So here's my take on quickly setting the angle to sharpen a knife, using the standard knife jigs (or also the Small Knife Holder). This is in beta... and comments/critiques greatly encouraged... (I know I'm not perfect). :o
First, as seen in the Picture 1 (right photo), I establish a mark on the inside of the wheel, where I can line it up with a chopstick attached to the handle, (use what I have lying around, haha). This becomes a reference mark where I can quickly move the wheel into an exact position each time. I tried a few other methods, but this was the most precise and fastest for me.
Second, I set up the wheel. After positioning the wheel on the reference mark, I used the the AngleMaster, set a blade at 15, 20, and 25 deg. and just mark the wheel at these locations, (left photo) (for the stone turning in both directions). I also mark the side of the wheel, so as the wheel wears, I can remark the face (or just use the side) as needed. (Sharpie lasts quite a while, even on the face). (I was surprised I had to make a set of marks for each direction... more on that later).
Picture 1
(https://image.ibb.co/nxNuEa/IMG_1211.jpg)
Once this is done, as seen in Picture 2, I can now clamp a knife in the jig however I want, or use the Small Knife Holder... (the length doesn't matter). Once clamped, I simply rotate the wheel to the reference mark, lay the clamped knife between the wheel and Universal Support, then slide the Universal Support in/out to line the edge up with the line at whatever angle I want to sharpen at.
Picture 2
(https://image.ibb.co/i7eKfF/IMG_1209.jpg)
Anyway, so far, so good. I tried several knives, and after a little practice, was able to quickly hit the angle I want, and also "rehit" an angle, without issue. Checking with the AngleMaster occasionally since then... it's shown to be pretty accurate.
But, here's the question I have. There is a big difference in distance between the markings sharpening edge trailing vs. edge leading (stone turning away from or into the blade), as seen in this photo...
Picture 3
(https://image.ibb.co/mcPo7v/IMG_1214.jpg)
... I remarked the stone in a different area, and went to 30 deg., just to show a bit better. (The side view just shows how I mark the side of the stone, making remarking the face as needed easier, or just use the side as the guide).
My question is why... or am I doing something wrong? I've tripled checked the settings, and also verified them by setting the Universal Support based on the chart in the "Grinding Angle Adjustment" booklet. The distance between the Universal Support is the same both directions, the grinding angle is the same both directions, the distance (in testing) between the Adjustable Stop and the knife edge is the same... so why is there such a difference in the distance of the markings? Probably something obvious I'm overlooking... but want to make sure I'm not doing something incorrect. (This really surprised me, and if I'm doing something wrong... can't figure out why it works...).
Any other comments/suggestions appreciated. I did this prior to finding the "Grinding Angle Adjustment" booklet, (and was pleased things matched up once I figured out 'S'...), and am thinking there's probably a different way to set the wheel markings (math) that may be more accurate? But so far this has worked, and I would think easily repeatable. Obviously you can mark whatever angles you want, use a different reference, etc... so any ideas welcome. (Or if this was done somewhere before, point me that way...).
Hope it helps, (and makes sense). :)
Thank you for posting your angle setting method. Good food for thought!
Jan
Interesting innovation, CB.
These different ideas all seem to have a common thread. While the Anglemaster works very well with larger flat areas, like chisel bevels, it can be difficult to use with small bevels, like knives. Very good lighting can help this, however, a small beveled surface is still small.
I believe the ideal situation is for a sharpener to become fluent with all of these methods and have a variety of techniques at his fingertips.
Keep exploring; you are doing good work.
Ken
Comments may take a little longer to formulate. My last millenium mental processing unit does not have warp drive.
Thanks for the replies.
I think I solved the distance issue. I had assumed that the positions for the horizontal and vertical Universal Support positions were essentially a "mirror image"... so thought the distances should be the same.
But in looking at it from the side this a.m., I realized that the horizontal bar is above the center of the stone, while the vertical bar is behind it (in relation to where you're sharpening. So, the distance to reach 90° is greater on the horizontal side.
I agree that learning various methods/techniques are ideal... or at least trying them and see what works best for your particular situation. All the various methods I've seen on here are great.
You are correct, the USB sleeves are asymmetrical with respect to the shaft, but I do not see a problem here. I am wondering if your method can work correctly with arbitrary distance between the Adjustable stop and the knife edge (projection length).
