Some bits from the set don't fit my router collet

[radhak]

Yesterday I needed to use one particular router bit the first time, and I found it did not fit the collet. It just went in about a quarter of the shank length and got stuck - so much so that i had a tough time taking it out.

Since there are many from the set of 35 that I have not used before, I tried out all the bits, and find 4 that had the same problem - won't go in fully, but get stuck. All the rest go in and out like butter. Mind you, the collet was completely loose and i did not touch it from one bit to another.

Both the bits and the collet are 1/2". My router is the Skil 1825, and the bit-set is the Holbren 35.

So have you seen this before? While I am aware the skil is not a great router, it has worked okay functionally, so I am thinking the bits have a bit of a quirk? Is there an easy fix to this?

[LCHIEN]

do you have a set of the $15 HF digital calipers? If you did, it would take you about 10 seconds to determine if the fault lies with the bit shanks or the collet.

Calipers are one of the invaluable tools I have and really cheap and effective at $15.

[radhak]

Unfortunately I don't have the digital one, yet .

I know - the very next purchase...

[sweensdv]

Did you call Holbren and talk to them about this? I think if you did, you'd be very pleasantly surprised at how great their customer service is.

[Joe DeFazio]

I had this problem with a cheap set of bits (The MLCS 15 piece 1/4 in. set), and, after measuring with a digital caliper, I elected to abrade the offending bits down to size. I think I used an extremely fine wet-dry sandpaper, followed by a white plastic pad (sold as a substitute for 0000 steel wool, but finer IMHO).

If you go this route (sorry about the unintentional pun), make *several* measurements of the bit first. I found that some of the shanks were not uniform from top to bottom, or even very slightly elliptical in places. The discrepancies I am referring to were only in the range of .001-.002 inch. It was fairly easy to remove .001 only in the area where the shank needed to be trued.

I would *not* recommend removing material from the whole shank (in other words, don't just wrap the shank in sandpaper or steel wool and twirl away). If you did so, only the new high spots would be grabbed by the collet, which would be an unsafe situation. It is much safer to remove only the high spots, leaving a fairly uniform shank to be grabbed securely by the collet. If I remember correctly, doing around five bits took about two hours, working carefully. All bits have worked well since.

Joe

[Holbren]

If you said you broke the 1/4" straight bit I would say OK, let's make it right but that problem I have never heard of. As Loring said, the caliper will tell the tail. Let me know how you make out so we can figure out the best way to proceed.

[radhak]

I finally got my digital callipers from HF, and measured the shanks. To all purposes it looks like there's no significant difference between the shanks of the problem bits from the other ones. ( I am finding it difficult to get exactly the same reading consistently : with each attempt the reading seems to vary a bit - say by 0.001" !).

I do see that the problem shank seems to show 0.5" more consistently, while the others average 0.499"... Maybe a problem with the way I'm handling the callipers?

Anyway - so y'all were right and i was wrong - the shank's thickness is not the problem .

Then what is? I am tending to believe I might just need to clean the problem bits' shanks - maybe something sticky on it. How do i do that? I don't want to rub lubricants on - dunno, it might not allow a good grip in the collet after that?

Whaddya say?

[LinuxRandal]

Even MINOR differences in Shanks thicknesses, CAN make a difference, if you don't back the collar all the way back. If your collar isn't backed off, it can be squeezing shut, just enough that any spots between the two could stop it.

Also look for rust spots on the inside of your collar.

Do you keep an o-ring on the inside of your collar? (some do this so the bit goes to a consistant depth) If so, is your router flat when placing in the bit, so the ring isn't offset and pinching/restricting the bit setting?

When you say no significant differences, is there paint on those shafts that are giving you trouble?

[LCHIEN]

There some tehniques to the calipers.
+/-.001 on the reading is probably what you'll get.
if you have collet fit problems then they are probably more than .001 over
One, you need to learn to hold the calipers loosely to the shank but with enough force to follow the contour, then rotate the shank. as it turns there may be high spots if you have an oval shank. It's quite common with wooden dowels from the hardware store, often .010 more than the minimum diameter. You should record the readings on shanks as a min/max value to indicate any ovality.

Then you should do the readings at about four or five points up and down the inch long length of the shank... because it may be fat in the middle (esp. since you say it got stuck in the middle).

Post the readings you get on a good shank and a bad shank and then I'll offer comments again.

[radhak]

Even MINOR differences in Shanks thicknesses, CAN make a difference, if you don't back the collar all the way back. If your collar isn't backed off, it can be squeezing shut, just enough that any spots between the two could stop it.

Also look for rust spots on the inside of your collar.

Do you keep an o-ring on the inside of your collar? (some do this so the bit goes to a consistant depth) If so, is your router flat when placing in the bit, so the ring isn't offset and pinching/restricting the bit setting?

When you say no significant differences, is there paint on those shafts that are giving you trouble?

Hmm : rust, and paint - did not look for either specifically, shall do tonight. These are Holbren bits, so the shanks are unpainted, but still...

No, don't use an o-ring, yet. Need to get those.

I do think I had the collar fully backed out, first thought i had.

[jwaterdawg]

A soft brush (toothbrush and/or brass) and rubbing alcohol or mineral spirits can work wonders for cleaning a shank and/or collet.

$0.02

[radhak]

There some tehniques to the calipers.
+/-.001 on the reading is probably what you'll get.
if you have collet fit problems then they are probably more than .001 over
One, you need to learn to hold the calipers loosely to the shank but with enough force to follow the contour, then rotate the shank. as it turns there may be high spots if you have an oval shank. It's quite common with wooden dowels from the hardware store, often .010 more than the minimum diameter. You should record the readings on shanks as a min/max value to indicate any ovality.

Then you should do the readings at about four or five points up and down the inch long length of the shank... because it may be fat in the middle (esp. since you say it got stuck in the middle).

Post the readings you get on a good shank and a bad shank and then I'll offer comments again.

Once again, you have pointed out detailed steps that I had not followed - just took reading(s) at the same spot again and again . Shall do that today and update here. Thanks.

[radhak]

A soft brush (toothbrush and/or brass) and rubbing alcohol or mineral spirits can work wonders for cleaning a shank and/or collet.

$0.02

Duh! simple and intuitive. Shall try that too, thanks.