4x6 Horizontal/Vertical Bandsaw FAQ
Originally written May 1999 by:
Seattle Metalheads Society
Uncopyrighted, use as you wish .. editing suggestions welcome!
Last modified April 2001
Summary: There is one machine tool that is found in many home shops due to its extreme usefulness and low cost. These are often referred to on the Internet as "$200 bandsaws" or "4x6 bandsaws" or "HF bandsaws" (this latter refers to Harbor Freight). It appears that, regardless of the name on the nameplate, that all of these saws have identical castings, and they differ from brand to brand only in minor cosmetic detail. (Addendum: There are actually two basic saws. The cheaper Harbor Freight model has stamped steel support brackets for the guides. The brackets are on the outside of the housing. The more expensive one has cast iron supports that lie in machined slots inside the housing. The housing is also a little heavier. The "better" model is ~$30-40USD more expensive. Some vendors also offer UL or UL/USA motors for extra money.) This FAQ is an incomplete by definition attempt to pull together some of the more useful references which describe different aspects of this saw, and how it can be modified to be more useful or otherwise more desirable.
1. BLADES - WHAT KIND
It has often been asserted that the stock blades don't work well. They won't take sufficient tension, they don't cut straight, they jump off the wheels .. I recommend Lenox DieMaster II blades or other high quality bi-metal blades. Expect to pay about 4X what the cheapest blades cost, and expect them to last 10X as long.
2. BLADES - HOW TO INSTALL & ADJUST
A. Band saw blades can be installed wrong way, watch out! Make sure that the teeth cut when the blade moves down towards the table. If they don't, turn the blade inside out and reinstall.
B. The bearings on the blade guides have adjustable clearance between them. One bearing is on a cam. Adjust the clearance until there is about .004" on either side of the blade. It has been suggested that holding a dollar bill so that it just clears both sides of the blade when setting the clearance will do nicely. Here is a paragraph I wrote once:
"My blade guide roller bearings were shot. They felt like they were full of metal chips, and they probably were. I got new ones for less than 5 bucks each. Installing them right is the first lesson. I installed the guide assembly on the saw, and then did the final tightening on the bearing shafts in place, with a feeler gage in my hand. The lesson is that these shafts are just slightly eccentric, like a camshaft. This is to allow adjustment of the bearings to just allow a .025" blade to run freely. I could not find a deterministic way to get them precisely located and tight simultaneously, so I just fiddled with it until the feeler gage felt right. Top and bottom, new blade guide roller bearings. What a huge difference!"
C. Tension - I'm a middle-aged guy, with hands no stronger than average. Here's what I once wrote about blade tensioning:
"I just got a new Starrett bandsaw tension gage. I tensioned and released the blade several times to make sure I knew what I was doing. I got the thing tracking perfectly and correctly tensioned. Now I won't ever have to use the tension gage on that saw again. Because I know that I just tighten it as hard as I can, using a shop rag to get a better grip on the 2" tensioning knob. I can just barely get it to 25,000 lbs/sq. in which is the lower end of the desired 25k-30k range. No way I could get it up to 30k. Maybe you are a bit stronger than me but I'd recommend just cranking the knob down *hard* with your hand and declare victory. Always had wondered how tight to set that blade. Hadn't ever had it tight enough before."
D. Wheel tracking - the wheels can be checked with a long straightedge to make sure they are coplanar. The lower wheel is not in any way adjustable, but the upper wheel can be moved in/out with shims (washer-like) behind the wheel. With respect to toe-in adjustment, here is what I once wrote:
"The top wheel runs on a shaft with oilite bearings. That shaft has a simple but usable toe-in adjustment which is a set screw. On the top of the main saw casting right below the tensioning handle are two 12mm bolts. I found that only the top one needed to be loosened to allow tensioning - the bottom one acts in concert with the set screw to control wheel alignment. (I may be still not completely understanding the two bolts and the set screw. Feel free to correct me.)"