Jan
Interesting observation about the position differences in the horizontal and vertical sleeves (Tormek's word). That is useful information; good seeing!
We keep pushing back the frontiers,
Ken
Quote from: Jan on July 14, 2017, 05:01:59 PM
You are correct, the USB sleeves are asymmetrical with respect to the shaft, but I do not see a problem here. I am wondering if your method can work correctly with arbitrary distance between the Adjustable stop and the knife edge (projection length).
Jan
Not sure if this answers your question... but as a test of what I think you're asking, I took a knife and mounted it in the standard jig, and set a 20° bevel (checked with the AngleMaster). Then marked the bevel with a Sharpie, and remounted it in the Small Knife Holder. This time, set the 20° angle using the mark on the wheel, and then turned the wheel by hand, to see where the Sharpie was removed. Looked to be pretty much spot on? (Picture attached).
Thanks for the question.
Thank you for this test! It shows that your method works for various distances between the Adjustable stop and the knife edge.
Jan
Well, it didn't work on the top (vertical) support. I repeated the same test... mounting the knife in the jig everything lines up (20° line, AngleMaster matches). But when I put it in the Small Knife Holder, and set the 20° angle using the mark on the stone... the actual measurement is around 23-24°. (I repeated it several times... seems consistent).
Not sure why it all works on the horizontal support, and works with the knife mounted in the jig on the vertical support, but not in the SKH. Hmmmm.
Thought I'd pass it along. More testing. (Ideas welcome). ???
Well dang... it doesn't work after all. (Or, sorta works, by coincidence). ???
After staring at the diagram in the "Grinding Angle Adjustment" booklet... and sliding the Universal Support in and out with a ruler laying across it, it's apparent (rather obvious in hindsight), that the angle changes.
So, I simply laid a ruler between the Support and wheel at a mark, and measured the angle change with a digital gauge. Turns out, on the horizontal support it's not that significant. I didn't measure, but 10 turns of the Micro Adjust is only a degree or so. (And most of my testing was done this way).
But the same change on the vertical support is around a 5 deg. difference. (Probably due to the Wheel/Support relationship I mentioned earlier).
So, guess if you sharpened off the horizontal support, and there wasn't a significant change in "projection length"... close enough to get away with? :-[ Might be close enough to consider... it's a quick way to do it.
Thanks for the feedback... gave me a (needed) different perspective to look at it.
(Freehand looking better and better).
Thank you for your explanation. You are a fair person. I will sleep well now. :)
Jan
Haha. Please don't lose sleep on my account.
I like to experiment... they don't all pan out. (Bummer it was the first one in this forum)...
The wheel sometimes throws me a curve. ;)
Welcome to the club, CW. I have two small knife platforms which didn't work very well. (I used the platform jig; Herman's design with the platform of the scissors jig works better.) I have a spare microadjust nut from a project to use it as a lock nut - another not so brilliant idea, as well as a bunch of also ran parts from other ideas.
However, I also have several kenjigs, which, in my humble opinion, work well. Innovation is a mixed bag. Keep innovating!
Ken
Thanks.
There goes my dream of selling CRPs (Chopstick Reference Pointers).... :'(
Don't get hung up with minor details; lots of things don't actually work. :)
Ken
Quote from: cbwx34 on July 13, 2017, 11:00:15 PMFirst, as seen in the Picture 1 (right photo), I establish a mark on the inside of the wheel, where I can line it up with a chopstick attached to the handle, (use what I have lying around, haha).
Brilliant idea!
If you remove the grindstone and lay it down flat so that you can measure the angles between the radial lines, do they match what you got using the Angle Master measurements?
There is some advantage to using a pointer and reference mark to quickly index the wheel to an exact position. I tried a couple of other ways, but I'm sure as most of you here already know, it doesn't take much change to affect the angle, so it has to be pretty "dialed in".
Not sure about measuring the angles as you're asking? If you're thinking along the lines of how Steve Bottorff marks the wheel... no it won't measure in that way. As has already been shown though... the angle part of this is a bit of a bust, since the "projection length" affects the result.
Still, I'll probably pursue this off the horizontal support... since the error isn't too significant, and for most knives it wouldn't matter. Maybe get a better idea of how the projection length affects it. Off the vertical support though, I'm thinking it might be too large to quickly adjust for. It could be dealt with... but would probably be simpler at that point to just use the AngleMaster.
