Drill hole size for hanger bolt?

Hi Bart

Bart Can you explain that in a different way, do you gave to tap thread? , or what, I'm sure You know what the heel of the neck is , but I don't If you have to cut tread, you need a 13/64" drill to tap 1/4" with 20 threads per inch, if you want to have the bold slide in 17/64 would do or else a 6.5 mm if you happen to have metric bits

Have fun and take care Leo Van Der Loo

Bart V wrote:

Hi Bart,

You could take a piece of scrap wood and drill a 9/32" hole and test the bolt in the hole. Alternatively you could use a 5/16" drill and this would be more that sufficient. Do this also in a piece of scrap wood before drilling into your wood turning. If you are sure that your hanger bolt is a true 1/4" you could get clearance with a 17/64" drill if you have one. Use a twist drill and that will give you a clean hole. Be fore you start the drill also use a centre punch and a start point for the drill. Good luck. John

I didn't know what a hanger bolt was until I saw one either :) Ok, it's a two-sided fastener - one side is a regular woodscrew, the other side is a bolt. The end I'm talking about is the woodscrew part, it's 1/4" alright so I need to drill a hole that is smaller than 1/4" else the screw threads cannot bite into the wood as I'm screwing it in. So I guess my question is, how much smaller? My concern of course, too small and the wood of the neck will split, or too big and the screw won't hold. Oh and to be sure, the [banjo] strings will put a ridiculous amount of tension this connection/joint that's why I was wondering about the soaking in oil thing. On a personal note, being able to someday make my own banjo is what I got my lathe for in the first place. Well, that and also to get rid of the pile of wood in the basement I'd been stashing cause them pieces were just too pretty for the fireplace. It's really unbelievable the kinda stuff you can score at a pallet factory's "free firewood" dumpster... My wife is happy that the wood stash in the basement is getting smaller although the mantle is starting to buckle trying to support all them purdy new round thingies ;) Bart. P.S. Leo, zou graag eens met je babbelen

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OK Bart, I have some of those, never heard them called hanger bolds though, come to think of it, we call them WC bout

If I would have to do this, I would get my dial calipers out, measure the outside thread dimension and shaft size, then take a scrap piece and drill a hole that would give me approx., 75% thread depth so lets say the shaft is 6 mm and the outside thread dim. is 10 mm then your difference is 4 mm, then you want 3 mm thread depth, and you drill your hole 7 mm, now screw in your bold, you can saw the thread of your bold so that it will cut tread, that helps, and you could also put some wax on your bold, that helps also, if your wood splits you will have to go bigger with your drill size, 75% thread depth is typical for tapped bolt thread, I don't know if 75% is realistic for a wood screw, that does not tap its thread but forces the wood open, I think that your best bet is to saw the thread on your bold deep enough, like a tread tap, and clamp the wood to prevent it from splitting, turn the bold in and out clean and wax, and turn back in, by then I think you will feel how tight the bold is, make sure you try on a scrap piece that is if not the same at least as hard and solid as the wood your going to use for real, the best I can do for you, good luck. Ik woon in london je can me bellen of e mail me, ok?

Have fun and take care Leo Van Der Loo

Bart V wrote:

Hi Bart,

Are hanger bolts the accepted hardware for what you are making? I think of them as rough & imprecise fasteners more useful for furniture etc. Usually the threads are rolled and the double depths imprecise. They crush the wood rather than cut it.

On Leo's coffee table there is a book that lists drill sizes for specific sizes of bolts, but they refer to metal work. If hanger bolts are what you want, then I think the hole should be the size of the bolt's core and you would best strengthen the wood with dab of ca glue instead of oil. You might want to lube the bolt's threads with soap. (Use Ivory, it's 99.9% pure, while nobody but Leif knows what's in LDD or how it works and he won't tell. 'G')

I am so banjo illiterate (wotttenhell is a pot/rim?) that I don't even know if you want to fasten wood to metal or to wood, but either way I wonder if there aren't better methods than hanger bolts?

Turn to Safety, Arch Fortiter

clearance(?) hole for a wood screw should be the same as the root diameter of the screw

I doubt any kind of surface treatment coul make the wood appreciably stronger

HTH Dale

Normally the threads are cut from the size stock indicated, so they should be a bit higher than 1/4" on the wood screw side, almost 1/4 on the machine screw side. With a full set of bits, you should be able to go 1/16 less and have plenty of hold. I like to sight the shank of the drill versus the body of the bolt for appropriateness.