3. MY SAW DOESN'T CUT SQUARE, WHAT SHOULD I DO
Suppose a piece of angle stock is clamped in the vise such that one leg is horizontal, and that horizontal leg lies flat on the saw base such that the vertical leg of the angle sticks straight up. If the angle is cut off then there are two possible out-of-square errors. One will show up on the horizontal leg, the other on the vertical leg.
A. Out of Square in the Horizontal Leg
This is fixable by adjusting the position of the fixed jaw of the vise. I have heard it suggested that a useful modification to the saw is to drill and ream a tapered hole when the fixed jaw is in the correct position to cut square, and to put a tapered pin in the hole.
B. Out of Square in the Vertical Leg
If the blade is in good condition and adjusted correctly, there are only a few things you can do. The cut can be out of square in two dimensions. One suggestion, presented by Terry Sexton in an article entitled "The Asian Connection" in "Projects In Metal" December 1993, is to measure the angular error, strip down the saw so the base is the bare casting, set up the casting in a milling machine and flycut the entire top of the base to remove the angular error.
A user found that after use the hinge pin had worn the previously
true holes in its mounting ears oblong. He made a permanent fix. You
can see it on his website:
There was an article by E.F. Wale presented serially in "Model Engineer" starting with the 17 January 1992 issue entitled "A Silk Purse" which also discusses this angular error, which suggests that it is possible to adjust the blade guides by loosening the nut holding the bearing assembly to the guide stem, tapping it to correct angular error, and retightening the nut.
Here is a recent thread from r.c.m.:
(QUOTED FROM PREVIOUS):"But, what you seem to be saying is that as the blade is swung down, it does not track vertically, but swings away from the vise. Unless you have used this saw A LOT, it is hard to imagine the pivot pin wearing enough for this, but it is possible. Otherwise, either the saw frame or the base has gotten bent out of square."
(RESPONSE):The later describes my problem, that is the blade is moving at this angle in free air, no cutting involved. I thought about the pivot wearing, but if that was the case, I would assume I could feel some play in it when it was moving. Actually, this was not the case, as the slight play I could feel with the saw vertical, went away as the saw came down. I think I have solved it now, one corner of the saw base was apparently a bit low, twisting the frame slightly, causing one end of the pivot to be a bit out of line with the other one, throwing tha axis of rotation out of 90 with the table. A bit of shimming the lower corner and all seems to be fine.
And the bandsaw manual does have a fairly clear description of adjusting the blade alignment, tracking, etc. I had checked and double checked all this, assuming my old blade was the problem, replaced it with a new one, all to no avail. Turns out the squareness of the base is very critical, guess its time to make a proper frame under it to keep my less-than-flat garage floor from throwing off my cuts again."
"Recall that the upper and lower blade guides use ball bearings on slightly eccentric spindles, which allow for adjusting the clearance between the guide bearings. Well, my saw was cutting WAY out of square, so I started down the diagnostic path. If you take the blade in your fingers and twist it slightly, the blade guides should be tight enough so that you shouldn't see the blade flex beyond the guides. One of my blade guides had come loose, and the clearance had opened way up. When I adjusted it and tightened it properly, the saw now cuts very close to square again.
So, if your bandsaw suddenly starts cutting out of square, check the clearance on your blade guide bearings first."
4. MAKE THE JAWS WIDER
Many users have modified the saw to have wider vise jaws. This can be done by adding removable "jaw liners" or by remaking the vise entirely.5. ADD A JACK SCREW TO THE BACK OF THE JAW FOR SMALL STOCK
If you try to cut off a small part you will soon find that it
is impossible to hold it in the vise as originally provided. The moving
jaw just rotates. Sometimes you have another piece the same size that
can be used at the far end. But a modification that solves this problem
is to add a jack screw at the far end. There is a picture of this mod
on Chris Heapy's Web page.
A user, writing on the subject of workholding in the 4x6, writes:
"When I have a work piece to cut that can't readily be clamped in the vise, I will use my Bridgeport T-slot clamp set to hold the work piece down. Simply pass the stud portion with T-nut attached though one of the slots in the table from underneath, then assemble the rest of the clamp components in the usual fashion. Some very large work pieces can be accommodated on one of these little 4" X 6" saws if you remove both the fixed and movable vise jaws. For short pieces of bar stock I use a 5c collet holding square fixture with the appropriate 5c collet for the work piece, then clamp the fixture in the saw's vise.
