Slitting saws and arbors, have zero experience. need info please.

[sycle1]

G'day
I am Considering buying a slitting saw for my bench mill.
My mill has a M3 taper and looking at buying an arbor and slitting saw blades to expand my milling functions.
There are a lot of variables, so my biggest question I guess is, do I buy an M3 arbor to suit the blades I want, or do I get a straight shanked arbor and use it with my M3 collet arbor.
Is one way any better or safer than the other?
Also regarding slitting saw blades, there is a wide variety in the size of centre mounting hole, is any size better or more available than another.
I notice a lot of Arbors don't have any keyway provision, is that a big issue in a small mill?
Probably won't use much bigger than 1/16th" thick blade or so with this machine.
Any info greatly appreciated.
Cheers

 

[mmcmdl]

I personally would buy a straight shank arbor or better yet , make a few with different size mounts . They can then be transferred to larger machines if you ever upgrade . As far as keys , not really a big deal unless going with a large cutter .

 

[Jim F]

This video show a shop made version and explains the reason and finer points.

 

[projectnut]

In most cases when deciding whether to make or buy a tool I look at several commercially available offerings, make a list of the materials and time needed to complete the job, and decide which is more economical. In this case I decided to go with a Shars arbor that fit my mill. Keep in mind this was a few years ago and the prices have risen dramatically since then.

I went with this one so I could use the cutters I already have for my horizontal mill. At the time it was selling for under $25.00. I would have been hard pressed to buy the materials for that price, and it would have taken me several hours to build. The same one today sells for just under $40.00
1" Stub Milling Machine Arbor (shars.com)

They also have a version for slitting saws only. It sells for under $25.00. They sell several other styles. All are in the $25.00 to $50.00 range.
Search results for: 'slitting saw arbor' (shars.com)

When it came to purchasing cutters I originally started buying those with a 1" keyed hole because that's the size of the arbor on my horizontal mill. After a while the 1" cutters became more expensive, mainly because hobbyists seem to prefer them as they have smaller mills. That's when I decided to make some adaptors for 1 1/4", 1 1/2" and 2" cutters. I ran across a seller on eBay with nearly 100 different width slitting saws for a 1 1/2" arbor. As Benmychree mentioned in another post they are relatively uncommon. As such I was able to buy them for less than $2.00 each

The adaptors I made are for slitting saws, and narrower cutters. I should have made them a bit wider as you'll see in the attached pictures. The one for 1 1/4" cutters isn't really wide enough for the cutter in the pictures. I only grabbed it because I didn't want to look through stacks of slitting saws to find one with the proper size hole.

The first 3 pictures are of the 1 1/2" adaptor



These are the 1 1/4" adaptor, note it's not really wide enough for this cutter. It was made for slitting saws



Here is the 2" adaptor



Here are all three. Left to right 1 1/2", 1 1/4", 2"

 

[Tozguy]

My vote is for the straight shank option.
The bore size will vary depending on the saw maker. Generally larger saws have larger bores.
So as not to be limited in your choice of saws, making adapters as you need them sounds like a good plan.
Locking pins or keys can be added anytime you might want to.

 

[Asm109]

Straight shank. You can change the cutter out with far less headroom to the vise or table than changing a complete M3 holder.

 

[Flyinfool]

+ 1 for straight shank, they can be used anywhere. I bought a set of no name arbors for 3 different sizes of cutter holes. I have had a need for each of the sizes over the years, so there is no one size fits all. If you are just buying one arbor, look thru the cutters at your favorite tooling suppliers to see what hole size and pricing is best suited to you.

As for buying new cutters just to have, I would not do that, wait until you have a need and then buy the cutter that you need. If you buy one for no purpose, Murphy say that it will be just a bit to thick or a bit to big or small in diameter for the cut you need to make. Now of course if you can score a deal on a pile of assorted cutters then buy all means go for a deal like that, I would, in a heart beat.

 

[mikey]

Slitting saw arbors are not difficult to make if you choose. Stefan G did a 2-part series on this and it is worth watching. And I agree with the other guys - go with a straight arbor that is simple to make. If you choose to buy one, Sierra American makes really good ones.

You will find that the depth of the slit/slot is what drives the choice of blade and arbor hole. The smaller the arbor hole in the blade, the smaller the arbor and the more exposed blade you have, which translates into greater depth of cut. Very often, you will just need a slot that closes to clamp a tool. It doesn't have to be wide but it often has to be deep so a thinner blade works, provided you have enough blade sticking out to go deep enough into the work piece.

It is for this reason that 1/2" arbor saws are so popular; the arbor diameter is small so you can get deeper before the body of the arbor runs into the work piece. I have 1/2" arbor saws from 2" OD to 4" OD and in varying thicknesses. Quite often, you will need a slot that is higher than any one blade you have. Most small 1/2" arbor saws are jewelers saws with no set to the teeth. This allows you to stack one blade on top of the other to create a thicker saw and get the job done.

The larger saws may have offset teeth or raked geometry. These cannot be stacked. You will find them with almost every diameter arbor hole and owning an arbor to fit them all gets expensive. Best to stick with arbors in the most popular sizes - 1/2", 3/4" and 1". You will find saws in all these sizes in almost any thickness you need on ebay.

Many larger saws have key slots in them. For hobby use, you do not need a keyed arbor.

 

[Flyinfool]

None of my arbors are keyed. My biggest saw is a 4" x .125 that I have used to cut deep into stainless steel, Titanium and aluminum. I have never had a saw of any size slip in any size of arbor cutting any material.

 

[sycle1]

Thanks for the great info much appreciated.