Don't use soap to lube screws, it's deliquescent, and will promote corrosion. Traditional is wax. Beeswax or paraffin canning wax would work. Oil would soften the area, which is opposite of what you want.

Bart, by all means use traditional wax, it's not the season for deliquescense. :) Soap was a way to tease Leif, our newest COC. Sorry......(not really) BTW, the book on the coffee table belongs to Leo Lichtman, not the Leo from the land of windmills, dikes and wooden shoes..... and gracious people.

I don't know from banjos. What is a pot/rim and what are the turned parts that you are fastening together?

I do think CA glue might strengthen the wooden threads, but I await disagreement. This is serious business. :)

Turn to Safety, Arch Fortiter

Get the Foxfire (II, I think) book off the shelf and learn some banjo other than a toolrest.

I am assuming (yeah, yeah) that he's using the coarse wood thread into the end grain of the wood, the fine, and a washer/nut, through the turned rim. With the deep threads he shouldn't need help, though it's not my banjo.

It seems like such a real long time ago, sigh...

The pot, or drum (the big round part of a banjo that the skin is mounted on), is fastened to the neck with these hanger bolts. There are other ways to fasten it but this is [traditionally] the easiest way of doing it. Yup, I agree, it sure doesn't seem hi-tech but even banjos $5,000 and up are built that way. Of course, they do use nicer looking bolts than the ones from Home Depot... This pot by the way, just looks like a hoop - 11 inch diameter, 5/8" thick, 2 1/2" tall. I made it gluing up 3 segmented layers (2 jatoba,

1 ebony) and pretty much all the steps along the way to get me the finished pot became possible only & totally because of the great and generous advice dished out to this total rookie by all of you great people on this group - take a bow folks, you've more than earned it! Bart. P.S. it'll be a while but I'll post pics when the whole thing is done.

- Check my most up to date email address at:

banjo bridges, tabs, stained glass:

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Thanks for explaining Bart, saves me hunting for my old yellowed & frazzled copy of "Foxfire". I look forward to pictures of your banjo, not sure I want to hear it played tho. Never thought much of that Yalie with his banjo, Rudy Valle'e. Oftimes, rookies outperform experienced players. That includes woodturners. Actually, making the same mistakes for years doesn't constitute experience.

I hasten to include lots of G's, :)'s & TICs.

Turn to Safety, Arch Fortiter

Hi Arch

Wax does really help turning in screws, and soap might be slippery, I would use that on rubber material installing, and yes Ivory snow was the favorite in the car assembly plant, in the days wind shield and back lites were still installed with rubber grommets. The reason I was recommending the 75% tread depth, is that the hard hardwood will not compact like the regular soft or hardwood, and will need some room to expand into, question is how much, and that will be different all the time with different wood I think, so I thought that it would be prudent to go for a trial with a scrap piece. Also the CA glue certainly help with soft and punky wood, but with this very dense wood I don't think it will be much of a help. Now about the banjo, don't know a thing about it , good fun, nothing serious in my opinion.

Have fun and take care Leo Van Der Loo

Arch wrote:

snipped-for-privacy@webtv.net (Arch) wrote in news:14833-41AE11BF-13@storefull-

3176.bay.webtv.net:

Hey Arch, Don't quite have the same amount of experience as you do, but didn't that Yalie (Rudy Valee) play a ukelele? Never did care for singers who sang through their nose (or was that the quality of the records or radio). Always remember Arch, life is just a bowl of cherries, or is it 'life is just a cher of bowlies'? Fond Regards, Hank

Thanks Hank, I think you got it right. I'm wrong again. Not that I would know a ukelele from a bass fiddle. Wonder if they employ hanger bolts.?

Turn to Safety, Arch Fortiter

I drilled some practice holes in the same kind of wood and both 3/16" and 11/64" did a fine job. Since I needed two holes about 3/4" away from each other I decided on the 3/16" just incase the pressure would eventually crack/split the connection - waxed them up and they screwed in nice & tight but easy enough, it feels rock solid. Thanks for all the tips! I installed the fret wire late and the tuning pegs last night and now comes the fun part of assembling the whole thing. Not too sure whether I'm more anxious to find out what it'll sound like or looking forward to slopping the oil on the barewood to finish it... A few more thisses and thats to do but I should be picking & grinning this afternoon :))) Thanks again, Bart.

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banjo bridges, tabs, stained glass:

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Bart

Glad to hear it worked out !!

Have fun and take care Leo Van Der Loo

Bart V wrote:

Actually, life is like a bowl of jalapenos...

What you do today might burn your ass tomorrow..