Converting rip cut saw to cross cut
- This topic has 10 replies, 5 voices, and was last updated 1 year, 4 months ago by
.
-
Posts
-
Hello. I was wondering if it is a correct practice to reshape the teeth on a rip cut panel saw into cross cut pattern or should I remove the teeth completely and start from scratch.
Thanks!
You may consider this: if it’s an old saw there may be an element of work-hardening on teeth that haven’t been used in decades, but it’s not necessary unless the teeth are missing or are irregular or misshaped. It doesn’t matter if they are blunt at this point – just concentrate on looking at the shape and that the metal’s in good condition.
You don’t say what the size are (TPI) so we must assume that they are less than about 8 TPI. I personally wouldn’t bother filing a cross-cut on 10 teeth or smaller – it ain’t worth it.
From this point onward, it’s worth doing the job in logical steps.
I’d recommend tapping the set flat to remove any irregularity. Ensure that the teeth are flat by jointing with a file the full length until you have a clean set of tips.
Adjust the rake of the teeth first and get the teeth all level and get the shape right. Do this is if it is a Rip pattern. Next, at this point adjust your new set, alternate teeth, along the full length.
Decide all your angles and make any angle-jigs; carefully sharpen alternate teeth in the cross-cut pattern and repeat on the other side.Hope that it works and good luck……………..
Thank you @YrHenSaer for your recommendation. I’ll get to work and post my results. The saw is 7 TPI — don’t know why I didn’t mention it.
I have a related question. I currently have three 26” 8 TPI Disston rip saws; a D8, and two K3’s. The D8 has a pretty thick plate, one of the K3’s has a slightly thinner plate, and the other K3 has a pretty thin plate. I don’t see the need for three rip saws, so I’d like to convert one to a crosscut saw. Which one do you suggest I convert, and why?
On the basis that a wider plate would accept and maximise the fleam angles from your file better than a thin one – i.e. more meat for the file – I’d go for the thickest plate.
Otherwise it’s down to preference; six-of-one-and-half-a-dozen-of-the-other.If they are old plates, beware of work-hardening when re-setting the teeth. There’s no reason for it to happen and is totally unpredictable, but it has happened to me and there’s only one cure for a busted-off tooth.
Good luck.
Because of the rake angle and the clearance angle being 60 degrees apart you may have some difficulty going rip to cross cut.
Let’s say the saw is in the vise with the handle to the right and that the rake angle is 5 degrees – the cutting face of the teeth lean to the right 5 degrees from vertical. The back sides of the teeth will be 55 degrees off vertical because the files are 3 sided equilateral triangles.
Now to make cross cut teeth with 25 degree rake. From where the file sits in the rip tooth it will need to rotate 20 degrees clockwise. It will have to also change its angle to the toothline for fleam but let’s leave that out for this.
If the gullet stays in place, which makes keeping the pitch easier, the file won’t be contacting the back sides of the adjacent tooth because it’s at 55 off vertical and the new tooth form has the back side of the teeth at 35 off vertical, which is steeper.
The conversion will probably require either removing (jointing) most of the tooth so when the file reaches the gullet depth it makes full contact with the front and back of a tooth OR having a second gullet in each tooth which will look awful and be very difficult to maintain pitch with.
Converting in the other direction would be much easier.
Cunha, thanks. I hadn’t considered that aspect of the conversion. I have rewatched Paul’s YouTube video (https://youtu.be/_fNosQU1Ujg) on sharpening a crosscut saw, where he does actually discuss the requirement for a crosscut saw, and have decided that I may not need one after all. I have a brass back saw with crosscut teeth, and a circular saw for rough stock, and that takes care of most of my needs. When I need to cross cut material in my workshop, I’ll just use the thinner plate K3 for the sake of a smaller kerf. I am going to check the set, though, reduce that of the thinner plate saw, and increase that of the thicker D8 for the sake of speed when necessary.
My only cross-cut saw is the dreaded induction-hardened box store model that I use to break down big boards. Other than that I use rip saws for everything. A little slower but seems to work fine.
Crosscut saws seem to be more common so converting a scarcer saw (rip) to crosscut may not make a ton of sense considering the cost of a used crosscut. Also, rip saws tend to be larger teeth so the pitch may not make sense for normal thickness (3/4″) boards.
Having more than one saw makes sense if the pitch, set, and angles suit different materials and thicknesses. That is up to the user/sharpener to tailor the tools to the tasks at hand. For instance, I inherited a 4tpi rip which is great for ripping to width but I wouldn’t use it to cut a large tenon. Having a 7tpi works for that. It’s slower but easier to control.
I also have a cordless 6-1/2″ saw for when I’m not feeling like a zealot.
Because of the rake angle and the clearance angle being 60 degrees apart you may have some difficulty going rip to cross cut.
Let’s say the saw is in the vise with the handle to the right and that the rake angle is 5 degrees – the cutting face of the teeth lean to the right 5 degrees from vertical. The back sides of the teeth will be 55 degrees off vertical because the files are 3 sided equilateral triangles.
Now to make cross cut teeth with 25 degree rake. From where the file sits in the rip tooth it will need to rotate 20 degrees clockwise. It will have to also change its angle to the toothline for fleam but let’s leave that out for this.
If the gullet stays in place, which makes keeping the pitch easier, the file won’t be contacting the back sides of the adjacent tooth because it’s at 55 off vertical and the new tooth form has the back side of the teeth at 35 off vertical, which is steeper.
The conversion will probably require either removing (jointing) most of the tooth so when the file reaches the gullet depth it makes full contact with the front and back of a tooth OR having a second gullet in each tooth which will look awful and be very difficult to maintain pitch with.
Converting in the other direction would be much easier.
I found out this the hard way (by making the “mistake” I mean). I actually thought that I had executed wrongly the procedure but your explanation fits what happened to the saw’s toothline — it does look terrible. I kinda works but not very good I think.
I commend your explanation. I took me a while to fully understand it (and I had to re-read it with my saw and file on hand) but then it was an eye opener. Thanks a lot for your input.
I have an update:
Please note that this is a discussion of hand saws. I notice a reply regarding hand held circular saws. And of course it makes no sense to refile those.
I also note a reply which may be confusing thickness with width. Perhaps I used the wrong word, and when I said ‘width’, I should have said ‘height’. I mean the measurement from the teeth to the back, or spine of the plate.
After much to-and-froing, I refiled the middle thickness saw to a crosscut saw, and gave it a moderate set. I’m very happy I did. It’s nice to be able to get a faster, and better quality cut when desired. Much less work on the shooting board.
I also reset the thicker plate saw to the maximum I could. That was very interesting. I dialed the saw set to the maximum it would go, but because of the size of the teeth (8 TPI), they would only bend so far. I’m working with reclaimed fence, and deck material, so now I’m on the lookout for something with bigger teeth for ripping those 13-foot boards 😉
I left the thinnest saw as a rip, and its set it for the minimum kerf without binding too much. I’m cutting some larger tenons at the moment, and it’s nice to get close to the line with a decent finish.
- You must be logged in to reply to this topic.