CS with Zero clearance insert, why it's chipping?

[Niki]

Good day

Today, I made Zero clearance inserts, but the cut (on Melamine) was not totally chip-free.

Is it like that also with the commercial ones or I have some basic mistake.

I'm using 72 T, 1.6 mm kerf blade.

Pictures removed, in any case it's not working...

Thanks
niki

 

[Paul Chapman]

Hi Niki,

Maybe the problem is with the tooth pattern on the blade - possibly a triple chip tooth pattern would produce better results in melamine coated boards?

Cheers :wink:

Paul

 

[Niki]

Thank you Paul

Ok, it's shopping time.
Now, how do you say in Polish Triple chip :lol:

niki

 

[JFC]

Triple chip is peir doller isnt it ? Thats what the polish lads tought me :lol:

 

[Niki]

You are almost correct JFC
Its called Pier dollishe.
Your advance in Polish is amazing. :lol: :lol: :lol:

niki

 

[Scrit]

Festool use a plastic (I suspect HDPE or nylon) insert at the leading edge of the blade for their anti-chip packing (the only place you actually need it). I suspect that your problem can be broken down into several component areas:

1. Blade run-out

2. Bearing quality

3. Blade rigidity - commecrial table saws use blades at least 3.2mm thick at tip (2.7/2.8mm thick body) which makes them less likely to "wow and flutter" (i.e. flex in cut)

4. You might achieve a better cut with your existing cut if you were to make the first cut at, say, a 1 mm depth pulling the saw backwards from the far end before making the cut at full depth. Dont't go deeper that 2 or 3 mm as there is a danger of climb cutting andalso the riving knife will get in the way. This would simulate the action of a scoring saw unit on a conventional static panel saw and is a technique adopted by Mafell on at least one of their range. It is particularly effective with triple chip blades. It's what I tend to do on my saw/rail system when I'm out on site

5. Blade sharpness - you may only achieve 20 to 40 metres cutting on a blade depending on make, grind, etc.

There is an alternative solution, although it must be used with caution because it increases the tendency to kickback - use a negative rake blade (normally sold as a mitre blade for the RAS or chop saw). This will tend to cause the work to climb the blade - a potential kickback hazard - but the cut will be remarkably good. Just use carefully and preferably with a hold down if used on the table saw!

Scrit

 

[Niki]

Thank you so much for your detailed explanation (as usual) Scrit.

Yes, the saw is very old and so is the blade not to mention the 1.6mm kerf that does not leave so much "meat" for the body.

This 20~40 meter cutting per blade is quit discouraging.

I will try the backward scoring and see what will be the result.

The negative rake blade sounds very promising, I have a front handle on the base (not shown on the picture) so I can press and hold it firmly to the work.

Many Thanks
niki

 

[Paul Chapman]

Hi again Niki,

Another option might be to use a router when cutting melamine-faced boards, the cutting action of which is less likely to cause the surface to chip out - it's what I do :wink:

Cheers

Paul

 

[Scrit]

This 20~40 meter cutting per blade is quit discouraging.

Well I reckon on getting 200 to 500 metres out of an industrial 12in blade (72t ATB) when used in conjunction with a scoring blade on a panel saw - thereafter it all starts to go off a bit and you start to get get chipping - it all depends on what the job calls for as you can frequently get away with a "good one side" approach, e.g. kitchen cabinets. The bigger the blade, the longer the life. A "bombastic grind" (one of those really aggressive angle grinds as proposed by Scheppach, Felder, et al seem to do only about 50 to 100 metres before degrading on a 12in blade - tried them but just couldn't live with the grinding costs.

As a point of comparison a TCT router cutter gives you just two or three worktop joints (circa 28 to 42 metres) before starting to show signs of degradation - hence kitchen fitters going over more and more to TC-RT tools

Scrit

 

[Lee Brubaker]

The blade I use has 80T & carries a label "specifically for melamine". I still get some chipping until recently when I started laying down a strip of masking tape on the cut line & sawing through it.