Quote from: cbwx34 on July 15, 2017, 01:45:41 PM
Not sure about measuring the angles as you're asking?
I'll post some pictures of it when I get a chance.
Two years ago I have modified the TTS-100 for Knife jig. https://forum.tormek.com/index.php?topic=2639.30
It was designed for kenjig projection length 139 mm and bevel angle 15°. Later bevel angles 10°, 12.5°, 17.5° and 20° were added.
First picture shows my prototype. The second and third picture show more advanced versions manufactured by my friends from a local knife.cz forum. The last picture shows a setter printed on a 3D printer.
Jan
Jan,
I really like the 3D printer version of the jig. It is simple, direct, and seems very cost effective to me. All three of the jigs you show auto correct for grinding wheel wear. That is an improvement over my very simple baltic birch plywood jigs OVER THE LONG RUN. My plywood jigs can be corrected for wheel wear, however, this requires very occasional adjusting by lengthening the groove. This is a simple procedure, but is not automatic. The two bearing wheels do this elegantly. Tormek designed and patented the two point compensation. It is incorporated into the TTS-100 for turning tools and works "a treat" (UK English idiom for very well). I have never understood why Tormek never expanded this technology for other tools.
Tim, be sure to read the entire topic Jan referenced. It begins with photos and a description of my Substitute Target idea. The Substitute Target is a rectangular piece of flat metal 1.25mm thick. The thickness corresponds with the native groove of the knife jig. When substituted for a knife in the knife jig, and set for the 139mm Projection, it provides a very user friendly large flat surface for the Anglemaster.
The common thread of all these jig setting ideas (yours, mine, Jan's, et. al.) is to provide a repeatable, accurate, less tedious option to using the Anglemaster. I include the black marker in this group. The Anglemaster is a useful, essential tool. It works very well for setting up large, flat surfaces like chisels and bench plane blades. It can be tedious for small bevels such as knives. STRONG LIGHT IS ESSENTIAL! If the lighting is your work area is less than superb, a good LED flashlight or magnetic light can make life more pleasant.
I generally try to limit my use of the Anglemaster to the first set up of a given tool. Even then, I try to use the black marker method or Dutchman's tables. Once you learn how to use them (they are not difficult), they become an invaluable resource. I prefer to use simple kenjigs for repeat sharpening.
I encourage you to continue developing your chopsticks technique. The mental exercise is good and future more successful results may await you, often in unanticipated ways. I had an idea to use Robin Bailey's extended support bar to use the horizontal sleeves in a grinding into direction. (This would simulate dry grinding technique with a Tormek.) My idea was brilliant; it just didn't work. Water cascaded from the trough. oops....... I revived the idea when I started wirking with CBN wheels. They can be used wet or dry. Used dry, the extended support bar worked very well.
So, do not forget your ideas. They may prove useful later.
Keep thinking!
Ken
Jan... thanks for the link. I'm reading through the whole thread, so may take some time. (Also some of your pictures seem to be missing, which, while not impossible, makes it a bit harder to follow).
Just out of curiosity... has anyone ever just marked the Universal Support to quickly set the distance? It would seem that marking the support might be an alternative way to set it vs. the Kenjig. (BTW, I don't at all think the Kenjig is a bad idea... just thinking of a way of setting multiple distances). My idea would be to mark it, for example, with a letter indicator, that could then be matched to the chart similar to the "Grinding Angle Adjustment" booklet. Then as the wheel wears, flip the page to show the new dimensions, and corresponding letter. Initial setup might take a bit of time, but once done, it would last as long as the machine. Just an idea. :)
Edit to add: In thinking about the "Kenjig" a bit more... if I were to insure that the knife is set at approximately the same "projection length" (which the Kenjig requires anyway)... then I could use the marks on the wheel (in either direction) to set whatever angle I would want as I was doing before... correct? I just need to include the projection length into it, (and no need for the actual jig to set the support distance).
(Don't let this detract from the "marking the Univ. Support" question though, still curious about that too).
Cbwx, I am not aware that anyone has marked the USB. I think it is a good idea. :)
Wootz, a very inventive Australian sharpener, posted an interesting angle setting method based on the height of the USB above the Tormek housing. It may be inspiring for you. https://forum.tormek.com/index.php?topic=2969.msg15703#msg15703
To your last question: the bevel angle is generally defined by three variables, e.g.
