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techtalk:ref:tools147 [2019/05/09 21:02] hippysmack [Rocker Arm Bushing Reamer (94804-57)] |
techtalk:ref:tools147 [2019/05/09 21:57] hippysmack [Pre-Ream Hole Size Chart] |
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- | ===== Pre-Ream Hole Size Chart ===== | + | ===== Calculating Pre-Ream Drill Hole Sizes ===== |
+ | The amount of material left in the hole prior to reaming (pre-ream hole size) plays an integral role in the quality of the reamed hole. ((http://blog.supertoolinc.com/2012/04/06/pre-ream-hole-size/)) \\ | ||
+ | The pre-ream hole size affects characteristics in the reamed hole including hole finish, hole straightness, tool life, and cycle time. \\ | ||
+ | There are several ways in which the pre-ream hole size may be obtained some examples include investment casting, boring, line boring, rough reaming, and stamping. \\ | ||
+ | The most common way to obtain the pre-ream hole size is through drilling. \\ | ||
+ | The appropriate amount of stock removal for carbide tipped and solid carbide reamers is generally 2% to 3% of the finished hole size. \\ | ||
+ | Carbide tipped and solid carbide reamers need to have adequate stock to remove or they will rub in the hole and generate excessive heat. \\ | ||
+ | This leads to premature tool wear and poor hole finishes. | ||
+ | A 0.7500” diameter reamer should remove between 0.0150”-0.0225” of stock. \\ | ||
+ | A 0.2500” diameter reamer should remove between 0.0050”-0.0075” of stock. \\ | ||
- | ^Reamer diameter \\ fraction - decimal (nominal)^Hole size \\ to leave 2%^Drill size \\ to leave 2%^Hole size \\ to leave 3%^Drill size \\ to leave 3%^ | + | A good way to calculate the drill bit size is to take the desired finished hole diameter and multiply it by 0.98 \\ |
- | |1/8 - .1250|.1225|31|.1213|3.0mm| | + | Then take the desired finished hole size and multiply it by 0.97 \\ |
- | |9/64 - .1406|.1378|29|.1364|3.4mm| | + | This gives you the range of stock removal best suited to the finish ream hole size. \\ |
- | |5/32 - .1562|.1532|24|.1516|25| | + | From that range refer to a standard drill chart to chose the appropriate standard drill size for your pre reamed hole size. \\ |
- | |11/64 - .1719|.1685|19|.1667|4.2mm| | + | Below are examples for calculating the pre-ream drill hole size for a 0.7500” finished hole diameter and a 0.2500” finished hole diameter. |
- | |3/16 - .1875|.1838|14|.1819|15| | + | |0.7500" x 0.98 = 0.7350"|0.7500" x 0.97 = 0.7275"| |
- | |13/64 - .2031|.1990|5.0mm|.1970|9| | + | |
- | |7/32 - .2188|.2144|5.4mm|.2122|4| | + | |
- | |5/64 - .2344|.2297|1|.2274|5.7mm| | + | |
- | |1/4 - .2500|.2450|C|.2425|6.1mm| | + | |
- | |17/64 - .2656|.2600|6.5mm|.2576|F| | + | |
- | |9/32 - .2812|.2756|I|.2728|6.9mm| | + | |
- | |19/64 - .2969|.2910|7.3mm|.2880|7.25mm| | + | |
+ | Therefore, the appropriate range of the pre-ream drill hole size for a 0.7500” finished hole; \\ | ||
+ | 0.7275” – 0.7350” \\ | ||
+ | |||
+ | |0.2500" x 0.98 = 0.2450"|0.2500" x 0.97 = 0.2425"| | ||
+ | |||
+ | Therefore, the appropriate range of the pre-ream drill hole size for a 0.2500” finished hole; \\ | ||
+ | 0.2425” – 0.2450” \\ | ||
+ | |||
+ | If you are fine tuning your operation and are within the 2%-3% range; \\ | ||
+ | Try removing 2% of the reamer diameter for steels and tough alloys.. \\ | ||
+ | And 3% for non-ferrous and cast iron materials.. \\ | ||
+ | If you are rough reaming, stock removal can be up to 5% of the reamer diameter. \\ | ||
+ | |||
+ | The 2%-3% rule is great in theory. \\ | ||
+ | In the real world drill bits come in standard sizes. \\ | ||
+ | Most do not have time or money to wait for a special size drill bit to be made. \\ | ||
+ | You are usually forced to choose among standard drill bit sizes that are on the shelf. \\ | ||
