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Helpful Hints For Saw Users

     These are general suggestions and where to start, and must be varied to meet a particular application.  We do not assume any liability in the following statements.  These STOCK saws will do the job.  Variations,  such as number of teeth, rake angle, clearance angle, bevel, side clearance, material, land, etc. may do it better, but set-up charges and lead time must be considered.

SPEEDS   - With a good set-up the speeds in the table below should be attained
                    - Reduce the speed for hard ( over Rockwell c30)  and abrasive materials, and for deep cuts
                    - Increase the speed for "free-machining" and non-ferrous metals.

Saws: M-2 Steel, Ground Teeth, 0 Rake Angle

Material to be Cut Saw
Diameter:
1-3/4" 2-1/4" 2-3/4" 3" 4"

Coolant

    Teeth - R.P.M. Teeth - R.P.M. Teeth - R.P.M. Teeth-R.P.M. Teeth -R.P.M.  
Mild Steel 64  -  450 60 - 350 56 - 275 56 - 250 72 - 200

Cutting Oil

Alloy Steel 64  -  200 60  - 175 56 - 150 56 - 125 72 - 100 "
Stainless Steel 64  -  200 60 - 175 56 - 150 56 - 125 72 - 100 "
Steel Castings 64  -  200 60 - 175 44 - 150 44 - 125 60 - 100 "
Steel Forgings 64  -  450 60 - 350 56 - 275 56 - 250 72 - 200 "
Monel 64  -  200 60 - 175 56 - 150 56  - 125 72 - 100 "
Aluminum 64 - 2000 60 - 1750 44 - 1350 44 - 1250 60 - 950

Soluble Oil

Bronze 74  -  750 60 - 600 44 - 500 44 - 450 60 - 350 "
Yellow Brass 64 - 2500 60 - 2000 44 - 1600 44 - 1500 60 - 1100 "
Copper 64 - 1750 60 - 350 44  - 1100 44 - 1000 60 - 750 "
Malleable Iron 64  -  350 60 - 250 56  - 200 56 - 200 72 - 150 "
Cast Iron 64  -  450 60 - 350   44 - 275 44 - 250 60 - 200

Dry

Die Castings 64 - 2500 60 - 2000 44 - 1600 44 - 1500 60 - 1100 "
Brittle Plastics 64  - 1000 60 - 900 56 - 700 56 - 650 72  -  500 "
Flexible Plastics Use Set Teeth (Hub saw with maximum side clearance for very thin cuts)

(There should be at least 2 teeth engaged in the cut.)

Increase Number of Teeth For:

- Thin Material
- Sandy Castings
- Thin Cuts (0.025)
- Thin Castings
- Slow Spindle Speeds
- Work Hardened
- Hard Material
- Hard Spots

Decrease Number of  Teeth For

 - Chip Clearance and Tooth Strength
     (Consider MSL & SMF type saws.)
- Deep Cuts (over 1/4")
- High Speeds
- Free Cutting Material

 

FEEDS - will vary from 0.0002" to 0.002" per tooth.  We suggest starting with the cutter described above and trying to arrive at  the condition described under "Cutting Fluids" by varying the Feed and Speed.  A straw color is the limit.  The saw loses its temper when it starts turning blue.

CUTTING FLUIDS- (to cool, lubricate, and wash the chips away.)
Cutting Oil
- use a 4% sulphur homogenized cutting oil.
Soluble Oil
- use 40-1 solution of soluble oil - (Mix thoroughly on a 4-1 solution before adding to tank.)       Increase speed and feed until the lubricant starts to give off a slight vapor (smoke).  Frequently saws are run too slow, causing rubbing and premature wear.

DISH - (Side Clearance or Hollow Grind)  Increase it for stainless steel and tenacious metals such as copper, zinc, tin or lead.

MOUNTING OF SAWS - Breakage - Wobble - Rubbing: These problems may be caused by the way the washers are mounted an either side of the saw.  - Washers drive the saw, in the absence of a driving key, and must always be clean, flat and bur-free.  A Speck of dirt will let the saw wobble and cut oversize.  If a saw breaks, it may score the washers.  Check marks around the saw hole for: Dirt, Shiny Spots ( as small as a pinpoint, indicating chips imbedded under the washers), and Circular Skid Marks, which indicate the nut is not tight.  - Thin saws should especially be supported by washers as large as possible.  Nut must be wrench-tight.  - If the saw blade pauses momentarily in its rotation while the feed advances, it will break.  - Washers must be of equal diameter or they will flex out the dish and cause one side of the teeth to rub.

TEETH -Deep cuts and soft material require  fewer teeth (for chip clearance) and stronger teeth (landed).  - Thin material requires more teeth (at least 2 teeth engaged in cut).  - Hard materials and narrow slots (under 0.025") likewise require more teeth. - Alternately beveled teeth keep chips from sticking in the cut and in the tooth gullets.  - Rake Angles: On the center for iron and steel, 5 negative for yellow brass, from 5 to 10 positive for the other soft materials.

BREAKAGE - In addition to causes noted under "MOUNTING OF SAWS": Teeth break when a starting a cut at too fast a speed, spindle bearings worn, drive belts loose or sheaves worn, indexing before saw has cleared the slot, work-piece not tight, or the saw is dull (even the best eventually wear out).

KEYWAYS - No keyways are furnished on saws under 0.020".  Thin saws will warp in the heat of treating and grinding processes.  Locked up between good supporting washers, they will run true.

HUBS - will allow maximum side clearance when attempting to cut wood or plastics.  They are helpful when Spacing saws on an arbor. 

RESHARPENING - In addition to grinding the tips of all the teeth, all marks must be removed from the sides of the teeth.  This can be done by grinding the diameter below the marks or, as we do, by grinding the tips and clean-up grinding the sides.  Either way the thickness is reduced because of the hollow grind that is necessary for even the shallowest of cuts. 

VIBRATION AND CHATTER - Arbor bent or worn undersize.  - Work-piece improperly supported, particularly watch on thin material.  - Teeth too coarse/fine.  -Speed too slow.  - Climb milling, "Up-milling" is preferred, but climb milling may help on small parts to keep them from being ripped from the clamping fixture.  It may also reduce the bur.  - Dull tool / Wrong clearance angels.   - Feed too slow.  

EXCESSIVE WEAR - Seizing: Not enough coolant in the right place.  - Not enough side clearance.  - Cutter speed too fast and feed too slow.  The work may glaze and the saw will rub.

TOLERANCES - are expensive, don't over-specify.

STEELS - M-2 is the best if the set-up is proper.  We do have available saws from M-24 along with various surface treatments such as Titanium Nitride. 

SUGGESTION - If a saw is working well, send it to us and we will duplicate it.  - If a saw is not working well, send us a used blade.  We can some times make recommendations from the marks on the saw.

Other Types and Special Saws

In addition to the types of Saws shown under Metal-Working & Mica Saws we are in a position to furnish other special purpose saws up to 6' diameter.  Features that can be incorporated into a special saws include:

>>Metric Dimensions.
>>Knives - straight or beveled edges.
>>Blanks - hardened and ground (grind your own teeth).
>>Thicknesses above are below our   standard ranges
>>Other O.D.'s and I.D.'s.
>>Tolerances on any dimension.
>>Angled Teeth.
>>Special tooth design: including bevels, back-off, land and rake angle.
>>Special side clearance (dish or hollow-grind)
>>Hubs of various sizes.
>>Special keyways or pin holes.

Quotations will be made promptly upon receipt of your specifications

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