1) wheel radius
2) projection length
3) USB – stone distance.
I sharpen for many food service operations and do from paring knives to chef's
and long slicers, cleavers etc. The more jigs the better so you don't have to move the support arm.
I sharpen away from a knife and am able to look down on my work easily. I identify a point on the top right tightening knob (T8) and set it as my standard 15 degrees to set up a knife.
I can adjust from the jigs for many knives from there and add secondary finish bevels just by turning the jig end a turn clockwise.
Same concept but I'm just setting a different reference point and eyeballing. Still need to move the arm for some work but minimizes it.
Best Wishes
Tim
Tim,
Here is a link to Robin Bailey's extended support bar for the Tormek. It is both taller and longer than the Tormek version. For routine work, I use the Tormek bar. For my Chinese cleaver, Robin's bar is "just the ticket". If I had long slicers, I would use Robin's bar for them, too.
Must dash..more tomorrow.
Ken
https://www.sharpening-service.co.uk/onlineshop/prod_4360851-Tormek-Extended-Universal-Support-Bar.html
I may be glad Part 1 "failed", 'cause Part 2...
(https://image.ibb.co/mnjbZk/IMG_0631_2.jpg)
... coming soon! ;)
(Get your red "grading pens" ready!)
(Plus, I may need help "dialing it in"... if it turns out it's even feasible). :-[
So, the next version may turn out no better than the last... definitely would have to take "quick" out of the setup.
(https://image.ibb.co/i5tFVQ/IMG_0004.jpg)
My thought was to "approximate" the slope of the stone in the angle area most commonly sharpened at for example 15˚-25˚ (I know it's not a real slope, but hopefully get the idea), which would allow for a quick angle change. Anyway, it works... but I can't find any real rules for the setup... just sort of hit/miss to dial it in. And since there's several variables to account for (distance of base support, angle of 2nd support, projection length, wheel size, etc.), that changing one starts it all over. (And only works on the horizontal support... not seeing it on the vertical). If anyone has any idea on dialing it in somehow... love to hear it. After many trials, I can occasionally hit on a setup that works well... (or I can just set up for one particular knife and angle, which isn't that hard, but not 'quick')... but change one aspect, and it throws it all off.... :(
Problem is, I like the setup... where it puts the knife in relation to the stone (and me)... very comfortable position and dynamics to sharpen with. There's some other "logistical" issues (for example, probably need a longer base Universal Support), but not to that point yet.
I read the link to the other thread Jan posted (several times)... to be honest, can't totally figure it out. I understand it in principle, (sort of I guess), but can't for example figure out where the "29.3" measurement comes from? Anyway, if there's a clue in there to what I'm doing... not seeing it. Guess my math skills are rusty... :-[
Still working with it though... input appreciated! :D
Cbwx, congrats, it is a very nice setup which is based on original Tormek components only! :)
It works correctly for horizontally positioned blade and properly oriented grindstone with angular marks. The blade horizontality may be a minor difficulty of this setup's because it may require to adjust both USBs when the projection length has changed. The adjustable stop may help to avoid the necessity to change the USBs setup.
Please be so kind and remind me where I have used the "29.3" value you have quoted. I have already forgotten where it was. ???
Jan
Jan,
Do you still have access to the file you used to 3d print the jigs that you made?
I have neither the file nor the setter. It was prepared by my colleague from a local Knife.cz forum. I use the aluminium model with contact ball bearings.
Jan
Quote from: Jan on July 24, 2017, 09:51:59 PM
Cbwx, congrats, it is a very nice setup which is based on original Tormek components only! :)
It works correctly for horizontally positioned blade and properly oriented grindstone with angular marks. The blade horizontality may be a minor difficulty of this setup's because it may require to adjust both USBs when the projection length has changed. The adjustable stop may help to avoid the necessity to change the USBs setup.
Please be so kind and remind me where I have used the "29.3" value you have quoted. I have already forgotten where it was. ???
Jan
Thanks. It is one of the goals to sorta "stay within the system".
The "29.3" was from this post by wootz https://forum.tormek.com/index.php?topic=2969.msg15686#msg15686 (https://forum.tormek.com/index.php?topic=2969.msg15686#msg15686) (from the thread you posted the link to earlier).
