Jeweler's saw question

[Rich Jakowski]

I resently picked up some blades for my old jeweler's saw frame and was able to cut some beautiful thin slots in the lock screws I've been making. I have a question, which may seem silly, regarding getting those thin blades taught enough to keep from curving when I'm making cuts. I've tried to pull the blade as tight as I can by hand before tightenting the screws, but there's still seems to be quite a bit of curve ocurring in the blade when I make the cuts.

Is there any trick to getting jeweler's saw blades really taught in the frame? 

[chapmans]

I always put the blade in the clamp closest to the handle then pull (spring) the top of the frame down and tighten the top clamp. I can get mine really tight with this method.
   Steve C.

[George F.]

For speaking for myself. I have the frame set for the blade that requires you to squeeze the frame closer to get the blade in providing the tension to keep the blade taught. Oh... a beer belly comes in real handy here to push on the frame while the other end is braced up against a block in a vise. ... Geo.

[Evil Monkey]

Mount the blade and tighten the clamp screws on both ends so the blade is basically 'installed'. Then, loosen the adjusting screw on the top of the frame (loosem it quite a bit) and push the frame ahead so as to tighten the blade. With the screw loosened quite a bit, the saw frame will tip a little when pushed tight. I wrap my trigger finger around the upright post of the frame (the post that goes from the rear blade mounting screw up to theframe adjusting screw) and push the frame ahead with my thumb on the same hand. This will put tension on the blade AND tip the frame as much as the adjusting screw will allow. Then, while holding the frame in this position (with trigger finger and thumb) as you tighten the adjusting screw, it pulls the frame straight and tightens the blade bowstring tight if that is what you desire.

[rick landes]

I am cautious of over tightening these fine blades...one does not want over do a good thing...

Rich, I have 3 questions on the curved cut
1 what type of blade are you using?...some are better for curving cuts and are some what tear drop shaped in cross section...others are strait and are a better choice for your slot cutting (I am assuming you are using the correct "teeth per inch" blade.)
2 are you using a good lube on the blade?...I really like the stick style lube made for high speed cutting (like CNC speeds) as these are easy to apply and are very durable
3 are you setting your piece into a vice so as to help facilitate a strait cut?...you may be the "problem" in that you may be slightly twisting the handle while stroking thru the full cut of the blade (do make sure you cut from end to end with the blade so as to wear the kerf evenly or you will break the blade on a tight spot)

I hope this helps

[George F.]

The blade selection is determined by the material and thickness. You seem to have a machinist's background, so you much pretty know that you need at minimum 3 teeth on the edge to cut well. I have bought my blades from Jerry Hudleston's recommendation of Rio Grande. I mostly use .064 . , .040 in brass and silver. and occasionally  mild steel and I use # 4,  and #6 The silver cuts real easy but a lube makes it easier, but still get broken blades in all materials regardless. For cutting out patchboxes and inlays where you have allot of turns and piercings you can expect broken blades often. I haven't purchased a lube, but I either use just split, or if I'm not to lazy to dig it out from my tool heaped work bench a toilet wax seal..... Geo.             Also, don't expect to cut exactly to the cut line, bring your finished work down by filing with needle files. I haven't tried blades with the rounded backs so I guess they would work good when cutting out a patch box or inlays.  As far as tightening the blade. you can only apply so much tension by using hand pressure. You want the blade taught and tightened securely with the wing nuts on the jaws and frame. Also remember that you have to loosen those wing nuts when you change a blade. If the blade comes out of the jaws even after tightening you might have a small piece of blade still stuck to one side of the jaws. I think that's it....Happy cutting!!

[Evil Monkey]

Perhaps this

I haven't tried blades with the rounded backs so I guess they would work good when cutting out a patch box or inlays. 

 explains this

For cutting out patchboxes and inlays where you have allot of turns and piercings you can expect broken blades often.

[George F.]

Blades get broken usually when they bind or get stuck. When cutting out a patchbox finial you;ll have to stop numerous times to reposition the piece in the vise so you can resume the cut. On piercings  again they get stuck. . Anytime the work has to stop and repositioned, you run a risk of binding the blade , sometimes the angle or the direction  aren't exactly what it was and as soon as you try to continue with the cut the blade  has a tendency to bind and break....Geo.

[Acer Saccharum]

You can use a shorter blade(either break it, or grip it shorter). Won't bow as much.

Also I have seen mini hacksaw style blades in some of the jewelry supply houses just for the jeweler's saw frame. Gesswein, Otto Frei, Rio Grande, I am not sure who has them.

A screw slotting file can be held in a jeweler's saw frame, available from Brownell's.

If you have a milling machine, then you can use the screw slotting saws.

I have run out of ideas.

[Hank*in*WV]

I use an old sharpening stone to break the  back edges of my blades. Seems to help make turns somewhat easier. This also helps on band saws and scroll saws.

[Rich Jakowski]

Hey Guys,

Thanks for all the helpful info. I guess the trick in getting a jeweler's saw blade tight is pulling back on the TOP portion of the slideing clamp which tightens the blade when the screw is tightened rather than the bottom part, which initially seemed more intuitive, but resulted in loosening the blade when the screw was tightened.

Re: Rick's question - The "curve" mentioned in my initial post was an up-down curve in the blade which occurred when I was cutting the screw slot because blade was too slack. BTW: the blades I'm using are straight and they cut beautiful, thin screw slots. The wax idea is a good one and does seem to make cutting a bit easier.

Thanks again to all who responded - this board is the best!

Rich

[Acer Saccharum]

You can buy the blades with the back edges already rounded for you. Gesswein. Ultra-Swiss blades.

[Birddog6]

I seldom have to worry about any of the above, as I usually break the blades just trying to get them into the saw !!   

[J.D.]

Is the blade set to cut on the pull stroke, or push stroke? Turning the blade to cut on the pull stroke will reduce bending of the blade on the cutting stroke, then apply the rest of the information presented in the previous posts.

[Rich Jakowski]

Always insert my blades to cut on the push stroke - it seems awkward, at least for me, to be cutting on the pull stroke.

[Acer Saccharum]

Ah, grass hopper!

ALWAYS have them cut on the pull! By cutting on the pull, you have a direct tension to the handle. Buy cutting on the push, the tip of the frame is pulling the saw through the work, and the frame will bend, causing a lot of flexing and bowing of the blade, in turn, causing breakage.

Saw with the blade vertical, so you're moving the saw up and down. The workpiece is horizontal. When you pull down to make the cut, the blade pulls the work down, onto the saw support. Also take your time cutting. Let the blade cut the kerf completely and cleanly, go slow enough so all the chips come out of the kerf, and that the blade can run easily up and down in the cut. If you try to cut too fast, the kerf is full of shavings which cause binding. A little soap or wax on the blade helps lube it, making it cut faster, stay sharper longer, less binding and breakage.

The saw support is nothing complicated. It's just a small board, 2 1/2" wide, maybe 5" long, with a long narrow vee cut in one end for the blade to run up and down in. Clamp this board to the table when using, or hold it in the vise.

T