Surfacing bit question (safety)

SteveF

I picked up a surfacing bit from Wealden to use for thicknessing blanks.  It has quite a long 1/2” shaft and it can’t be inserted into the collet of my router as deep as the K mark.  Is this safe to use? (It will be in a router sled) I read about putting a bit all the way in and then backing it out slightly so it isn’t bottomed out in the collet, but perhaps I’ve picked up the wrong type of bit? 

Sporky

I have one of those - I only use it in the CNC machine.

I think if the shank is all the way into the collet (backed out a millimetre or so is often mentioned) it'll be ok, but it's a huge thing; take only very, very shallow passes at low RPM. The cutting faces will be moving very fast indeed.

SteveF

Thanks Sporky, I will give it a try.  It should be pretty stable and secure in The Beast, but I will take it steady and keep checking it's secure for the first bunch of passes.  I have a smaller bit for things like the headstock and fingerboard but thought the big yin might make blanks a little easier if they're not quite the right thickness when I buy them.

Sporky

Ah - that's much more substantial than I'd imagined from "router sled" - looks like a very nicely made tool.

I mostly use my one of those bits for flattening really curly interlocked grain that the thicknesser just tears out. For reducing the thickness by more than a couple of millimetres I have a smaller diameter bit that can go a bit deeper at a time. I may be over-cautious though.

SteveF

Thank you. I do have a smaller one that worked ok for thicknessing the headstock etc that was made from a couple of pieces of angle aluminium, but it's too small for body blanks.  I saw a bunch of these on Youtube and figured why not.  The cradle might need a V2 at some stage using ply rather than MDF but it should be big enough to handle anything I am likely to throw at it.

TTony

That looks far more substantial than my old thing!

Where did you source the rails, and the bits that they run through?

SteveF

16mm linear rails, bearing blocks and end stops. You can get them from Amazon or eBay under various brand names but I think they are the same.  I had to do a bit of hunting about to find the lengths I wanted at a decent price ended up with eBay I think 

SteveF

VEVOR Linear Rail 2PCS SBR16-1200mm Linear Slide Rail 4PCS SBR16UU Bearing Block CNC Kit Linear Rails and Bearings Kit CNC Rails Linear Rail Set forAutomated Machines and Equipments https://amzn.eu/d/fn1x4lV

This kind of thing. SBR16 Is the universal code I think. I got them cheaper on eBay used though. 

TTony

Thanks!

SteveF

A plethora of YouTube videos on making them but it’s pretty self explanatory tbh. Just have to make sure you make the cradle so that the bottom is level-ish with the bottom of the crossrails or it would probably be a bit high and might struggle to get the bit down (unless it’s a whopper like mine ) 

also I found I had to put strips of MDF under the side rails or the top rails wouldn’t clear a body blank. You can always then put a MDF sheet under the workpiece if you’re working on something thinner like a neck or fingerboard. 

hywelg

I did something similar with a 10x3 plank of sapele to make some window framesabout 10ft long. I used a bottom cutting bit I got off AliExpress. It was approx 40mm diameter.  My router is 2.3kw so didn't have a problem but I did run the router at full speed rather than slow revs. The problem using a slotting cutter is you always have to approach from the edge .

Yes that is sticking out too far , saw the shank off and file/grind it flat. 

SteveF

Worked a treat. A touch tricky to get the thickness just right. I used the masking tape/glue trick to hold it so need to take the thickness of the tape into account. 

Jez6345789

If thats the 48mm from Wealden great tool. The only thing to say is to watch the speed it stamped on the bit ISTR 12-15000 but I forgot to change from the default of 18000 on the cnc at work and it skimmed but burnt the wood will also do that when you need to flip the blade, Looks like you have the hang of it.

SteveF

I had my router on speed 2 which according to my googling is 11000.  It seemed to work ok, but I will see what it's like with it nudged up a touch next time.