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By Honest John
#1166876
After reading a post recently in which Sunny Bob admitted to the world that he had bought and used a microjig 3D push block thingy at vast expense, but that he thought it was worth it to maintain a full compliment of digits. Now being a tool tart and a pushover to sell tools to, I investigated these devices, liked what I saw and bought one. I like it a lot, and it will get a good deal of use on table saw, router table and bandsaw. This was the point that I thought I really could do to make a zero clearance insert for my saw. On examining the original, it's in 2 separate pieces, mitre side plastic and fence side aluminium. No problem with that I could make a single one for regular cuts, and revert to the original equipment for the rare occasions I make mitre cuts. The supporting lugs on the Axminster saw are only about 3.2mm below the table surface so there isn't a lot to support my shop made insert. I have used an offcut of a laminate floor board, cut to size and then rebated on my router table to make it flush with the table surface. After raising the blade through it and extending the cut to allow for the rising knife it actually has worked out rather well. However, I do worry a little that it only sits on about 3mm of a resin/mdf type material. The TS250 is a common enough saw, has anybody found a better workaround to this shallow mountingplate?
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By Eric The Viking
#1166942
I'm going to have a similar problem when I get my TS 200 back on the road (Mk1 - really old!).

You might have enough space behind the RK to glue a strengthening piece across the underside of the insert. And for the front do something similar with a horizontal U-shape that sticks out under the tabletop (thus supporting both sides, but not in the way of the blade). That would avoid modding the cast iron.

You might also be able to make the ZCI from something stronger instead, such as aluminium (I'm considering that for mine).

Marcros's idea works well too - there are several people on here who did that with their TS 200s (before the TS 250 came out).

HTH, E. (I'll be watching this thread for ideas!)

(edited to correct something)
Last edited by Eric The Viking on 16 Aug 2017, 17:20, edited 2 times in total.
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By Honest John
#1167204
IMG_0316.jpg

as can be seen (I hope) the support for the insert is only just over 3mm below the table surface. there is some scope for fixing something on the underside of this ledge and sticking out beyond support a deeper stronger insert on the right hand side. There is little scope for this on the mitre tilting side, or indeed at each end of the blade.
IMG_0316.jpg

My completed insert seems to work well and is firmer than I expected. I think perhaps I was worrying about nothing? Another thought I have had is to bolt a hardwood replaceable and sacrificial insert to the underside of the aluminium standard insert and fit it full width so to speak. The mitre side would have to be rabbeted to about 3mm of course, but this would be close to the blade and well supported by the solid fixing from the aluminium side. the aluminium original insert is about 5-6 mm from the blade, so the wooden insert addition would make a significant difference. As I have said my first attempted insert is working well and I have fitted a rabbeted piece of softwood to the underside to hook under the table throat edge, and just used a couple of fixing screws on the mitre side, so removal is quick and simple. This is the first time I have managed to post pictures and I have had to resort to my windows PC ( still cant send from my iPad)
IMG_0319.jpg
Attachments
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By Honest John
#1169289
I bought some jig making hardware from a local supplier I had not used before, quite recently, and I noticed on looking at his other items for sale, that he had some useful sizes of aluminium for sale in a variety of thicknesses. It crossed my mind that I could fashion a blank to fit my table saw throat from aluminium, perhaps backed with hardwood to improve rigidity. If I was to persue this line of production, what would be the best way to cut the slot. Specifically can the sawblade be raised through 3mm aluminium safely and without damage to the carbide tips? I am completely happy with the performance of my zero plate in my photos, but at some future date I wouldn't mind investigating the manufacture of an aluminium one. I could of course engineer a wider slot in an aluminium plate and infil the slot with harwood, and then raise the blade through this? Just thinking aloud. So I guess the gist of my enquiry is, can you raise the blade through an aluminium plate ?
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By Eric The Viking
#1169315
Lots of people do that (raise blade through aluminium plate). I intend to do just that myself.

It occurs to me, incidentally, that I might be able to flip the plate over the long axis too, to cut the extra part for the riving knife more easily. It depends on having the mitre slots and the blade opening parallel though, and I haven't checked that yet.

There's really only value in having the zero clearance at the front of the blade. It doesn't matter at the back where the teeth rise. I have bigger issues presently though, such as fixing the rise-fall pivot and attaching the new fence system, so I won't get there for a while yet.
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By Steve Maskery
#1169555
Personally I prefer plywood ZCIs. Admittedly I have more than 3mm or recess, but, IIRC, it is not much more than 3mm.
The point is that ZCIs wear, and it is easier and cheaper to pop in a new ply ZCI than an ali one.
Not only do they wear, but they only stay ZC at the front as long as the blade is only ever raised. As soon as you lower the blade a bit, although it might well be ZC at the sides, still, it is no longer ZC at the very front, and that can matter, especially if the workpiece has a fragile surface, such as a brittle veneer or melamine, for example.
This all reminds me that I need to make some new ZCIs for my own saw, I used my last one recently.
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By Eric The Viking
#1169581
Steve Maskery wrote:Personally I prefer plywood ZCIs. Admittedly I have more than 3mm or recess, but, IIRC, it is not much more than 3mm.
The point is that ZCIs wear, and it is easier and cheaper to pop in a new ply ZCI than an ali one.
Not only do they wear, but they only stay ZC at the front as long as the blade is only ever raised. As soon as you lower the blade a bit, although it might well be ZC at the sides, still, it is no longer ZC at the very front, and that can matter, especially if the workpiece has a fragile surface, such as a brittle veneer or melamine, for example.
This all reminds me that I need to make some new ZCIs for my own saw, I used my last one recently.


ISWYM, that's a good point.

And possibly an argument for some sort of sacrifical sled perhaps, so you can cut a fresh notch each time. I have to make a complete throat plate anyway (because I haven't got one with the saw), so it won't last as a ZCI. But It ought to be a handy template when I've done it!

And there's only 3-4mm of depth for anything around the RHS of the throat. I could go to any depth on the LHS of the blade, as presently there is no lip at all, but the issue with that is having the two sides different. It's probably easier to add matching support and not have to make a complex plate.

I shall apply more thought to it...

E.
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By MikeJhn
#1194878
Just thought I wold post a bit more information on this thread, the cast iron saw table top was recessed with a file to allow the magnet to sit a bit lower than the 3mm recess for the ZCI, the recess does not have to be that precise as the neodymium magnets are very tenacious and can cope with a bit of slack which makes the whole process easier.

Mike

ZCI magnets.jpg