I wanted a riving a knife for my draper table saw that would allow me to make cuts that were not full depth. Thought some people here might be interested in seeing the production process. Not quite finished yet but getting there.
Making a new riving knife.
- Thread starter Rorschach
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AES
Established Member
I'm not in the need of a riving knife myself Rorschach (I don't own a TS)!
But that looks like a nice job you've got underway there. Just as a matter of interest, I assume it's bog standard MS plate (?), but how thick please? And how are/will you go about shaping the big curved cut out?
And the straight cut you've already made at the bottom of pic 3 looks very "neat & tidy". How have you done that please?
But that looks like a nice job you've got underway there. Just as a matter of interest, I assume it's bog standard MS plate (?), but how thick please? And how are/will you go about shaping the big curved cut out?
And the straight cut you've already made at the bottom of pic 3 looks very "neat & tidy". How have you done that please?
ScaredyCat
Established Member
Are you willing to make more of these? 
.
.
AES":3hqqwbbe said:
It is 2.6mm steel plate (came from scrap so no idea what steel it is), the original riving knife was 2.6mm and I was lucky to get a suitable piece.
All the shaping was done freehand using a metal cutting bandsaw and then tidied up with files and the belt grinder. The curved cut was done on the bandsaw but as you can see in one of the pics I made a series of relief cuts to help me cut as close to the curve as possible.
AES
Established Member
Thanks, I wondered about those relief cuts. Yup, 2.6mm is a bit of a "funny".
AES":3n8g6jav said:
The relief cuts really help. I was able to cut right up to the line and it only took a few minutes with a files to tidy it up the curve.
I was lucky to stumble on the plate. If I hadn't managed to get something the right size though I would have just bought some 2.5mm plate, I doubt it would have made any difference and there is some adjustment in the mounting anyway.
ScaredyCat":2s81h6zp said:Are you willing to make more of these?
I guess I could, but there is a good bit of work involved, I am not sure how economically viable it would be. Guess it depends how much draper would charge for another riving knife to modify and how much you want one :lol:
Steve Maskery
Established Member
Nice job, R.
I've been down this road myself, so can I chip my 2p?
I used gauge plate for mine, not so that I could harden it, but more in the hope that it would stay flat.
The problem with Mild Steel is that it is so very easy to bend it when you are cutting it, and a RK that is bent is useless, and, dare I say it, probably more dangerous than not using one at all (that is not an encouragement to use TS without one!). It has to be flat.
(I did film the making of one when I did my TS DVDs, but there was a fault with the camera, the footage was unusable and I had to be out by next week, so no time to re-do it. Maybe I should revisit the subject.)
It's not that you can't accidentally bend gauge plate, but I do think it is more suitable than ordinary MS.
I'm still using that same RK today. I can cut rebates, for example, without removing it completely, and because I don't rely on the RK to mount the guard, I can do non-standard cuts like that without exposing myself to a naked blade.
I would rec that anyone who wants to do this sort of thing to take great care to ensure that the RK is flat (so that you don't have fight when the workpiece reaches the RK) and that you fit an overhead guard which gives at least as much protection as the original RK-mounted guard did.
Best wishes, decadigit Steve.
I've been down this road myself, so can I chip my 2p?
I used gauge plate for mine, not so that I could harden it, but more in the hope that it would stay flat.
The problem with Mild Steel is that it is so very easy to bend it when you are cutting it, and a RK that is bent is useless, and, dare I say it, probably more dangerous than not using one at all (that is not an encouragement to use TS without one!). It has to be flat.
(I did film the making of one when I did my TS DVDs, but there was a fault with the camera, the footage was unusable and I had to be out by next week, so no time to re-do it. Maybe I should revisit the subject.)
It's not that you can't accidentally bend gauge plate, but I do think it is more suitable than ordinary MS.
I'm still using that same RK today. I can cut rebates, for example, without removing it completely, and because I don't rely on the RK to mount the guard, I can do non-standard cuts like that without exposing myself to a naked blade.
