Spiral vs shear - router bits

[Woodypk]

Hi guys,

I'm looking to spend a few quid on a new router bit for use in my router table for template trimming.

I'm about to batch out a load of European white oak parts using a 10mm polycarb template and need to decide whether its worth spending thrice the price on a 1/2" solid TC spiral bit or if a 1/2" shear cut TCT cutter will do the job.

I'll be double stacking the parts to give a total cut length of 40mm (to reduce the routing time) so will need to buy the 2" cut length bits.

I'm thinking wealden or whiteside. Infinity also do a shear cut bit at a price similar to the other brands.

Out of the two styles of cutters is the price difference of the spiral cutter worth it for ease of cut/accuracy/finish/reduced tear out? Or am I best in saving the difference so I can add to my 'nice to have but don't really need that tool' fund?

All edges, corners and faces will receive a final hand sand as part of the finishing process, but obviously a finer post router finish will result in less work sanding.

Cheers.

 

[Chunkytfg]

Spiral bits are generally better over straight bits however can I add another option to the list especially if you're doing batch work and likely to got through a few of them

This
https://www.scosarg.com/cmt-657-double-bearing-flush-trim-s-1-2-d-19-l-50with these
https://www.scosarg.com/hwm-knife-50x12x1-5
Spare blades are double sided meaning for £90 you essentially get 12 router bits and then each 10 bits after that are only £30.

 

[Droogs]

In the last few years, I have become rather fond of using compression bits for template work

 

[Woodypk]

Spiral bits are generally better over straight bits however can I add another option to the list especially if you're doing batch work and likely to got through a few of them

This
https://www.scosarg.com/cmt-657-double-bearing-flush-trim-s-1-2-d-19-l-50with these
https://www.scosarg.com/hwm-knife-50x12x1-5
Spare blades are double sided meaning for £90 you essentially get 12 router bits and then each 10 bits after that are only £30.

Chunky, thanks for the recommendation.

Unfortunately I need to start the project before the end of next week and that bit has a lead time of 31 days according to scosarg website.

In the last few years, I have become rather fond of using compression bits for template work

Droogs, would you say a compression bit is advantageous considering the template will protect the face of the work? Do you use a solid spiral type compression bit or a tct type one like the infinity?

 

[Buckeye]

I have a Wealden Up-Down Shear Trim (wealdentool.com) it is excellent.

 

[Spectric]

I'll be double stacking the parts to give a total cut length of 40mm (to reduce the routing time)

By double stacking your workpieces will this not mean having to take more shallower cuts so cancelling out any time savings. I would also say the Up-Down Shear Trim (wealdentool.com) it is great but no stock at present so also look at Mega Flush Trim Bits - Infinity Tools

 

[Woodypk]

By double stacking your workpieces will this not mean having to take more shallower cuts so cancelling out any time savings. I would also say the Up-Down Shear Trim (wealdentool.com) it is great but no stock at present so also look at Mega Flush Trim Bits - Infinity Tools

Spectric,
You may be able to help me out here... I'm fairy inexperienced to using a router table and routing in general.

My current workflow goes as follows:

Get stock to final thickness and flat.
double stack the two parts to be cut.
trace template onto the stacked parts and cut close to the line on the bandsaw approx 1-2mm away from traced line.
stick template onto the stacked parts within traced line and then take the extra 1-2mm off the stacked parts using the template (double sided taped to the top stacked part).

Up to now, I've never tried to skip out the bandsaw part of the job thus doing all the cutting on the router table. Is this not the way you'd carry out this operation? I've tried to save most of my time by carrying out all the cutting operations on two pieces of timber (both components of the final work piece) at once.

 

[Chunkytfg]

Chunky, thanks for the recommendation.

Unfortunately I need to start the project before the end of next week and that bit has a lead time of 31 days according to scosarg website.

This one doesnt and if youre using it on a router table the bearings at the correct end.

https://www.scosarg.com/cmt-657-flush-trim-bit-s-12-7-d-19x50-z2-rh-3382
I use the one I recommended in both a table and handheld so need the bearings at both ends.

I've got to wonder if the difference in time between doing one at a time versus double stacking them is actually worth it though.

