25th Feb 2017, 06:24 PM #1
Are you sure 19mm is right for a 3/4 bench dog?
The Timbecon website and everything I've read says a 19mm hole is fine for 3/4" bench dogs, but mine are getting jammed in tight, requiring pliers to extract them from the workbench.
The workbench is a work in progress.
Using the Veritas bench dogs, and they slide in nice till widest part of the spring wire then have to mallet it in, which I expect but not that much!
I'm using a 19mm Forstner bit on a drill press, the bench top is 90mm thick.
I've smeared the dog with beeswax polish. but that does nothing for the spring and the main body of the dog was sliding in fine.
This is as far as I can push it down by hand:
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25th Feb 2017, 06:51 PM #2
3/4" is 19.05mm. It shouldn't be that tight. Check the diameter of the dog. They might be oversize. The dog should be just under 3/4". Veritas bench dogs are 0.74" which is 18.796mm.Those were the droids I was looking for.
25th Feb 2017, 07:17 PM #3
The dog is 18.8mm - it's the spring that's the problem; maybe I can use a Dremel sanding drum and just open the top of the hole a bit.
25th Feb 2017, 08:23 PM #4
How accurate is the hole diameter?
Try easing the hole out a little by wrapping sandpaper around a dowel; the closer the fit the better.Nothing succeeds like a budgie without a beak.
25th Feb 2017, 08:36 PM #5
I drilled real 3/4" holes in my bench for Veritas dogs and they are tight and sometimes need a tap from underneath to get them moving. The spring has also worn a bit of a groove in the most used holes which is a slight annoyance if I want to set the dog just a little off square. I have also used square timber dogs with a spring leaf in another old style bench and they had a sloppy fit that caused no issue when the vise was closed up. I've been considering enlarging my holes so the Veritas dogs are a bit looser in the holes, but still snug enough for the spring to hold them without being under load.Franklin
25th Feb 2017, 08:37 PM #6GOLD MEMBER
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Check the drill bit diameter by measuring the hole that it drills. It's not uncommon to find any type of drill bit that drills a hole size vastly different to what it should be.
26th Feb 2017, 10:48 AM #7
It's a pine top so the dogs should ware in soon. The spring will also ease up a bit with use. Using a dowel as a punch and a mallet drive them dogies right through a few times. If that does not work then as Chief Tiff says get the sandpaper out but dont go hog wild and make the holes too large.
26th Feb 2017, 04:49 PM #8
I have the Veritas bench dogs. They work with a 3/4" hole (in European Oak) ... which may be a tad larger as I used a brace.
Can you try it with the spring removed?
If this works, can you flatten the spring a little?
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
5th Mar 2017, 08:46 AM #9
Nat, as others have said, drill bits do vary quite a lot, though we're talking less than a percent of nominal diameter, so that is less likely to be the primary problem. As Derek has alluded to, drilled holes turn out differently in different materials, and I reckon that's likely to be the source of your woes. A Forstner bit will give almost as clean a hole in softwoods as in hardwoods, but auger & twist bits will produce slightly ragged holes due to torn rather than severed fibres, and you'll also get more spring-back of material pushed aside rather than cut by the bit. Judging by the edges of the hole on your pic, it isn't a super-clean hole, so I'm thinking that's what you need to work on. I'd certainly try cleaning the holes up a little as a first line of attack. Make a couple of holes in some scrap of the same material or similar, to experiment on. My first line of attack would be to chuck a 19mm twist or brad-point bit in a battery drill and spin it at the highest speed whilst raising it up & down. You could lean it a bit in a circular fashion to ease the entry a bit, but go cautiously with that, it's too easy to catch the lands and tear out an unsightly chunk. If that works, you can then proceed to clean out the bench holes to get the desired fit. The difference between an interference fit and a sloppy fit is quite a bit more in wood than with metal, but still often less than you expect.
I have not had any experience with the Veritas dogs so this is just opinion, but I would expect you have a fair bit of leeway with the hole size. I use square wooden dogs, and to make them stay put, I've fitted each with a 10mm ball catch. Being wood, the dogs need to be comfortably under-sized to cater for annual wood movement, and there isn't a huge amount of useable travel in a ball-catch, so I was expecting my system would not be terribly durable. However, many years down the track, and although the balls have worn slight indentations on the sides of the dog-holes, they all still work perfectly. It looks to me like the springs of the Veritas dogs have quite a bit more useable travel than a ball catch, so even after allowing for the softer pine bench material, they should be okay in slightly oversize holes, & go on holding for a tolerably long time.
If you do get excessive wear, it shouldn't be too big a hassle to replace that section of your bench with a hardwood strip for dog holes, but maybe you'll decide to build a nice new hardwood bench, sooner rather than later. Most of us old-stagers have been through a few benches in our times.......
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