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Tool Poor quality DIMARCanada Counter Sink bit

Tool
jcdammeyer

jcdammeyer

John
Premium Member
I bought this DIMAR Canada counter sink from KMS Tools. There was a very rough ridge of metal on the cutting edge which I cleaned off with a diamond stone. But it's not a 90 degree countersink. More like an arc'd counter sink with one point being 90 degrees.

DIMAR told me to return it to KMS Tools and they could contact DIMAR to arrange a credit with them. I told them I could already return it to KMS Tools since their return policy is so good. But since I'd already started sharpening it it KMS might give me more trouble. In either case I told DIMAR that had expected them to grab one from their inventory, sharpen it properly for me and replace it.
Yeah like that would really happen but it was worth a shot.
DIM-202C12_closeup.jpg

Now granted, from KBC Tools the 6 flute version is only a few dollars more and from the photo on their web site looks perfect with straight edges but what a real one would look like is another thing.

And the sets with the single flutes are way more expensive.

KEO,90DEG COBALT KEO S/F COUNTER SINK SET,1-159A-50059,KBC Tools & Machinery

KEO,90DEG COBALT KEO S/F COUNTER SINK SET,1-159A-50059,KBC Tools & Machinery
www.kbctools.ca www.kbctools.ca

Likely I will get one of these sets the next time I'm in Vancouver.

KBC,NO.0-4 90DEG CSINK & DEBURRING TOOL SET,1-2529-200,KBC Tools & Machinery

KBC,NO.0-4 90DEG CSINK & DEBURRING TOOL SET,1-2529-200,KBC Tools & Machinery
www.kbctools.ca www.kbctools.ca
 
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Looks like cheap stuff sold also at Princess Auto. I think they are meant for wood or something like that. Check the steel type used via sparks as it may be non M2 or M35 or M43 but just tool steel like 4140 or even 1045. I.e. sharpening these will not get you as far as you think.
 
They are sending me this one. It's almost like it's a different tool bit.
1692219703025.webp


Compared to what I have here.

1692219803486.webp
 
I was surprised that they offered to send a replacement. They claimed they thought I just wanted a refund. Even the replacement has some roughness to it from what I can see if the five 1MB photos they sent.

I've been pondering all morning, how to hold the bit so I can use a very fine stone to resharpen it. I have hex 5C collets and my spin indexer. I have CNC so I don't have to pivot the table to 45 degrees although it might be easier.

Project 42 is a Quorn Tool and Cutter Grinder but I want to finish the Project 42 Robot arm first.
 
jcdammeyer said:
They are sending me this one. It's almost like it's a different tool bit.
Click to expand...

The edge in the second photo is a joke and the one in the first picture is just less funny but still not great (unless the photo is misleading).

If they let you keep it, I'd be tempted to try a small disk in a Dremel Tool (or similar) on this surface grinding toward the edge. Nothing to lose cuz it won't work well like that!


Screenshot_20230816_184238_Chrome.jpg
 
Well the shank of that cutter is supposed to be hex 1/4" but measures across the flats 0.24" rather than 0.25". On the South Bend I can pull the collet and tighten down on the shank. But my spin index doesn't seem to be able to pull hard enough to tighten. Very strange.
I guess it's going to be 3 jaw chuck on rotary table instead.
 
Susquatch said:
The edge in the second photo is a joke and the one in the first picture is just less funny but still not great (unless the photo is misleading).

If they let you keep it, I'd be tempted to try a small disk in a Dremel Tool (or similar) on this surface grinding toward the edge. Nothing to lose cuz it won't work well like that!


View attachment 37535
Click to expand...
Likely they will let me keep it or else ask me to take it back to KMS Tools. That's why I haven't gone any further with sharpening plus that it doesn't fit in the collet.
 
No
Degen said:
Its been used prior to you getting it.
Click to expand...
It was vacuum packed underneath plastic onto the cardboard. I could catch my fingernail on each cutting edge lip from bad grinding and the titanium (or whatever the gold stuff is). So I took my diamond sharpening plate and ran each edge flat along the edge of the plate. That's why there's a bit of silvery looking edge along the cutting edge.

I tried it first before the diamond plate into MDF. Pretty ugly hole. Then after the cleanup into MDF. Nicer hole but still a bit rough. Then into some aluminum 6061. That's why some of the areas look like the gold has been worn. I did that. Although it made what looked like a countersunk hole it wasn't 90 degrees.

When I putting bluing on the cut area and spun a metric flathead it made a barely visible thin line. And an imperial flathead also didn't really make contact.

