How to slightly enlarge a bench dog hole

[scritch]

I made a workbench from some gluelams I got for free. It is quite
substantial, being about 5 inches thick; very solid. I drilled some
bench dog holes in it, and then I bought a holdfast.

Unfortunately, even though the holdfast was described as 3/4" diameter,
it's really a bit larger, and I need to enlarge the dog holes by about
1/8". I saw one technique where you grind the shoulders of a spade bit
at 60 degrees and proceed carefully down the holes to enlarge them.
Does anyone have better ideas?

Also, I initially drilled too many holes. Any thoughts on plugging
them? I might just glue in some dowels, but someone might have a more
elegant idea.

Thanks,

scritch

[dpb]

On 10/12/2013 11:27 AM, scritch wrote:
...

> ... I need to enlarge the dog holes by about

> 1/8". I saw one technique where you grind the shoulders of a spade bit
> at 60 degrees and proceed carefully down the holes to enlarge them. Does
> anyone have better ideas?

I'd use a twist drill (carefully) -- it'll follow the existing holes
more readily than the spade bit will.

Or, the really clean way would be to glue in a waste dowel and redrill
as wanted w/ a Forstner.

> Also, I initially drilled too many holes. Any thoughts on plugging them?
> I might just glue in some dowels, but someone might have a more elegant
> idea.

...

Use a dowel for the bulk but cut some matching grain plugs 1/4" thick or
so to mate up with the surface if want the appearances...

--

[WW]

"scritch" wrote in message news:l3bt9l$o1g$1...@speranza.aioe.org...

I would plug the holes with a dowel and then redrill with the proper sized
fostner bit WW

[Gordon Shumway]

On Sat, 12 Oct 2013 09:27:38 -0700, scritch <goo...@floober.com>
wrote:

>I made a workbench from some gluelams I got for free. It is quite
>substantial, being about 5 inches thick; very solid. I drilled some
>bench dog holes in it, and then I bought a holdfast.
>
>Unfortunately, even though the holdfast was described as 3/4" diameter,
>it's really a bit larger, and I need to enlarge the dog holes by about
>1/8". I saw one technique where you grind the shoulders of a spade bit
>at 60 degrees and proceed carefully down the holes to enlarge them.
>Does anyone have better ideas?

I'd use a twist bit and take it slow like dpb suggested. Or if you
want to use a Forstner bit drill the desired hole size in a piece of
scrap and then clamp it to your bench to be the guide for the Forstner
bit to get it started. After you get deep enough you will no longer
need the guide and it can be discarded.

>
>Also, I initially drilled too many holes. Any thoughts on plugging
>them? I might just glue in some dowels, but someone might have a more
>elegant idea.

This is an easy fix! Go to Harbor Freight and get one of their
recently inventoried "Negative Kerf" drill bits. They're fantastic!!
:-)


>
>Thanks,
>
>scritch

[woodchucker]

Return the holdfast, buy one from gramercy. I have 2 and love them.

--
Jeff

[no...@none.com]

On Sat, 12 Oct 2013 09:27:38 -0700, scritch <goo...@floober.com>

>Unfortunately, even though the holdfast was described as 3/4" diameter,
>it's really a bit larger, and I need to enlarge the dog holes by about
>1/8". I saw one technique where you grind the shoulders of a spade bit
>at 60 degrees and proceed carefully down the holes to enlarge them.
>Does anyone have better ideas?

You might use an "Oops" arbor with two hole saws.. Lee Valley Tools
sells them. I'm not sure that a 1/8" difference is enough to use
smaller to larger hole saws, but you could visit an LV store and find
out.

http://www.leevalley.com/en/wood/page.aspx?p=52518&cat=1,180,42316

[dadiOH]

"scritch" <goo...@floober.com> wrote in message
news:l3bt9l$o1g$1...@speranza.aioe.org

> I made a workbench from some gluelams I got for free. It
> is quite substantial, being about 5 inches thick; very
> solid. I drilled some bench dog holes in it, and then I
> bought a holdfast.
> Unfortunately, even though the holdfast was described as
> 3/4" diameter, it's really a bit larger, and I need to
> enlarge the dog holes by about 1/8". I saw one technique
> where you grind the shoulders of a spade bit at 60
> degrees and proceed carefully down the holes to enlarge
> them. Does anyone have better ideas?

No idea if it is better but if you don't want to enlarge the holes, shrink
the holdfast. You could take it to a machine shop or if you have something
you can chuck it in - lathe, drill press, etc. - you could do it yourself
with a stone.

Personally, I'd send it back. If they say 3/4 I expect 3/4.

> Also, I initially drilled too many holes. Any thoughts
> on plugging them? I might just glue in some dowels, but
> someone might have a more elegant idea.