Lee

 

[dedee]

This seems like an ideal opportunity to use a saw board as you could run a sharp knife along the edge of the board prior to cutting. This will only give chip free edges on one side of the cut though.

Andy

 

[Paul Chapman]

Why I went over to using a router rather than a circular saw for cutting melamine-faced boards (and I'm only talking here of hobby use) was that the cuts were better and cheaper. I found that because a router cuts the board sideways rather than upwards, even when the cutter starts to degrade you can get good results from it for quite a while, whereas when a circular saw blade starts to degrade it will chip the surface every time. For melamine-faced boards I tend to use relatively cheap cutters and treat them as disposable - I usually keep my eyes open in places like B&Q and buy theirs cheap in sales.

Ideally, though, I don't use melamine-faced boards if I can help it - I hate the stuff :wink:

Cheers

Paul

 

[George_N]

My recent experience of cutting MFC, here, tells me that the damn stuff eats TCT saw blades and router cutters at an alarming rate. After two or three panels for a kitchen cabinet I start to see signs of chipping, even with a good quality triple chip blade. I might try Lee's tip of using masking tape on the cut line when doing show edges. I have done this in the past with a hand-held CS, with some success, any reason it wouldn't work on a table saw?

 

[Paul Chapman]

My recent experience of cutting MFC, here, tells me that the damn stuff eats TCT saw blades and router cutters at an alarming rate.

I've re-read your previous posts, George, and while it's difficult to be precise, from your description I reckon I'm getting more from my router bits than you are from yours. Do you take shallow or deep cuts? I usually cut the boards roughly to size freehand with a jigsaw (I score a line first with a Stanley knife and laminate blade), then I do the finish cut with a router (without scoring the surface) but in a series of very shallow cuts. I've found that expensive cutters, while worth the cost when cutting other materials, do not justify their high price when cutting MFC - they seem to blunt almost as quickly Incidentally, for this sort of work I use a half-inch router with half-inch diameter bit.

Cheers :wink:

Paul

 

[Scrit]

My recent experience of cutting MFC tells me that the damn stuff eats TCT saw blades and router cutters at an alarming rate. After two or three panels for a kitchen cabinet I start to see signs of chipping, even with a good quality triple chip blade.

Only that it will tend to get rubbed off as you push the material across the machine - and if it sticks it can be a pain to deal with (i.e tried it a long time back and gave up). If your blade is reasonably sharp you can fiddle with the sawblade height to get a better finish on the table saw. One point that Niki brought up was that his saw blade plate was just 1.8mm thick. Thin saw plates tend to vibrate more in cut and this "wow and flutter" contributes to chipping out on the top surface on a table saw, hence the normal advice to position the blade low in cut. I wonder how much difference adding blade stiffeners to the blade will make. Perhaps some of our American posters could contribute here.

You may like to know that almost every secondhand sliding table panel saw I've ever seen has nicks out of the blade edge of the sliding table - to get a 3mm deep cut in an edge requires a 4 to 5mm deflection of a 300mm blade, 2.8mm thick tempered steel plate supported in 50mm diameter washers - so 4 to 5mm over 125mm. These nicks are caused by people pushing material into a (blunt) blade too hard. So even trade users have problems with blade deflection on thicker blades.

Another thing to try is to use a negative rake blade (i.e. a mitre saw blade). This must be used with caution as it has a lot more cutting resistance and you do need to press hard down onto the material as you saw and work slowly to ensure the work doesn't climb the blade (table saw - a hand circular saw would try to climb the workpiece) and then kick back, but having been put onto this by another trade WWer and tried it in my flip-over saw, and found it works, I've taken to using this on installations where I need to trim MFC/MF-MDF filler strips.

Scrit

 

[Scrit]

I've found that expensive cutters, while worth the cost when cutting other materials, do not justify their high price when cutting MFC - they seem to blunt almost as quickly Incidentally, for this sort of work I use a half-inch router with half-inch diameter bit.