Another user proposes an alternative to the jack screw:
"I have one of the bandsaws sold under various names. Seems like I'm always looking for the right size scrap to space the vise jaws so I can clamp a short piece without the moveable jaw pivoting. (This description may only make sense to those who have used this saw.) I had this problem yesterday when trying to cut 3/8" off of a 1-1/2" bolt. Then I happened to look up at the rack of mill clamps and the solution hit me. I used two of the stepped riser blocks together to give the right length. Simple, wide adjustment range, and always close to my saw."6. ADDING STIFFENING TO THE STOCK BASE
Lots of words have been written disparaging the sheet metal legs as provided. There have been many published stiffening solutions. One is to provide a flat plywood "floor" beneath the saw, to add 2x4 braces at the bottoms of the legs, and to screw the wood braces down to the plywood "floor". This is also found in the article "A Silk Purse" (see above). Another is to cut plywood pieces in trapezoidal shape, and screw them into the large openings between the legs on either side of the saw.
Other suggestions include cross-bracing.7. REPLACEMENT BASE DESIGNS
Again, there are many replacement base designs. Rudy Kouhoupt has one, published in the Jan/Feb 1994 "Home Shop Machinist", called "Base for a Band Saw". There is an excellent and widely-cited design by George Carlson, Houston Home Metal Shop Club, which can be seen on their Web site. Reference
A user who has built the above writes:
"I built that stand, with a few improvements. The coolant system is a 5-gallon pail with a cut-off bleach bottle inside as a sediment trap. The pan has a "V" crease down the center, and is sloped, so the coolant drains quickly. A set of splash shields allow the use of coolant in the vertical position. A stub of 1-1/4" pipe allows the wires and hose to be routed through the pan directly under the saw. The axle of the original stand is recycled onto the new stand. The handle from the original stand is modified and became a hanger for the power cord. The saw is completely rewired with heavier gauge wire, and the coolant pump is on a separate switch that gets power only when the motor is running. The line cord is ~15 feet long."8. IT'S SO FIDDLY TO CHANGE THE JAW ANGLE
Chris Heapy suggests replacing the vise clamp bolts and nuts with tommy bolts and self-clinching nuts. See ref above.9. REPLACE THE DOWNFEED SPRING WITH A HYDRAULIC CYLINDER
One of the least usable aspects of these saws is their limited adjustability in controlling downfeed. The long spring is in many user's opinion quite difficult to adjust correctly, or to adjust at all. If you consider that the base of the saw (where the spring attaches) should be constrained during downfeed, to move only at a prescribed rate, it is possible to see that the spring can be replaced with a double-ended hydraulic cylinder. This cylinder should have piping between the two ports, and one path should have a check valve and nothing else. This will always allow the saw to be raised with little resistance. The other path should have a shutoff valve and a needle valve in series. It is very easy to change the rate of hydraulic fluid flow through a needle valve, and it is also easy once adjusted for a certain job to just use the shutoff valve to hold the saw in the "up" position.
There is an article by Jim Reynolds called "Sawfeed" in the April 1998 "Projects In Metal" which describes this modification in detail. This is the same setup used on some very expensive cutoff saws.
(Sept. 2000) There is now a company (Forem Tool) which is marketing a downfeed system for under $40. They appear at this time to be marketing it primarily through ebay, so go look up their current auctions (try the link here and look for an auction with the string "Control Device"). I have no idea how good this system is or how reliable the vendor is so don't think they're reliable just because you saw this!10. GEARBOX - HOW TO CHANGE THE OIL
It has been suggested that new Asian saws should have the oil immediately drained, and that the gearbox be cleaned with solvent and blown out with compressed air, to remove sand. The Jet owner's manual suggests that to remove the oil from the gearbox, that the saw be placed in the fully-down position. Then the 4 bolts holding on the gearbox cover should be removed, and the cover and its gasket should be carefully removed. A pan is then held under the gearbox, and the saw is raised. As it is raised, the oil will drain out the lower rear corner. I use 90 wt. gear oil in mine.