You could get some epoxy, thicken it with talc (so it will be white/grey and
opaque) and swirl in different colors. Personally, I'd just use the dowels
:)

--

dadiOH
____________________________

Winters getting colder? Tired of the rat race?
Taxes out of hand? Maybe just ready for a change?
Check it out... http://www.floridaloghouse.net

[Michael]

I would use the drill press to drill the proper sized holes in a substantial piece of hardwood. Then I'd clamp that hardwood to the proper position above the old holes and use it as a guide to enlarge the holes.

Mike

[Lew Hodgett]

---------------------------------------------------------
Return the defective dog(s) and make your own,

Start with 3/4" x 3/4" x 8" maple or white oak piece.

Setup router table with a 3/8" round over bit and fence with stops.

Machine a "dogbone" with 3/4" round in center and 3/4" x 3/4" x 1"
ends.

Cross cut "dogbone" into two (2) equal pieces that become your bench
dogs.

Lew

[BenignBodger]

On 10/12/2013 12:27 PM, scritch wrote:

If the holes are the correct size and the holdfast is too big then you
should be grinding away at the holdfast to make it the correct size (or
return it for one that is correctly sized). Other tools you might acquire
in the future will want the dog holes to be the correct size and there is
no way you are going to shrink them retroactively.

[woodchucker]

Excellent point.

I use dogs from veritas and holdfasts from Garmercy... all fit the same
hole.

--
Jeff

[lektric dan]

I would not permanently glue in dowels. I would make expanding plugs that could be removed. Buy dowels that are snug fit. Cut to length. Drill a hole in the center of one end for a countersunk wood screw. Using a thin kerf saw, cut down the middle of the screwhole (lengthwise) about 1/2 to 1/3 the length of the screw. Insert the dowel in the excess hole, insert screw and tighten. The screw should cause the dowel to expand, securing the dowel in the hole. Might be a good idea to heavily coat the top end of the dowel in parafin or candle wax in case glue or paint gets on it.

On Saturday, October 12, 2013 11:27:38 AM UTC-5, scritch wrote:

[Puckdropper at dot]

scritch <goo...@floober.com> wrote in news:l3bt9l$o1g$1...@speranza.aioe.org:

*snip*

> Also, I initially drilled too many holes. Any thoughts on plugging
> them? I might just glue in some dowels, but someone might have a more
> elegant idea.
>
> Thanks,
>
> scritch
>

If they're not in the way or you're only bothered by the look, I'd consider
leaving them. If you add a vise to your bench, especially one without a
quick adjust, more holes is a good thing.

Puckdropper
--
Make it to fit, don't make it fit.

[k...@attt.bizz]

On Sat, 12 Oct 2013 12:27:27 -0500, Gordon Shumway
<Rho...@Planet.Melmac> wrote:

>On Sat, 12 Oct 2013 09:27:38 -0700, scritch <goo...@floober.com>
>wrote:
>
>>I made a workbench from some gluelams I got for free. It is quite
>>substantial, being about 5 inches thick; very solid. I drilled some
>>bench dog holes in it, and then I bought a holdfast.
>>
>>Unfortunately, even though the holdfast was described as 3/4" diameter,
>>it's really a bit larger, and I need to enlarge the dog holes by about
>>1/8". I saw one technique where you grind the shoulders of a spade bit
>>at 60 degrees and proceed carefully down the holes to enlarge them.
>>Does anyone have better ideas?
>
>I'd use a twist bit and take it slow like dpb suggested. Or if you
>want to use a Forstner bit drill the desired hole size in a piece of
>scrap and then clamp it to your bench to be the guide for the Forstner
>bit to get it started. After you get deep enough you will no longer
>need the guide and it can be discarded.

That's what I would do, even with a twist drill. The hole in the
"guide" scrap can be drilled at the same time. I'd probably use
hardboard for the guide.

>>Also, I initially drilled too many holes. Any thoughts on plugging
>>them? I might just glue in some dowels, but someone might have a more
>>elegant idea.
>
>This is an easy fix! Go to Harbor Freight and get one of their
>recently inventoried "Negative Kerf" drill bits. They're fantastic!!
>:-)

Should have used a portable hole.

https://www.youtube.com/watch?v=dI-I8DQD4LI

[scritch]

Best idea yet! I ordered up two, too. Then, in a flash of inspiration,
I turned a bunch of tapered plugs which I pounded into the holes I don't
think I need. They will make the top smoother and can be tapped out
from below should I need a new hole.

[Jim Weisgram]

On Sat, 12 Oct 2013 09:27:38 -0700, scritch <goo...@floober.com>
wrote:

I made my dog holes with a router and bearing guided router bit. They
ended up perfectly square to the table. You could enlarge an existing
hole by drilling an enlarged hole in a scrap piece and clamp that
scrap over the existing hole, then enlarge with the router. Once the
hole is started, you can go deeper in stages if the router bit is not
long enough.