Thread: Can I add extra bearings to a pattern router bit ?

The line and arrow indicates the recommended distance the shaft should be in the collet to be held securely. This absolutely rules out 3 bearings, you might get 2.

Why not just get a longer pattern bit?

Could you now clean out the rest with a chisel.
Now that you have created walls to guide your chisel.

Cheers Matt


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Looks tom me that you have space for a bearing. If you can get a beating give it a go. Bearings that size are generally cheap

If you used a copy ring on the router you could make the template much thinner and not be limited so much by the length of cutter/bearing.

I don't think that there is enough shaft available for an extra 10mm of bearing and the collet nut.
You can add another bearing but if you have the cutter protruding from the collet past the mark it may work loose with disastrous consequences for the job and possibly you. I don't think that there is enough shaft available for an extra 10mm of bearing and the collet nut.

The main problem with bearing based copy cutters is that they are not really designed to be used for deep routing as you need to have a deep template so that you can route in stages.

What's wrong with doing away with the template and use the sides of the cutout. If that's not possible, make a new guide 10 mm lower.
The line and arrow would be for maximum that the cutter can come out, any more, it could start to vibrate and give a terrible cut. DAMHIKT
Have had a cutter come loose.
Kryn

Originally Posted by elanjacobs

The line and arrow indicates the recommended distance the shaft should be in the collet to be held securely. This absolutely rules out 3 bearings, you might get 2.

Why not just get a longer pattern bit?

But Elan, the shaft is 65mm long above the bearings . The shaft usually goes into a collet 19mm . There's a lot of the shaft left , around 45mm, after putting the shaft into the collet and backing it off a couple of mm.

Originally Posted by KBs PensNmore

What's wrong with doing away with the template and use the sides of the cutout. If that's not possible, make a new guide 10 mm lower.
The line and arrow would be for maximum that the cutter can come out, any more, it could start to vibrate and give a terrible cut. DAMHIKT
Have had a cutter come loose.
Kryn

Thanks Kyrn, but the bottom of the rout is angled at 2.3 degrees, so I have to use the rails of the jig which are set at that angle for the router base to rest on.

Re the line on the 8mm shaft, please read my reply to elan just above. But I may be misunderstanding something here.... ?

19mm is the absolute minimum, but it's good practice to have it in further where possible.

Originally Posted by Bohdan

If you used a copy ring on the router you could make the template much thinner and not be limited so much by the length of cutter/bearing.

I don't think that there is enough shaft available for an extra 10mm of bearing and the collet nut.
You can add another bearing but if you have the cutter protruding from the collet past the mark it may work loose with disastrous consequences for the job and possibly you. I don't think that there is enough shaft available for an extra 10mm of bearing and the collet nut.

The main problem with bearing based copy cutters is that they are not really designed to be used for deep routing as you need to have a deep template so that you can route in stages.

The item T8056B-8 on the link below to the catalogue page is the 8mm bit I have bought with the extra long shaft, to give me the depth I want. The line on the shaft is about 10mm above the top of the bearings. I can only push the shaft into the collet about 19mm.

https://www.wealdentool.com/cgi-bin/...ml#aT8056B_2d8

For doing deep mortising work like this you're much better to be using template guides and solid carbide upcut spiral router bits. Sorry that doesn't help with your current predicament, but a very worthwhile investment if you're expecting to be doing more of this type of work.

Could you change the thickness of the rail guides? Put them through a thicknesser to take some height off them but not too much so they don't flex with the router on them?? Or create wedges at the correct angle so you don't have the guides suspended over the work piece?? Just ideas...


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Originally Posted by aldav

For doing deep mortising work like this you're much better to be using template guides and solid carbide upcut spiral router bits. Sorry that doesn't help with your current predicament, but a very worthwhile investment if you're expecting to be doing more of this type of work.

I'm pretty much snookered here with the bit. I don't want to shift the jig, in any way as its been set up precisely for squareness for the neck relative to the body, and also neck rake angle, which is determined by a number of factors.

I had another look at the jig , and I could use slow cure super glue to affix 2 pieces of 20mm x 20mm x 60 mm long dressed pine up under the rails, moving it into position until it lines up exactly with the face of the laminex strips (inside the rails) that my previous bit's bearing rode on . Then secure each of these square pieces in place with 2 x countersink screws down through the rails.

Just to clarify, my initial concern when I received the bit in the mail today was how I was going to make a dead square entry cut to the sides of the open end of the pocket without the top bearing contacting anything but air, before it picked up the side walls already routed.

This bit is supposed to be meant for deep and relatively narrow pocket routing, hence its 8mm shaft not 6mm. And an overall length of 74mm from top of bearing to the end of the shaft.

Some of the posts here are making me think it may not do the job safely regardless. Ive only got 6mm cut depth or so to go..... and still to use the new bit.

I have considered leaving say, 2 -3mm of side clearance at the edges of the pocket, and then carefully move the bit across until the bearing contacts the already routed walls. Finish the job by removing the resultant ridges later with hand tools once the body is out of the jig.

Being relatively new to routing, I am a bit concerned (no pun intended) that the router might move under its own steam just before it contacts the guide surface of the already routed walls, and make a very bad looking neck to body join, in a very obvious place !

Originally Posted by donnyb

I can only push the shaft into the collet about 19mm.

This would suggest that the long cutter is probably suitable for what you want to do as it will run on the wall of the material that you have already routed.

As the cutter will only go into the collet about 19mm you should be fine as long as you push the cutter fully into the collet. Just one warning Do not bottom the cutter in the collet.

Leave it a mm off the bottom, if you don't when you try to remove the cutter it may jamb and not loosen easily.

Originally Posted by Bohdan

This would suggest that the long cutter is probably suitable for what you want to do as it will run on the wall of the material that you have already routed.

As the cutter will only go into the collet about 19mm you should be fine as long as you push the cutter fully into the collet. Just one warning Do not bottom the cutter in the collet.

Originally Posted by Bohdan

Leave it a mm off the bottom, if you don't when you try to remove the cutter it may jamb and not loosen easily.

Bohdan, I went out this morning and measured20170214_070709.jpg how far the shaft goes into the new 8mm collet. Its bottoms out at 30mm, not 19mm. My error . Nevertheless, after providing a mm clearance off the bottom, it still leaves that line and arrow on the shaft 25 -27mm below the outer face of the collet , which does still allow the cutting flutes to do the rest of the rout.

So, I'm still puzzled what the line and arrow indicates, as I had realised that on other bits Ive used, its a maximum 'out of the collet' mark. Maybe its a manufacturing mass production marking glitch. Ive emailed the supplier in the UK to check.

Any comment on gluing and then screwing 20x20 x 60 mm guide pieces up under the jig rails to give the bearing a pocket side entry support ?