I would rec that anyone who wants to do this sort of thing to take great care to ensure that the RK is flat (so that you don't have fight when the workpiece reaches the RK) and that you fit an overhead guard which gives at least as much protection as the original RK-mounted guard did.
Best wishes, decadigit Steve.
Thanks for the input there.
I was lucky, this plate was very flat and the cutting method I used was never going to cause any bending. When filing I made sure it will well choked up in the vice for support.
I am not sure if I will make an overhead guard. To be honest I expect to mostly be using the stand RK with the fitted guard, partly for safety but also for the vastly improved dust collection. I made this mostly because I just wanted the option of having this style should a project come up.
If I get round to fitting a router to the table saw wing, I might not ever need to use this RK but it's nice knowing it's there and it was fun to make.
I was lucky, this plate was very flat and the cutting method I used was never going to cause any bending. When filing I made sure it will well choked up in the vice for support.
I am not sure if I will make an overhead guard. To be honest I expect to mostly be using the stand RK with the fitted guard, partly for safety but also for the vastly improved dust collection. I made this mostly because I just wanted the option of having this style should a project come up.
If I get round to fitting a router to the table saw wing, I might not ever need to use this RK but it's nice knowing it's there and it was fun to make.
AES
Established Member
As said before, I know nothing about riving knives (I don't have a TS) but did know/understand that they need to be dead flat which is why I asked Rorschach my Qs.
I must say that from my experience of cutting metal generally, if anyone goes about the job as Rorschach has described you should not distort or bend the metal if using either mild steel or gauge plate. Mind you, I don't really know exactly what the forces are on an RK in use/mis-use!
I must say that from my experience of cutting metal generally, if anyone goes about the job as Rorschach has described you should not distort or bend the metal if using either mild steel or gauge plate. Mind you, I don't really know exactly what the forces are on an RK in use/mis-use!
user22161
Established Member
Nice job by the OP but I found it simpler to buy a second knife (saw still current) and cut it down with angle grinder.
user22161
Established Member
Rorschach":3hgas3m3 said:
Different saw, not Draper.
Rorschach":3g6mr5jr said:
I have a Draper PT and when I needed a new set of blades (long story, stupid blade sharpener, original blades knackered) I used this page on the Draper website to find a stockist near me who was able to order directly from Draper.
https://www.drapertools.com/stockist
will1983":2axcbc57 said:
Thanks, I'll try that in the future.
To be honest though, the time it would take me to contact a stockist, get the part (if possible) and pay for it, I am probably better off with what I did. Material was free, took less than 2 hours to make and it was enjoyable. Obviously I am lucky I had good tools to speed up the process. If I had to cut it out with a hacksaw maybe I would have tried harder to buy one :lol:
AES
Established Member
As already said, I think Rorschach has done an excellent job of making that RK. And without taking anything at all away from what he's done there, apart from having a metal-cutting band saw (which of course automatically supports the cut from under the cut, thereby ensuring no distortions of the finished article) there's nothing there that couldn't be done with normal metal cutting hand tools.
As remarked in my "Hacksaws & How to" in the "Metal Murdering" section here, I'm often quite surprised at the number of members here who obviously produce some wonderful "shapes" of great complexity in wood but seem to shy away from having a go at a quite simple metal equivalent.
OK, I have the advantage of having "enjoyed" a good apprenticeship which covered such stuff in detail, but with a hack saw and some files it's actually quite easy to produce a shape like that RK in sheet steel. A bit of practice and the right technique makes the job, IMO anyway, quite simple and also IMO, very satisfying (if not least because you've saved a few bob that can no go towards buying something that you really do need to buy)!
If anyone is tempted to have a go next time, the above blurb on hacksaws (and another on files and filing - same section here) is just one example of info freely available all over the place. And without blowing my own trumpet, both those blurbs were specifically aimed at folk with little metal working experience and a limited metals tool kit. Assuming you're not a wood professional, where time is money of course, my advice would be to have a go - another skill added to the armoury plus the satisfaction gained.
Well done Rorschach.
