Pop quiz, spot what the issue is... and the fix

[Ttrees]

I got a bit enthusiastic whilst drilling some holes for this vise installation.
However I only made my mind up that I would prefer these nuts to be flush
I might likely make them a bit skinnier with the bench grinder and some filing.
Could even lap them if I wanted on a lap, or on my cheap diamond hones, as would make a nice job of the nuts, but won't be polishing them.

Plenty of suitable drill bits I have, both really cheap ones like that wide bit, and dear ones,
but only drilled the holes to accept M10 thread,
all went well with the drilling with no breakout or anything,
But.. for a few minuets, I was not happy!

Luckily the fix exists, well I hope so at least, and if not, likely will be great with a little work.
I'll be making a timber spacer for this soon, it's not got anything to do with the job.

What did I do wrong?
What is the fix evident in the photos?

 

[Ttrees]

Anyone?
Perhaps some more clues might do the trick

 

[Terrytpot]

The only issue evident is a spade bit isn’t much use at enlarging an existing drilled hole as it can no longer align itself with the centre of the hole as it’s not there anymore…which if you’re wanting to have the nuts flush “ish” presents an issue if that 20mm spade bit is the only one you have capable of enlarging a hole for accepting the nut in a recess.

 

[Ttrees]

@Terrytpot
The sleeves I was pleased to have found, is the fix for the existing drilled holes.

 

[Terrytpot]

@Terrytpot
The sleeves I was pleased to have found, is the fix for the existing drilled holes.

Taping a thread in them?

 

[Ttrees]

Maybe this might give it away.
The M10 threaded bar and fixings shown are the only thing involved,
and you are correct on the nuts being flush (which I might slim down on the ginder and maybe a tack with the welder)
Though the relative depth isn't important, although the fact that it can be done fairly nicely.

 

[Ttrees]

Perhaps I need to show the results that it makes?

 

[Ttrees]

Will this explain it?

 

[Ttrees]

On a different note...
One way of getting a good result cutting threadbar

 

[Ttrees]

I think you'll agree, an outstanding result from a wonky poundshop spade bit.

Left a burr on this lab countertop, but leaves clean holes in timber.
Could think about some sort of depth stop as its a trial and error thing, and easy to over do it,
so one must be careful!

 

[--Tom--]

Guessing the error was drilling the hole for the thread before the hole for the nuts?

 

[Ttrees]

@--Tom-- Kinda, but the sleeve/bushing was the fix for that, which was improved with a bit of insulation tape for a tighter fit.

 

[throbscottle]

I'm really confused about what has happened here, please help me understand!
So what I see is, you drilled holes in a metal table, which then turns out to be plastic (can't tell from 1st pic)
You realised you needed to counterbore the holes so some nuts could be hidden in them
Fitted a sleeve to the shank of the wonky poundshop spade bit, then fitted a sleeve in the holes you drilled
Then magically, the counterbores appear! How the heck did that happen? Is it that the sleeve just fits the spur of the bit? Is it? is it????? (gnashes fingernails from the stress of not knowing...)

Potentially you could alternatively grind a wonky poundshop spade bit into a wonky poundshop counterbore spade bit, so instead of a spur it has a long wide section that fits in the pre-existing hole, and the blades could be ground level so you don't get a hump in the hole. Though it might need a half-round dowel gluing to either side for stability.

Now I have to get some wonky poundshop spade bits to try the experiment!

Nice job anyway. I've made the same mistake a few times myself - well done!

 

[Ttrees]

@throbscottle the spur of the spade bit isn't involved!,
and no sort of plug was used to drill the wider holes.
The sleeve was only the fix for my numpty move of drilling to final size before thinking,
Must say though possibly a likely improvement for something thinner than say an inch.

So only the spade bit and the sleeve was used, and nothing else involved in the process of countersinking these holes apart from the hole drilled previously.
The sleeve is the giveaway.
One might even question why these bits aren't made like this in the first place?

 

[xy mosian]

Did you 'sharpen' the rear end, shoulders, of the flat bit? Passing that through the sleeve in the hole before chucking in the drill. It would be tempting to assume a need to dun the drill backwards, but the bit could be sharpened to cut when run in reverse.
gf

 

[Ttrees]

Spot on @xy mosian
Not being sure of what direction was best, but I filed the bevels right or wrong, so
as the cut was in reverse as it just seemed more suiting

These cheap ones cut like butter with a hacksaw, although you want an aggressive file for
shaping, as in double cut and not a single cut as it will skate about.

I didn't come up with the idea, Frank Ford of frets.com is where it came from,
which somehow hasn't been popularized as it works great.

 

[Setch]

Everyone should should read frets.com. Even if you have no interest in instrument repair Frank is a master at practical problem solving.

 

[xy mosian]

Those flat bits are very useful. Want a small tapered hole, re-file a flat bit, need an odd sized hole, re-file a flat bit. I have converted a flat bit to a tap in the past, not a quick job but quicker than trying to find a suitable tap, and much cheaper for a job of one or two threaded holes.
geoff.

 

[Dave Moore]

On a different note...
One way of getting a good result cutting threadbar
View attachment 137719

Better to cut the other side of the nut, wind the nut on a little after the cut an either file or grind a small chamfer on the end to take off the sharp edge. Then wind the nut off and the nut will cut any burr off leaving it easy to get nut on or off.

 

[Ttrees]

@Dave Moore Don't know how you're doing it, but I have yet to see a better way for short fixings
which is as easy to get everything the same.
i.e the section in the vise is cut to length, not the rest to the left which I presume you were referring to.
Edit: it does look that way in my picture, as it might appear that I'm a left handed sawer!
here is a previous one, the difference in the above one is the nut can be set for the depth of cut, so one can cut where they want rather than
picking a thread.
You kinda still have to, but the fact the rod can be rotated with left hand means you can still cut where you want to.

All the best
Tom