Depends on the slitting saws. I have 13mm, 16mm, 22mm and 1″, all with R8 shanks

1″ used to be the norm but I’m not sure any longer.

Dave

I’ve made my own for a while now following a bad experience with a “universal” on…

Jimb

Classic bikes are likely to want imperial cuts so the saws tend to have imperial holes. 1″ would be my choice in that case and a 3″ dia saw as anything bigger in steel needs to be run a bit faster than ideal if the 2.7 is not to stall. Smaller saws will also tend to have a smaller bore but they also have a shallower cutting depth so unless you want to buy a lot of saws stick with the 1″ x 3″ option, maybe 4″ for non ferrous.

If you are not bothered by width of cut then 22mm bore and 80mm dia saws would be a reasonable choice for that machine.

Good prompt at this time of year and with my off-spring asking for Christmas suggestions.

I think that all my slitting saws are 1″ bore – which fit my Horizontals. However for the new Seig, I purchased both 16mm and 22mm arbors (during Ketans fire sale – thinking mostly about gear cutters at the time). I probably need an R8 1″ too…so must add to the list.

Andy, I’m not sure that it makes much diference to you if the saw is Imperial or Metric but I’d guess you will be needing ‘heavier’ (larger) saws for your work. You can still get Imperial saws new (with 1″ bores) here in UK and they are out there in quantiy 2nd hand too. So I think 1″ would suit but if you want to be all Metric then I’d go for a 22mm arbor for the larger saw sizes.

Regards,

IanT

Metric slitting saws equals metric arbor, imperial slitting saws equals imperial arbor. Most of my slitting saws are imperial so I use 1″ and 1-1/4″ arbors on the horizontal mill. For deep cuts with slitting saws I prefer to use the horizontal mill as I’ve found slitting saws on the vertical mill go walkies with deeper cuts. Slitting saws on the vertical mill are limited to shallow cuts, such as slotting screw heads.

For the vertical mill I have a 1″ diameter R8 slitting saw arbor. I’ve never felt the need for other sizes. While slitting saws on the vertical mill are mostly limited to shallow cuts, with care larger cutters can be used:

The slot was roughed out using an endmill and the side and face cutter only used to bring the slot to final width and create the sharp internal corners.

Julie

I wonder why manufacturers generally supply slitting saws with keyways if they shouldn’t be used?

Julie

I don’t use the keyway with slitting saws on either the lathe or horizontal but then I’m not trying to push them very hard. I would generally use one of my horizontals for this work, as the arbor can then be supported at both ends and this helps prevent the “walkies” that Julie refers to. I have vertical heads for both my horizontals but can’t recall ever using a (slitting) saw with them, although I’ve certainly used them on my lathes…maybe having the Sieg will change my habits in this respect.

However, when using plain (heavier) milling cutters on the horizontals, I do use the keyway as (with deeper/wider cuts) the cutter will tend to ‘spin’ on the arbor if not secured. Plain milling cutters are normally run at lower speeds than a slitting saw, which may (or may not) also be a factor. I haven’t thought too deeply about it but it’s the way (The Sainted) Pete & Norm taught me to do it a very long time ago.  🙂

Regards,

IanT

I can’t immediately find it but recall that I bought one of the keyless slitting saw holders as shown by JasonB. It was hopeless, out of true in the round, and axially, so the slitting saw wobbled in two directions.

If the slitting saw has a keyway I use it. On the vertical mill the slitting saws aren’t driven hard, mostly shallow slots. On the horizontal mill I drive slitting saws harder. They are mostly used for cutting up hot rolled steel stock into suitably sized blanks. I usually run around 30 to 50 rpm, 4 thou per tooth and depth of cut up to 3/8″ per pass. On the horizontal mill I use flood coolant.

Julie

I wonder why we don’t tend to use keys in other similar items, I can think of quite a few that I have and none use any form of positive drive to the cutter. What makes a slitting saw need a keyway when other items don’t?

Table saw

Radial arm saw

Cross Cut Mitre saws

Mains and cordless circular saws

Biscuit joiner

Various disc type router cutters

Spindle moulder tooling

Wet diamond saw

9″ and 115mm angle grinders

This is where old school practice does not meet well with modern bench top machines.

As Cedric says a slitting saw generally ends up running slowly as cutting speed is calculated using diameter simple rule of thumb for HSS in steel is 75 – 100ft/min which equates to approx 75 -100rpm.

These slow speeds combined with a 4″ diameter work OK on older machines with gear or belt speed change as the motor can be kept at optimum speed even though the spindle is slow. However a modern brushed or brushless variable speed machine needs it’s motor running right at the bottom of it’s speed range to get the spindle to also run slowly and becomes a bit gutless.

Back to my first reply where I suggested 3″ or 80mm saws and mentioned stalling. Using the minimum saw diameter to give the depth of cut will allow the spindle to run faster but you are likely to have to exceed the book speeds, even an 80mm saw will need to be run faster in steel unless it is a very shallow cut. Not so bad in aluminium as you can run about 3 times as fast but may need to keep depth of cut and feed rates in all materials a lot lower than the Likes of Julie are able to take so hand feed and not too deep per pass. The Sieg powerfee ddoe snot go anywhere near slow enough

I did this video some time ago of the SX2.7 with an 80mm saw cutting 12mm steel. Starts off at book speed 100rpm and just stalls but manages OK when the saw is run faster than the usual recommended speed at 210rpm.

Also note the use of a coarse tooth saw, use these for anything of thickness so the gullets don’t fill with swarf, keep the fine tooth saws for slitting screws etc.

For slitting alloy fork yokes, 50mm slitting saws might work, as the yokes are , what, 13-16mm thick? Smaller diameter slitting saw will give less radius at the end of the slot, which is a bit neater.

So 50mm slitting saw on aluminium could run at 400+ rpm. Keep plenty of WD40 on it for cutting fluid with ally.

I notice the 50mm blades have no keyway. They are thin and fragile so a bit of slip rather than jam and explode, as they can, may be a good thing.