As remarked in my "Hacksaws & How to" in the "Metal Murdering" section here, I'm often quite surprised at the number of members here who obviously produce some wonderful "shapes" of great complexity in wood but seem to shy away from having a go at a quite simple metal equivalent.
OK, I have the advantage of having "enjoyed" a good apprenticeship which covered such stuff in detail, but with a hack saw and some files it's actually quite easy to produce a shape like that RK in sheet steel. A bit of practice and the right technique makes the job, IMO anyway, quite simple and also IMO, very satisfying (if not least because you've saved a few bob that can no go towards buying something that you really do need to buy)!
If anyone is tempted to have a go next time, the above blurb on hacksaws (and another on files and filing - same section here) is just one example of info freely available all over the place. And without blowing my own trumpet, both those blurbs were specifically aimed at folk with little metal working experience and a limited metals tool kit. Assuming you're not a wood professional, where time is money of course, my advice would be to have a go - another skill added to the armoury plus the satisfaction gained.
Well done Rorschach.
I have read your hacksawing tutorial and I recall finding it very useful. Didn't you also write one on filing too? I learnt a lot there and I am someone who uses files almost every day so you should never think you have mastered something and get complacent.
This is absolutely a job that could be done with a hacksaw and files alone, though I suspect it would take a good bit of time longer than using a bandsaw.
I mostly use a hacksaw in the workshop actually, I have an eclipse 18t and a 32t in dedicated frames as well as another frame with an old blade in it that I use for abrasive materials and other dirty jobs so I don't ruin a good eclipse blade. For most of what I do it is faster and better exercise to use a hacksaw than setup the bandsaw which is also very noisy and messier.
This is absolutely a job that could be done with a hacksaw and files alone, though I suspect it would take a good bit of time longer than using a bandsaw.
I mostly use a hacksaw in the workshop actually, I have an eclipse 18t and a 32t in dedicated frames as well as another frame with an old blade in it that I use for abrasive materials and other dirty jobs so I don't ruin a good eclipse blade. For most of what I do it is faster and better exercise to use a hacksaw than setup the bandsaw which is also very noisy and messier.
AES
Established Member
Thanks for the comments mate. Yup, I'm the guilty party for both the hack saws and filing blurbs. Glad you found them useful, though as said in my last post above here, they were aimed primarily at metal "newbees".
Yup, apart from the risk of distorting the job while initial cutting out by hand (support needed), IMO you're dead right, a hacksaw/s with 18, 24, and 32 TPI blades will cover a lot of work, including a relatively simple job like your RK. (And yeah, I must also plead guilty, I have FIVE - ! - hack saw frames always set up with 1 each 18, 24, and 32 TPI blades, plus another with a "funny abrafile/tungsten abrasive" blade in it for rough cutting really hard stuff, and another modified one with a 10 TPI machine hack saw blade in it). Agreed that that IS perhaps a bit OTT though!
My main hope though is to try and improve my own wood bashing (LOTS of help and inspiration to be found here) while at the same time, "pay back" a bit by helping others to have a go at metal murdering.
Edit for P.S. Yeah, I guess you're right, without your metal band saw I would think you'd need more than your couple of hours to finish your RK.
Yup, apart from the risk of distorting the job while initial cutting out by hand (support needed), IMO you're dead right, a hacksaw/s with 18, 24, and 32 TPI blades will cover a lot of work, including a relatively simple job like your RK. (And yeah, I must also plead guilty, I have FIVE - ! - hack saw frames always set up with 1 each 18, 24, and 32 TPI blades, plus another with a "funny abrafile/tungsten abrasive" blade in it for rough cutting really hard stuff, and another modified one with a 10 TPI machine hack saw blade in it). Agreed that that IS perhaps a bit OTT though!
My main hope though is to try and improve my own wood bashing (LOTS of help and inspiration to be found here) while at the same time, "pay back" a bit by helping others to have a go at metal murdering.
Edit for P.S. Yeah, I guess you're right, without your metal band saw I would think you'd need more than your couple of hours to finish your RK.
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