# router cutter adaptor for spindle moulder



## gasman (2 Sep 2007)

Has anyone any experience of using half inch router cutter bits in a spindle moulder? I have a Record C26+ combination machine (which is great) and would like to be able to use router bits with it too. Axminster sell this http://www.axminster.co.uk/product.asp?pf_id=554588&name=796122+&user_search=1&sfile=1&jump=0
and I wondered if anyone has used it or anything like it?
Thanks for the advice


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## jasonB (2 Sep 2007)

You really need a spindle with adjustable speeds as a single speed will only be at optimum rpm when using large diameter cutters. The more expensive spindle moulders use a replacement spindle that has the end machines to take router cutters, maybe Scrit or Felderman can comment.

You will also need a spindle that drops at least 50mm below the table or have to pack the table up as the collet/bit will all be on the end of your spindle.

Jason


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## Scrit (2 Sep 2007)

The main problem I can see is that the C26 has two spindle speeds of 4,000 and 6,500 rpm respectively. These speeds are simply too slow for a router cutter and are designed with conventional spindle moulder cutterblocks in mind. To begin using a spindle with router tooling you ideally need a machine capable of 12,000 to 15,000 rpm (like the Felder) as even 10,000 can reduce the feed rate to a crawl and can result in poor quality of cut.

To demonstrate the point:

A 100mm 2-flute spindle moulder cutterblock is run at 6,500 rpm. This gives it a peripheral speed of approximately 2040 m/min and with a feed speed of 6 metres/min will give 2.166 cuts/mm (or a cut pitch of 0.46mm). That is a very acceptable feed speed and surface quality for most purposes and the peripheral speed is high enough to ensure good severing of wood fibres.

A 25mm 2-flute router cutter is run at the same speed. It gives a peripheral speed of approximately 510 m/min and the same number of cuts per inch as the spindle moulder block above. The difference is that the peripheral speed is too low to cut cleanly. Ideally we aim for at least 1250 to 1500 m/min peripheral speed on cutter blocks to ensure clean severing of fibres. The same 25mm router cutter run in a router at 18,000 rpm would yield a peripheral speed of 1414 m/min.

So the problem of running a router cutter in a spindle moulder is that the rotation speed is just too low in most cases to ensure a good quality of cut.

For the mathematically inclined the calculations are as follows:

Peripheral speed = Pi (22/7) x Diameter of cutter (in metres) * Spindle revs/min

Cuts per mm = (No. of cutter flutes x Spindle revs/min) / Feed rate in m/min 

Cut pitch (mm per cut) = 1 / Cuts per mm

Hand feed work can often be done at between 2 and 6 metres/min on the spindle moulder with similar feed rates achievable on the router

Scrit


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## woodbloke (2 Sep 2007)

Scrit is quite correct. Reference to Hayward's 'The Woodworker' Pocket Book' ( a wonderful little book if you can find a copy) from 1972 refers to the peripheral speed of a tooth (or blade I assume) which in *theory* should be in _'the region of 3000m per minute'_ so that the smaller diameter of the cutter or saw the faster it has to rotate to cut efficiently. In practical terms, Hayward's figure is probably too high and Scrits is much nearer the mark....just think of a single saw tooth travelling at about a mile a minute..... or slightly faster :shock: and you won't be far off - Rob


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