The distance 29.3 mm is measured from the shaft central line to the base of the T7 housing. Wootz uses the name "constant vertical" for it.
It is a pity that Wootz script disappeared from the thread. Let me know if you are interested in it and I will try to find a copy.
Jan
I have found studying past posts an invaluable source of information. Wootz is very innovative, and also does a very good job of discovering and evaluating things. In his posts he discusses variations on the universal support, including Robin Bailey's extended supportand Tormek's US 400, designed for the Tormek 4000, a specialized machine (now out of production, and predecessor of the T2). I have found Robin Bailey's support useful and plan to purchase a US400. I have heard that Tormek plans to make a limited production run of them.
My main frustration with the forum format (all forums) is that some valuable information is ephemeral, and quickly disappears into the past. I have made printed copies of some posts; I wish I had done this more extensively.
Ken
Quote from: Jan on July 25, 2017, 12:28:42 PM
The distance 29.3 mm is measured from the shaft central line to the base of the T7 housing. Wootz uses the name "constant vertical" for it.
It is a pity that Wootz script disappeared from the thread. Let me know if you are interested in it and I will try to find a copy.
Jan
Thanks for the additional info. (I don't think I can use the script).
Quote from: Ken S on July 25, 2017, 01:01:01 PM
I have found studying past posts an invaluable source of information. Wootz is very innovative, and also does a very good job of discovering and evaluating things. In his posts he discusses variations on the universal support, including Robin Bailey's extended supportand Tormek's US 400, designed for the Tormek 4000, a specialized machine (now out of production, and predecessor of the T2). I have found Robin Bailey's support useful and plan to purchase a US400. I have heard that Tormek plans to make a limited production run of them.
My main frustration with the forum format (all forums) is that some valuable information is ephemeral, and quickly disappears into the past. I have made printed copies of some posts; I wish I had done this more extensively.
Ken
I'm interested in the US400... please keep me posted. (I think the one from Bailey is no longer available).
Definitely a lot of good info in previous threads!
Some two years ago I have posted about my flat platform prototype. For blades of the same thickness you set the bevel angle only once. You can sharpen in both directions. https://forum.tormek.com/index.php?topic=2562.135
It works fine, but currently for some reasons I prefer to sharpen using the knife jig guided by the USB. For angle setting I use the kenjig concept.
Jan
Quote from: Jan on July 25, 2017, 08:43:26 PM
Some two years ago I have posted about my flat platform prototype. For blades of the same thickness you set the bevel angle only once. You can sharpen in both directions. https://forum.tormek.com/index.php?topic=2562.135
It works fine, but currently for some reasons I prefer to sharpen using the knife jig guided by the USB. For angle setting I use the kenjig concept.
Jan
I saw that... (and in fact was just writing a post related to that). ;)
Setup.... Part 3?... :o
I've pretty much settled in on using this as my current setup... sort of a combination of several ideas. (See attached picture).
- The USB that the knife jig rides on, moves straight up and down in the vertical holder (left side of top pictures). I got a 500mm bar, and attached it to the upper USB, for enough length to sharpen using the knife jig.
- I sharpen with the knife level, using where it contacts the stone to set the angle. Since I'm sharpening with the knife level, I can set it with a digital angle gauge (as in the picture), or, I also measured the distance between the 2 USBs for various angles, and can just set it with a caliper.
- I use a laser as a guide, so I maintain the angle by sharpening just below the laser line. (From the Laser Guided (https://forum.tormek.com/index.php?topic=3329.0) thread).
- I removed the stop collar on the knife jig... this allows me to keep the knife along the laser line. (Basically a "guided freehand" or platform guide - similar to other guided sharpeners). (Shown in the bottom 3 pictures). (From the later posts in the "To pivot or not to pivot" (https://forum.tormek.com/index.php?topic=2589.0) thread).
- I can easily move it between the T-4 and the "Supergrind" as needed.
Anyway, so far, so good. ::) The nice thing is, if you're sharpening several knives at a set angle, there's no need to measure or adjust anything. I did that yesterday... sharpened a block of knives at a friends house, various shapes & sizes all at 15 deg. Just clamp the knife and start sharpening (and the belly/tip setup isn't as critical, within reason, since there's no real pivot). (I'm still debating this setup vs. the setup I had in Reply 25 (https://forum.tormek.com/index.php?topic=3323.msg19951#msg19951)... with some modifications I have here). (Still a Work In Progress). :)
One little "bonus" of sharpening with the wheel turning away... the water never "rides up" on the knife and travels down the blade... less mess. 8)
Comments/feedback welcome!
