed and watch which wheel the blade comes off first.

If tracking is OK and the blade only comes off in the cut then most likely one of the blade guides is too far forward on its adjustment slot.? This acts as a pivot when the blade starts cutting and levers the blade off one of the rims (usually but not always the bottom rim).

Let us know how you get on. Rgds - jv

On Mon, Feb 17, 2025 at 06:50 PM, John Vreede wrote:

Your hydrauic downfeed has no effect on the derailing of the blade, that's from some other fault. Hydraulic downfeed gives a much more stable cutting action which makes the blade is less likely to derail if anything.

John, you have a gift. I understand the saw but putting it into words and explaining it so that others can understand is another story. Joe Pi (on youtube) has this gift. I do okay, but certainly not as well as you!?

My saw was set up as you described at the end. The pivot point on my saw was drilled 1/4" too high. When the blade guide were set correctly, the end of the head hit the saw base before it completed the cut. Unless of course, the blade guides were pushing the blade down. The saw was set up to compensate for this defect when I got it and I destroyed 3 blades before I realized what the problem was. I ended up putting a 1/4" steel plate under the vise to resolve the issue.?

I ended up making these available. The one I have on my saw I made on the mill but I had a bunch laser cut. Judging by how many I have sold I'm guessing a bunch of Harbor Freight saws were made the same as mine.? The guy that laser cut this batch had a problem with the laser. The edges are rough so he gave me a good deal. If anyone needs a plate like this send me a massage and I'll sell you one fairly cheap.?