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DRA Qualtech DEWCBR3/16 3/16 X 3/32 Pilot Hole HSS Straight Shank Counterbore P13389221DRA-DEWCBR3-16 https://cdnimages.opentip.com/full/DRA/DRA-DEWCBR3-16.jpg Qualtech DEWCBR3/16 3/16 X 3/32 Pilot Hole HSS Straight Shank Counterbore Manufacturer Part Number: dewcbr3/16Counterboring is the enlargement of a portion of a hole that has previously been formedIf the counterbored portion is shallow (1/8\"\" or less), the operations is usually known as spot-facing; for example, a flat seat for a bolt head or nutIf the hole is enlarged to a considerable depth, it is designated as counterboringSize :3/16\"Overall Length :3\"Material :High Speed SteelFinish :Uncoated (Bright)Shank Size :15/64\"Decimal Equivalent :0.1875Metric Equivalent :4.7625mmShank Type :Round 13389221 887861128902 1.0000lbs 0.00 0.00 0.00
Qualtech
16.45 2026-04-26 25 In Stock
customer review - by , February 2, 2024
5/ 5stars
I bought several sizes of these but will just leave one review for this size option. They are the typical import tooling, nothing fantastic but serviceable - these do work fairly well. Best if you can slow down the RPM of course so if you're using in a drill press the slowest speed on most presses will be too fast - use cutting oil and mind your feed and technique in that case. I ran this one for 13 holes in 6061 and it was no worse for wear other than clinging metal (normal). With a lucky fit, I later used it as a full bore reamer for some short stainless (304 I think) shaft collars and it did surprisingly well there other than surface finish but did take a toll on the cutting edges, which I was able to touch up well enough. I used one of the other sizes in nylon and it was only ok there...not quite sharp enough for a high quality cut in that material (may do better in delrin, not sure how it would like polycarbonate...probably frustrating in soft plastics). So...good value, worth the purchase for hobby or occasional use in common and/or softer materials. Have to use these correctly, don't treat them like they're drill bits.
customer review - by , July 7, 2023
5/ 5stars
Very good product at an excellent price.
customer review - by , October 10, 2021
4/ 5stars
I bought this counterbore to repair a damaged crown on an M1 carbine. I turned a brass pilot to fit the bore properly and this did a great job. I used plenty of cutting oil and went slow and steady. It pulled nice chips and left a nice finish. I'd guess a 16 to 32 Ra. I did not expect this from a $20 counterbore. I thought I would have to finish lap it. Nope. The pilot hole was rough and oversized. It was advertised as 5/32 but measured .164 with pin gauges. Might not work with standard pilots.
customer review - by , August 8, 2021
4/ 5stars
First I have not used it yet. The one that I used survived the 220 holes that I had to countersink into the mild steel bars that I was milling. So once I put it to use I will update my response. The only disappointment is that it does not have a hole the diameter of the pilot through the tool. This comes in handy once in a while if the pilot just does not easily removable.
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Qualtech DEWCBR3/16 3/16 X 3/32 Pilot Hole HSS Straight Shank Counterbore

stars Rating 4.5 | 4 reviews
Brand Qualtech
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UPC: 887861128902
SKU: DRA-P-383
Price:
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Quantity:
25 In Stock
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Product Description

Manufacturer Part Number: dewcbr3/16

  • Counterboring is the enlargement of a portion of a hole that has previously been formed
  • If the counterbored portion is shallow (1/8"" or less), the operations is usually known as spot-facing; for example, a flat seat for a bolt head or nut
  • If the hole is enlarged to a considerable depth, it is designated as counterboring


    • warning tips WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.
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    Customer Reviews
    4.5 out of 5
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    Write a Review
    By J Osborne
    Date: February 21, 2024
    I bought several sizes of these but will just leave one review for this size option. They are the typical import tooling, nothing fantastic but serviceable - these do work fairly well. Best if you can slow down the RPM of course so if you're using in a drill press the slowest speed on most presses will be too fast - use cutting oil and mind your feed and technique in that case. I ran this one for 13 holes in 6061 and it was no worse for wear other than clinging metal (normal). With a lucky fit, I later used it as a full bore reamer for some short stainless (304 I think) shaft collars and it did surprisingly well there other than surface finish but did take a toll on the cutting edges, which I was able to touch up well enough. I used one of the other sizes in nylon and it was only ok there...not quite sharp enough for a high quality cut in that material (may do better in delrin, not sure how it would like polycarbonate...probably frustrating in soft plastics). So...good value, worth the purchase for hobby or occasional use in common and/or softer materials. Have to use these correctly, don't treat them like they're drill bits.
    Rating: 5 stars [5 of 5 Stars!]
    By Hamm
    Date: July 20, 2023
    Very good product at an excellent price.
    Rating: 5 stars [5 of 5 Stars!]
    By Glenn S.
    Date: October 17, 2021
    I bought this counterbore to repair a damaged crown on an M1 carbine. I turned a brass pilot to fit the bore properly and this did a great job. I used plenty of cutting oil and went slow and steady. It pulled nice chips and left a nice finish. I'd guess a 16 to 32 Ra. I did not expect this from a $20 counterbore. I thought I would have to finish lap it. Nope. The pilot hole was rough and oversized. It was advertised as 5/32 but measured .164 with pin gauges. Might not work with standard pilots.
    Rating: 4 stars [4 of 5 Stars!]
    By Kenneth Olsen
    Date: August 16, 2021
    First I have not used it yet. The one that I used survived the 220 holes that I had to countersink into the mild steel bars that I was milling. So once I put it to use I will update my response. The only disappointment is that it does not have a hole the diameter of the pilot through the tool. This comes in handy once in a while if the pilot just does not easily removable.
    Rating: 4 stars [4 of 5 Stars!]
    Items 1 - 4 of 4 reviews
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