11. GEARBOX - WHERE TO GET REPLACEMENT WORM GEARS
Unfortunately the worm gears wear out in these saws. It has been reported that it is possible to order the worm gears that fit the Jet or Delta saws, and use these in saws from any importer.
12. MODIFY THE WIRING HARNESS TO ALLOW EASY REMOVAL OF THE TOP FRAME
This suggestion also is described in "A Silk Purse" (see ref above). It simply adds an automotive wiring connector such that the wiring harnesses of the upper and lower saw frames are separated. This allows the top frame to be removed without undoing the wiring.
13. MODIFY THE AUTO-OFF SWITCH WITH A PROPER LIMIT SWITCH
This has not been described in print to my knowledge, but this would certainly be a useful enhancement to these saws.
14. ADD A COOLANT SYSTEM
See George Carlson's design, ref above.
15. MAKE A MUCH MORE SOLID TABLE
See "A Silk Purse", ref above.16. BAND SAW FUNDAMENTALS
A highly recommended book is "Band Saw Handbook" by Mark Duginske.
17. RATTLY SHEET METAL
I discovered that the sheet metal blade guard which covers both wheels was kind of rattly and not perfectly straight. I was able to stop my rattle 100% by slipping a washer between the blade guard and the casting, right where the knob screws in to hold the blade guard in place. That put just the right amount of tension on it to stop the rattle dead.
Another idea is to run a bead of caulking and then close the sheet metal cover and let the caulking dry to form a flexible rattle-absorbing gasket.
To isolate the source of vibration, first try running the saw without the blade. This runs the gearbox and the lower wheel but not the upper wheel or the blade guides. When I did this I found that if I tightened the belt a little a lot of the vibration went away. Others have reported that better quality belts have helped. It is of course possible to remove the pulleys and balance them, to align them precisely, or to balance the armature of the motor itself. Unfortunately sometimes the source of vibration is in the gearbox and must be lived with.
A user wrote:
"I welded (2) 6" pieces of 1" x 1" angle iron under the plate that the motor is mounted to. This stiffens up the plate and reduces vibration considerably. It also lets you tighten the belt a bit more firmly."
Still another user wrote,
"Changed the motor pivots to a solid rod with collars on each end. Helps too."19. REPLACEMENT VISE HANDLE
One improvement is making a replacement vise handle that is heavy enough to have some flywheel inertia. I replaced the plastic factory handle with a solid steel disc of the same diameter. It makes a big difference in opening and closing the vise.20. MAKE THE SHEET METAL WHEEL COVER EASIER TO OPEN
One suggestion from a user reads:
"I modified the latch on the blade door. Just slotting the sheetmetal so the locking knob doesn't have to be completely removed saves lots of time changing blades. It is possible to retrack a jumped blade with the cover closed. Unplug the saw, loosen the tension knob, carefully restart the blade on the bottom wheel, retension blade."
Another, in response, wrote:
"You don't even need the slot. Remove the knob completely and bend the door edges so it 'snaps' onto the frame."21. IMPROVE THE DEPTH STOP (SUBMITTED BY NICK CARTER)
"The depth stop needs improving. I just finished the MK3, a bar of Al which slides along the 1/2" rod (file a flat on it for the setscrew which clamps it to the saw base) and clamps to it with a split cotter (MK2 had a slit and bolt for clamping) The other end of the bar takes a 3/8" rod which can slide back and forth as well, clamped similarly. The end of the 3/8" bar has a 1" diameter round which is tapped for 3/8-16 (as the end of the 3/8" bar is threaded) eccentric from center. This round is tapped 1/4"-20 for a small bolt which is what bears against the work. because it is eccentric, this bolt can be adjusted to where it meets the workpiece. Yes I'll take some pictures of it soon, because this likely makes no sense. Anyway the upshot is that two knobs control clamping and positioning of the stop, with the utmost ease."