Hole Size for Belton Sockets

[The New Steve H]

I got Belton sockets for my 6L6 tubes. The site where I got them recommends a 1 3/16" or 1 11/64" hole for each socket. The undersides of the sockets have steps in them. They have one ring about 1.17" in diameter and about 1/16" high. Then they have a ring about 1" in diameter and about 1/4" high.

Question: am I going to regret it if I put them in 1" holes? They'll sit about 1/16" above the metal of the chassis, but I see no reason not to do it. I have lots of easy ways to make 1" holes, but I would have to use a boring tool and a mill to make a 1 3/16" hole. They are secured with two screws, one on each side of the socket.

Link: http://thetubestore.com/belton8st.html

[David Root]

Personally I would not do that. When you tighten the mounting screws the mounting flange will bend and could stress the pins. Would look like s**t too.

Could work if you find a nut the right thickness but would still look like s**t IMHO.

Do it right. You can buy a cheap step drill bit with 1 3/16 on it, that's what I did, cost $25 IIRC. Much cheaper than a Greenlee punch, which is really the best way to do it.

[NickC]

I recommend using a Greenlee punch for holes that large (but I'm not sure which of the two sizes mentioned is best in this instance).

[ToneMerc]

Question: am I going to regret it if I put them in 1" holes? They'll sit about 1/16" above the metal of the chassis, but I see no reason not to do it.

Well, do you want it to look professional or just cobbled together? You should just get the larger size step bit, that's what I've used to enlarge holes for the Belton octal socket.

TM

[tubeswell]

I've used 1" holes for these for a number of amps, and spacer nuts to hold the flange off the chassis (one nut). I could use easily use 1 1/16" since I have about a dozen greenlee punches in all the sizes between 1/2" and 1 1/18". (I don't think it necessarily has to look like what colossal thinks it looks like. ) Its just a different way of looking at the design. (A 'deconstructionist' look) YMMV

[The New Steve H]

Once again, I am surprised to learn that a question I asked was not totally stupid. I completely forgot about the fact that the flange would deform when the screws were tightened. If I had bored 1" holes, I'd have problems now.

As luck would have it, my local Ace Hardware had a hole saw in 1 3/16", so I'm all set.

I went to the hardware store figuring they might have a spade bit I could use. I could make a shallow 1 3/16" hole and then go the rest of the way with a 1" Forstner bit. But a hole saw will do the whole job.

A unibit is a great idea, but the steps are short, and I would have to drive a long way to get one in 1 3/16".

I should have pointed out that this is a 3/8"-thick chassis, so a punch is not a great option.

[ToneMerc]

I should have pointed out that this is a 3/8"-thick chassis, so a punch is not a great option.

Hmmm, 3/8" really? Now I see why you mentioned a boring tool. I was trying to figure out why you would need a boring tool for such thin stock. I think you will find other issues in that the socket pins will literally be recessed into the chassis.

TM

[The New Steve H]

Already looking forward to that. Maybe next time I'll do it the easy way. Probably not, though.

[ToneMerc]

The pwr socket base will be recessed about .040 in the hole. It's around .480 from the mounting flange to the base of the bottom most hole of the socket pin. In some conditions .100 is a plenty to work with, here it's going to be little tight so be cautious concering shorts to ground.

However; if you are using the Belden 9 pin, the distance from the mounting flange to the very tip of the socket pin is only around .395. Thus, it's going to be real interesting when you go wire heaters, attach grid rsistors or snubbers.

You are a glutton for punishment

good luck

TM

[The New Steve H]

I saved like $40 though! Exciting, right? RIGHT?

[M Fowler]

I have a high grade hole saw kit, Greenlee knockout kit and step bits.

None of those correctly size the hole needed for the belton's. One of these days I plan to measure all this stuff and buy correct punches.

The problem with hole saw kits and knockout kits is they are designed for different applications such as plumbing (water pipe size) and/or (electrical conduit).

The correct size means buying a single punch of the correct diameter which I didn't know until after spending lots of dollars.

Mark

[Phil_S]

As luck would have it, my local Ace Hardware had a hole saw in 1 3/16", so I'm all set.

I humbly disagree. It is my experience that a hole saw is the least accurate, most difficult to control of all the options. I suggest this is not the right tool for the job and you will not be happy with the hole. If you are able to test it on something, you will find the answer without ruining a good chassis. Just my 2 cents.

[The New Steve H]

Okay, here is the wisdom I have gleaned from this experience.

1. An Ace Hardware 1 3/16" saw will make a usable socket hole in 3/8" aluminum, and the flange on the socket will cover a pretty hideous error.

2. When using a hole saw on thick aluminum, it's not the time to say, "Screw the lubricant; this will only take a second." You should have heard my drill press scream.

3. If you are crazy enough to do this, use a unibit first to make a hole for the 1/4" guide drill on the hole saw.

4. The socket base on the Belton socket is plenty deep to give you access to the solder lugs. I would say the aluminum only goes about one millimeter past the plastic.

5. Wood screws and an impact driver work great on thick aluminum, if you coat the screws with beeswax before forcing them into the metal. This will be helpful for idiots who drill too close to the wall of the aluminum channel (even though they considered this before situating the holes) making the use of nuts impossible. Not that I know anyone that stupid. As far as anyone can prove.

6. Drill the little holes for the mounting screws AFTER you make the big hole. I got lucky in spite of not doing this.

7. A drill press is not rigid enough to make a hole saw work without a guide bit. Enough said about that.

It actually worked. The socket looks like it grew there. There is some gouging around it obtained during the learning process, but the flange covers it completely.

A Forstner bit and WD40 would have worked a lot better, but the closest thing I had was 1 1/8". A unibit would have left a ridge of metal around the bottom of the hole, unless the steps were long enough to punch through.

I have machine screws on the base of the choke, but I think I'll just replace them with wood screws. They seem to work great, and there will be no crap hanging off the bottom of the channel to get in the way.

Thanks for the help.

[Noval_novice]

Yup, I think I have learned some painfully similar lessons about hole saws.

[David Root]

The step bit generally leaves a partial or whole thin ridge around the inside of the hole. In aluminum or steel, this can be taken care of with a wood carving crookleg micro chisel and a suitable smaller hammer. See pic.

They have very hard steel. I have been using one for about three years now to clean these holes up. Get the chisel dead flat with the chassis face and it won't dig in.

Forstner bits work in aluminum but NOT in steel! Forget about hole saws, that's a construction tool.