Metric bits

[waynelocke]

I couldn't find it with a search but am pretty sure that the topic has come up before. Where can I find a metric bit with a 1/4" shank? I would like to cut some biscuit slots in some panels. The slots are 3mm, I think, so, specically, does anyone know who has a 3mm bit with a 1/4" shank?
Wayne Locke

[mikejohn]

Wayne
I doubt this helps you, but Trend C001A (solid Carbide) two flute straight cutter is a 1/4", 3mm cutting bit.
Their horizontal biscuit cutters, however, are 4mm.
The Trend C002 (solid Carbide) two flute straight cutter is a 1/4", 4mm cutting bit.
I guess this shows that they are out there.
www.trendmachinery.co.uk (http://www.trendmachinery.co.uk)

..........Mike

[terryd]

Wayne,

I use a company called Dimar, Bit # SCR4-3M which is a solid carbide 3mm bit with a 1/4" shank and a cutting depth of 11mm. They run me $24. each'
www.dimarcanada.com (http://www.dimarcanada.com) Phone 1-905-738-7919 Fax 1-905-738-3933

Terry

[supertigre]

Try a 5/32" bit. You'll like the result. AMHIK :o)

[mikejohn]

Guy
This appears to give a tight 4mm slot (3.92mm).
Are the biscuits Wayne wants to use 4mm?
Are all biscuits 4mm? I have never used them.

..............Mike

[waynelocke]

Mike,
You were right earlier. They are all 4mm.
Wayne

[supertigre]

Mike;

Yes 5/32 is .003" smaller than 4mm but I find the biscuits fit perfectly (freud and lamelo).

[waynelocke]

Guy,
I intend to order a 5/32 bit. It is reassuring to know someone else has done this.
Wayne

[mikejohn]

Guy,
The reason I asked about the sizes is, if the 5/32" gives a nice fit, then using a 'horizontal' 4mm bit is going to give you a very slack biscuit groove, if the z axis is even a fraction off vertical.
I was thinking of using the 'horizontal' method, maybe I will think again
.

............Mike

[bleeth]

The holding power of a biscuit comes from two things. The glue surface and the expansion of the biscuit when it gets wet from the glue. If a biscuit fits too tight to start with then the amount of adhesive that can migrate to the surface of the biscuit is reduced, which will result in a weakened joint. A proper fit is one in which you can insert the biscuit into the slot by hand without too much force. If your biscuits take too much effort to insert into the slot you can attribute that to moisture absorbtion from the environment, in which case they should be discarded or dried out (I have been told that a microwave will do the trick although I have never used this) or a too narrow slot. Different suppliers have different levels of quality control. For example, when PC introduced their slot cutter and biscuits, they were sufficiently thicker than true Lamello biscuits to require the PC blade to be ground down to use Lamello biscuits. Although this is no longer the case, it is a good example of minor tolerance issues affecting the results.
To use my cnc for alignment and assembly machining I prefer to use dowels, dados, or rabbets. For hand work I will use biscuits.

Dave

[supertigre]

Mike;

If you know of a joint or wood working process (other than pencils, matchsticks and toothpicks) that requires an accurcy of .003" I would love to hear about it, and then I would politely suggest that you are using the wrong material. If you breath on wood it can change more than .003" / 1".

Dave;

Several of my customers also use dowels/dados in the cabnitry that I cut for them. Biscuits work for me.

[bleeth]

Guy: I have no problems with biscuits either. It is simply the bit changing routine on a typical shop-bot that limits the amount of panel processing to be done economically on the machine. If I use a 3/8 or 1/2" bit for cutting then do my line, hinge, and drawer boring,and put in biscuits I have two tool changes. If I stick to the 3/8 I can do cutting and dowels but then have to use another tool for the dowels in the tops and bottoms. For dados I get all cutting and assembly machining as long as I don't use a 1/4" back from either bit as well as one-pass machining. If I really did use my bot for much cabinet production (at the moment it is a stock PRT although I'm working on that) I would add the air drill for boring.

Dave.

PS: Back not so long ago when the add on options to a bot were more limited it was pretty safe to discuss parameters of machining without knowing the now all-important information; what kind and size of bot and what options are on it.

[mikejohn]

Guy
What I was suggesting is an 'off axis' horizontal bit might give you a much wider 'kerf' than 4mm. The diameter of the bit is around 40mm (1.6")
This is not so much a problem with a 'normal' 4mm straight cutter.

.............Mike