 

[Droogs]

Most of my bits are Wealden ones, but for the compression bits I have the infinity as I found out about these before knowing the big W did them too

 

[Spectric]

Removing as much excess as possible without crossing the final line is the way to go but keep clear of the line. If the workpiece is built up from sections you may find there is a lot of variation in what needs to be removed and even with the bandsaw you can only do so much which is what I had recently when making a 550mm radius infill for under a shower tray that was 75mm high. The way I got round this was by fitting larger bearings to my cutter so that it initially took of less, basically it just removed the high points, by reducing my bearing size it slowly removed the high points until it was all the same excess and then a few final cuts and it was to template.

trace template onto the stacked parts and cut close to the line on the bandsaw approx 1-2mm away from traced line.

I would attach the template and cut close to it rather than trace a line to cut too and then attach the template, but others may do it other ways.

In my case the parts were layered so once one layer was done using a template the next layer once attached was done using the previous layer as the template but I am assuming you are making two identical components and being new to the table I would make them individual rather than both together. What you do not want is having too much material to remove or high points as trying to plough through to much material will give poor results and could be dangerous so getting roughly close to the template or using larger bearings is the way to go and doing 20mm at a time will be easier to control than 40mm if you are new to template work. One other bit of advice is with narrow stock, in these cases you may find making a larger template that sits on the table with the workpiece on top and guide bearing on the shank end rather than on the far end gives better stability and control with no risk of tilting.

 

[Woodypk]

This one doesnt and if youre using it on a router table the bearings at the correct end.

https://www.scosarg.com/cmt-657-flush-trim-bit-s-12-7-d-19x50-z2-rh-3382
I use the one I recommended in both a table and handheld so need the bearings at both ends.

I've got to wonder if the difference in time between doing one at a time versus double stacking them is actually worth it though.

Thanks for the second recommendation.

Chunky and Spectric, would you be able to explain what the benefits of cutting one at once would be? What would be your reasons to say it wouldn't be worth doing two stacked together? Surely if the router cutter edge is designed with a 50mm cutting length it should be able to handle two pieces totaling 40mm?

The components are shaped almost like a ' J ' but with a squared bottom a bit like the letter ' L '. I thought it would be a time saver to cut two pieces (bonded together) rather than route one piece at a time, removing the template, reattaching to the other and then running the same table routing process again?

Thanks to everyone who has replied so far... It's very helpful. I've been using workshop tools for many years now, but routing is still fairly new to me and finding the most efficient and safest way to complete a task is never a bad idea in my eyes.

Going back to the question for a moment... does anyone see the benefit of the spiral vs the TC tipped cutters? Seems those who have replied are using the TCT cutters. Droogs and Chunky, what made you decide to go for the cutters (and keep going for, I assume) vs using one of the other style of cutters?

 

[Chunkytfg]

Personally I used the Replaceable blades version as I mainly work with plywood and its murder on blades! plus I can keep a pack of blades in the draw and if it starts to dull I dont have to worry about making the bit last, I can just chuck in a new set and be back working in no time at all.


From the workflow perspective I would just think that the time difference is probably fairly small but if youre batching out alot of something then it can soon add up. Also as Spectric mentions putting 40mm of material against the cutter over 20mm is increasing the risk of it grabbing and doing damage. if that does happen then you lose 2 bits over just the one and also risk wrecking the template.

 

[Woodypk]

Brilliant, thanks for the info, Chunky.

 

[Droogs]

For me the Infinity were the first I was aware of and I am happy with the quality and cleanness of the arris at the edge of the cut on both sides that I get using them. I have not got to the point where I need to replace them but will look at others when the time comes. Also I really like the crispness of the bottom of internal corners of any rebate/grooves etc esp in softwood like deal for carcass framing joints.

 

[Spectric]

router cutter edge is designed with a 50mm cutting length it should be able to handle two pieces totaling 40mm?

If you are using the top bearing then just cutting 20mm will mean less cutter is exposed above the table and as you say you are new to table routing so it makes things safer and more controllable because less effort is needed to maintain a nice constant cut. I don't think anyone has mentioned that you need to feed right to left on a table as well, this direction you feed against the cutter and not with it which could take the workpiece from you.

I would suggest you practice using scraps to get a feel for the task in hand, you will find lighter cuts much more controllable than trying to plough off larger cuts and you have not mentioned what table or router you will be using, here power is important.

 

[John Brown]

I was cutting some simple curves in 18mm BB ply the other day, and had a really difficult time at one end of the piece. I think it was to do with where the pin was, but it was snatching alarmingly. Being ply, I figured it wasn't a grain direction thing.
Not that this is relevant to the OP, except to highlight that it can be a tricky operation for a beginner( I'm just a hobbyist, so fairly inexperienced).