+ | A Pre-Ream Drill Hole Size Chart below to help with this selection. Click here to download a printable PDF of the Pre-Ream-Drill-Hole-Size-Chart. This chart tells the appropriate standard drill bit size to choose when reaming fractional diameters from 1/8” to 1” in 1/64” increments. This chart allows for drill oversize based on research done by the United States Cutting Tool Institute. | ||
+ | |||
+ | ===== Pre-Ream Drill Hole Size Chart ===== | ||
+ | From Rock River Tool Inc. ((https://www.rockrivertool.com/documents/pre-ream-drill-size-chart.pdf)) | ||
+ | ^Reamer diameter \\ fraction - decimal (nominal)^Hole size \\ to leave 2%^Drill size \\ to leave 2%^Hole size \\ to leave 3%^Drill size \\ to leave 3%^ | ||
+ | |1/8" - .1250"|.1225"|31|.1213"|3.0mm| | ||
+ | |9/64" - .1406"|.1378"|29|.1364"|3.4mm| | ||
+ | |5/32" - .1562"|.1532"|24|.1516"|25| | ||
+ | |11/64" - .1719"|.1685"|19|.1667"|4.2mm| | ||
+ | |3/16" - .1875"|.1838"|14|.1819"|15| | ||
+ | |13/64" - .2031"|.1990"|5.0mm|.1970"|9| | ||
+ | |7/32" - .2188"|.2144"|5.4mm|.2122"|4| | ||
+ | |5/64" - .2344"|.2297"|1|.2274"|5.7mm| | ||
+ | |1/4" - .2500"|.2450"|C|.2425"|6.1mm| | ||
+ | |17/64" - .2656"|.2600"|6.5mm|.2576"|F| | ||
+ | |9/32" - .2812"|.2756"|I|.2728"|6.9mm| | ||
+ | |19/64" - .2969"|.2910"|7.3mm|.2880"|7.25mm| | ||
+ | |5/16" - .3125"|.3063"|7.75mm|.3031"|N| | ||
+ | |21/64" - .3281"|.3215"|8.1mm|.3183"|O| | ||
+ | |11/32" - .3438"|.3370"|8.5mm|.3335"|8.4mm| | ||
+ | |23/64" - .3594"|.3522"|S|.3486"|8.8mm| | ||
+ | |3/8" - .3750"|.3675"|9.25mm|.3638"|23/64| | ||
+ | |25/64" - .3906"|.3828"|9.6mm|.3789"|V| | ||
+ | |13/32" - .4062"|.3982"|10.0mm|.3941"|25/64| | ||
+ | |27/64" - .4219"|.4135"|10.4mm|.4092"|13/32| | ||
+ | |7/16" - .4375"|.4288"|10.8mm|.4244"|27/64| | ||
+ | |29/64" - .4531"|.4440"|11.2mm|.4395"|7/16| | ||
+ | |15/32" - .4688"|.4594"|11.6mm|.4547"|29/64| | ||
+ | |31/64" - .4844"|.4747"|12.0mm|.4699"|15/32| | ||
+ | |1/2" - .5000"|.4900"|31/64|.4850"|12.2mm| | ||
+ | |33/64" - .5156"|.5053"|1/2|.5000"|12.6mm| | ||
+ | |17/32" - .5312"|.5206"|33/64|.5153"|13.0mm| | ||
+ | |35/64" - .5469"|.5360"|17/32|.5305"|13.4mm| | ||
+ | |9/16" - .5625"|.5513"|35/64|.5456"|13.8mm| | ||
+ | |37/64" - .5781"|.5665"|9/16|.5608"|14.2mm| | ||
+ | |19/32" - .5938"|.5820"|37/64|.5760"|14.5mm| | ||
+ | |39/64" - .6094"|.5972"|19/32|.5911"|14.9mm| | ||
+ | |5/8" - .6250"|.6125"|39/64|.6063"|15.3mm| | ||
+ | |41/64" - .6406"|.6278"|5/8|.6214"|15.7mm| | ||
+ | |21/32" - .6562"|.6431"|41/64|.6365"|16.1mm| | ||
+ | |43/64" - .6719"|.6585"|21/32|.6517"|16.5mm| | ||
+ | |11/16" - .6875"|.6738"|17.0mm|.6669"|16.8mm| | ||
+ | |45/64" - .7031"|.6890"|11/16|.6820"|17.2mm| | ||
+ | |23/32" - .7188"|.7044"|45/64|.6972"|17.6mm| | ||
+ | |47/64" - .7344"|.7197"|18.2mm|.7124"|18.0mm| | ||
+ | |3/4" - .7500"|.7350"|18.5mm|.7275"|18.3mm| | ||
+ | |49/64" - .7656"|.7502"|18.9mm|.7426"|18.8mm| | ||
+ | |25/32" - .7812"|.7656"|19.3mm|.7578"|3/4| | ||
+ | |51/64" - .7969"|.7810"|19.7mm|.7730"|49/64| | ||
+ | |13/16" - .8125"|.7963"|20.1mm|.7881"|25/32| | ||
+ | |53/64" - .8281"|.8115"|20.5mm|.8034"|51/64| | ||
+ | |27/32" - .8438"|.8270"|20.8mm|.8185"|13/16| | ||
+ | |55/64" - .8594"|.8422"|21.25mm|.8336"|53/64| | ||
+ | |7/8" - .8750"|.8575"|21.6mm|.8488"|27/32| | ||
+ | |57/64" - .8906"|.8728"|22.0mm|.8639"|55/64| | ||
+ | |29/32" - .9062"|.8881"|22.5mm|.8790"|7/8| | ||
+ | |59/64" - .9219"|.9035"|22.8mm|.8942"|57/64| | ||
+ | |15/16" - .9375"|.9188"|23.25mm|.9094"|29/32| | ||
+ | |61/64" - .9531"|.9340"|23.5mm|.9245"|59/64| | ||
+ | |31/32" - .9688"|.9494"|24.0mm|.9397"|15/16| | ||
+ | |63/64" - .9844"|.9647"|24.4mm|.9549"|61/64| | ||
+ | |1" - 1.0000"|.9800"|24.75mm|.9700"|31/32| | ||
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