From experience of running CNC routers the larger the diameter of bit you can use with MFC the better because larger tool bodies have much better heat dissipation and that seems to make the edge last longer. In terms of tip durabilily I used to find disposable carbide tips to be sharper than brazed tips as well as holding their edge longer, especially the TiN-coated ones like the KWO Versofix sold by Wealden Tools. The other pluses are the tool remains constant diameter (much better if you do any amount of template routing - brazed tip tooling shrinks every time it is ground) and that you don't lose a tool for a week whilst it is sharpened.

Scrit

 

[Niki]

After a few more tests and re-thinking, I decided to leave the job for the Felder guys.
I don't know if you have such a system in UK, but here, I just order my dimensions and the next day I have it shipped to my house.
It costs me additional 2 Zloty ($0.6) per piece, so if I'm ordering, say, 28 pieces (for 7 cabinets) it will be additional 56 Zloty ($19), but I don't have to deal with big and heavy plates and the cuts are very accurate and smooth from both sides, not to mention the free delivery.
That way, it will cost me much less than saw blades or router bits, I think.

niki

 

[George_N]

My recent experience of cutting MFC, here, tells me that the damn stuff eats TCT saw blades and router cutters at an alarming rate.

I've re-read your previous posts, George, and while it's difficult to be precise, from your description I reckon I'm getting more from my router bits than you are from yours. Do you take shallow or deep cuts? I usually cut the boards roughly to size freehand with a jigsaw (I score a line first with a Stanley knife and laminate blade), then I do the finish cut with a router (without scoring the surface) but in a series of very shallow cuts. I've found that expensive cutters, while worth the cost when cutting other materials, do not justify their high price when cutting MFC - they seem to blunt almost as quickly Incidentally, for this sort of work I use a half-inch router with half-inch diameter bit.

Cheers :wink:

Paul

Paul,
I have mostly been cutting housings/dados in cabinet sides to fit full thickness backs. The batch of MFC I have is 18.6 mm thick so I have been using 19 mm dia. bits. Because the housings are only a few mm deep, and need to be a consistent depth, it is always the same part of the cutting edge that is going through the laminate. If I use the router table to dress cut edges it is better, in that I can move the bit up or down to use a fresh part of the cutter. I agree that good quality bits (Wealden) don't last any longer than cheap ones (B&Q) for this job. I have just bought a 19 mm hinge mortising bit to try on the housings...it may not last any longer than a regular straight bit but it is a little cheaper and I can still buy several of them for the price of one replaceable tip cutter.

 

[Paul Chapman]

From experience of running CNC routers the larger the diameter of bit you can use with MFC the better because larger tool bodies have much better heat dissipation and that seems to make the edge last longer.

Thanks, Scrit, that's helpful to know. It was always my gut feeling that larger diameter bits lasted longer, but as I only do a fraction of the routing you do I wasn't sure whether it was true or all my imagination

Thanks :wink:

Paul

 

[Scrit]

I have just bought a 19 mm hinge mortising bit to try on the housings...it may not last any longer than a regular straight bit but it is a little cheaper and I can still buy several of them for the price of one replaceable tip cutter.

I pay just under £ 5.70 per (reversible) tip and the 18mm body with a tip installed costs circa £39. From experience the tips outlast brazed carbide by about 50% and they are reversible, so for £ 5.70 I'm getting the equivalent of 3 cheap TCT router cutters, at say £5.00 each for the brazed TCT? As the tool body costs £33 (in effect) and will do hundreds of tips before wear becomes apparent I'm up on the deal somewhere around TCT cutter #12 (or tip #4), thereafter the cost of running the TC-RT drops. So I think that your maths is out. If you only use a few TCT cutters a year probably not worth it - as soon as you need to use more than 4 or 5 a year then TC-RT makes perfect sense. And as I said - kitchen fitters use the TC-RTs a lot these days because they are sharper and cut cleaner for longer with less chipping out - so better qualiity and cheaper in the long run, too.

Scrit