Compared to the 82 degree countersink bit which allowed the imperial flathead to leave a wide impression in the bluing. But then that first picture shows the straight edge and how badly ground the bit is. The one they are replacing it with looks much straighter.
 
I ordered this set on 09AUG23. Came today Canada Post.
1692310336740.png
There's about 0.006" runout when held in a collet. It makes a reasonable countersink in a 4mm hole drill in Aluminum. With bluing the head leaves a wider mark so I think they're are good. I ran it at 200 RPM. Manual down feed with the quill.

Edit: Fix spelling mistakes.
 
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Final comment on this until the new DIMAR one arrives. Made a small wooden base for the Chinesium grade metal. Note it says HSS on the shank. Yet I can, with a file on the back side of the cutting part (underneath where it does no harm) file a groove.

I don't think I'm supposed to be able to do this with HSS. These will work for wood if I need 90 degree counter sinks. Might even work in the softer cast aluminum. Harder aluminum... not so much.

1692328423005.webp
 
Here's a closeup that shows that these really cannot be HSS. Don't think I should be able to file a groove in it.
Not_HSS.jpg
 
ttlrfrank said:
Looks like the usual Asian 'we make stuff...that looks like stuff'..maybe gold-painted pewter?:rolleyes:
Click to expand...
I didn't order it from the manufacturer but just some AliExpress Store. For all you know the manufacturer screwed up and forgot to harden a bunch before plating. Once they figured out the batch was screwed it was cheaper and easier to unload into the AliExpress world for woodworking which doesn't _need_ high speed steel although it's better of course.
Or maybe they used standard steel rather than HSS tool steel when they made them and then when they wouldn't harden decided not to throw them out.
One has to remember I paid only $16 including shipping for these. So I totally expected garbage but I'm hoping they will work for cast aluminum.
After all this set from KBC Tools isn't cheap.

KEO,90DEG COBALT KEO S/F COUNTER SINK SET,1-159A-50059,KBC Tools & Machinery

KEO,90DEG COBALT KEO S/F COUNTER SINK SET,1-159A-50059,KBC Tools & Machinery
www.kbctools.ca www.kbctools.ca
 
I mentioned this in my Robot arm thread but thought I'd update this one too with the link to that message.
canadianhobbymetalworkers.com

Robot Arm

Installed the boring bar. Tweaked it to just shave the hole round. Now it's about 25.14mm instead of 25mm but good enough to locate the motor and it still lines up with the screws. Time to order all the metric socket and flat head screws. And one more flange to make. The photo also shows...
canadianhobbymetalworkers.com canadianhobbymetalworkers.com
 
I'm finally starting to delve into my TCG (tool cutter grinder). I'll post separately because its a bit of story unto itself & I am just at early stages of understanding what all the knobs & motions do, now that some machine issues have been remediated.

Today I took a crack at redressing a HSS single lip countersink with Kryptonite Brown coating. I closely matched the 90-deg included angle & tried to match the minimal back rake helix angle. I'm a bit unclear on the back rake because now that I look at my set more closely for the first time, they seem randomly different. Anyways you can see the conical surface was not that great to begin with even before the coating was applied as evidenced by the surface discontinuity & patch of Kryptonite still remaining. I think there is at least 0.010" off redressing at this point. The cutting action improvement was quite dramatic. Probably due to much sharper restored cutting edge but suspect improved cone geometry surely helped. I also started paying attention to the angled through hole which forms the cutting edge. if its ratty (which it is) it just transfers this to what becomes a saw-toothy edge when new cone angle is ground. So next one I'll first clean up the hole with a diamond burr. Anyways, your post reminded me of this topic.

Actually I have been reasonably happy with these countersinks. they seem to work despite themselves. But hopefully I now have a means to tune them up & extend life. I also have a set of HSS single lip cutters (not pictured) which are nice & sharp & seem accurate to the eye, but just not happy with the finish. By accident I got my relief helix wrong. Its maybe 3-deg vs +10-deg but amazingly they cut much better that way. More experimentation required.

1693794234502.png
1693794262071.png
 
An update on the tool bit I bought from KMS. Got an email from them requesting I return it for replacement. Brought it and the one DIIMAR sent me to show them how bad it was. We compared it to the other two plastic wrapped ones they had in stock. Those two were only a shade better but still pretty junky.

The other one they had was in the same plastic container like the one I received directly from DIMAR. It looked as nice as the one DIMAR sent me. In fact one cutting edge was sharpened nicer than mine. And then out of the blue he offered to swap that one for the one I had. Super nice.

So kudos to both DIMAR and KMS for after sales support!
 
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