So, is there still some combination of lifting and pivoting depending on the slope from the belly to the tip? Or do you keep it flat and just pivot to stay at the line, since there's no collar stopping you from moving it further forward now as you rotate?
It's a very interesting approach to changing the "angle of attack", so to speak, to make the process more comfortable. .. But man, that's a LOT of parts to combine for this setup lol
Quote from: Kavik on August 30, 2017, 06:35:28 PM
So, is there still some combination of lifting and pivoting depending on the slope from the belly to the tip? Or do you keep it flat and just pivot to stay at the line, since there's no collar stopping you from moving it further forward now as you rotate?
It's a very interesting approach to changing the "angle of attack", so to speak, to make the process more comfortable. .. But man, that's a LOT of parts to combine for this setup lol
Depends on the knife, but the short answer... most knives I can just rotate the knife, keeping it parallel (or "flat"), and keeping it at the LOC. Nice not dealing with the collar at all... like anything else, just takes a bit of practice. Like sharpening freehand on a stone, I can tell if a knife needs a bit of adjusting in the belly/tip area, and can adjust accordingly. I liked how quick I could get thru the block of knives... just clamp and go. About as fast as freehand, with the benefit of a bit of a guide.
It's actually only 3 parts (2nd USB, 2nd Tool Support... basically a "Bench Grinder Mount" kit)... and the rod, (and a way to put it together... I used what I had avail.... hose clamps). (eBay can be your friend here). :)
Plus the tool test with mounting holes tapped into it, and the vertical usb and the laser mounted to that, and the digital angle finder....
Not that it's a big deal, or a bad thing, just made me chuckle a bit :)
I think I'm missing something here though.... How are you seeing the angle?
I get that the angle finder can easily adjust from your starting point, but how do you find what angle the wheel is hitting the blade when the blade is kept parallel to the table? This would change depending on the height of the usb, right?
Quote from: Kavik on August 30, 2017, 10:18:48 PM
Plus the tool test with mounting holes tapped into it, and the vertical usb and the laser mounted to that, and the digital angle finder....
Not that it's a big deal, or a bad thing, just made me chuckle a bit :)
I think I'm missing something here though.... How are you seeing the angle?
I get that the angle finder can easily adjust from your starting point, but how do you find what angle the wheel is hitting the blade when the blade is kept parallel to the table? This would change depending on the height of the usb, right?
Ah... good point... forgot about the tool rest. (I didn't tap it.. just drilled and bolt/nut combo). Digital angle finder... optional... although you would need some way to find level. (I have one from other stuff). I've also used a simple bubble level (as long as the machine is level which it usually is).
The angle is set based on the Laser Guided thread (https://forum.tormek.com/index.php?topic=3329.msg20333). You adjust the USB to set the knife parallel to the angle you want to sharpen at.
Really not as complicated as it's sounding... ::) Maybe when Tormek puts together a "Laser Guided Knife Sharpening Kit"... it'll be easier. ;D ;D
Aha! I knew I was missing something... Forgot to follow that link to the laser guided setup after finishing reading that post lol
I still gotta get around to ordering a laser line, but I'm thinking it'll be easy enough (and cheaper) to mount a rod through a hole drilled in the top of the machine. Not needing to buy another usb, and leaving both usb mounts free to use. Just as a thought :)
Thanks for sharing this idea!
Quote from: Kavik on August 30, 2017, 11:38:27 PM
Aha! I knew I was missing something... Forgot to follow that link to the laser guided setup after finishing reading that post lol
I still gotta get around to ordering a laser line, but I'm thinking it'll be easy enough (and cheaper) to mount a rod through a hole drilled in the top of the machine. Not needing to buy another usb, and leaving both usb mounts free to use. Just as a thought :)
Thanks for sharing this idea!
Thanks. No doubt there's better ways of mounting the laser... this just happened to be what I had. I do like taking it off though, or sometimes just pivoting it out of the way. Yours is a good idea... although you'll need a flat surface to stick the laser to (if you get a magnetic one). The USB I was using has a "flat side" (not all do), but even with that I ended up adding a wider flat piece of metal... worked a bit better.