12" Cab Diary Continued

[funkle]

I’ve just realised that there are no Speakon connectors in the parts list, either....perhaps they come with the crossover kit, though? 

[LukeFRC]

1 hour ago, funkle said:

I’ve just realised that there are no Speakon connectors in the parts list, either....perhaps they come with the crossover kit, though? 

Think so, Stevies sorting that I think.

 

i ordered from blue Arran at the weekend as one of the choices of tuffcab had a two month wait... a large box turned up today! So that’s exciting. 

 

[funkle]

Good morning all

Ok, I have some specific questions reading through the build process/photos. Perhaps other may have good answers to these questions.

 

1. Installing T-nuts. I have now watched a few videos on this, including this one (https://www.youtube.com/watch?v=HVfkxJiqLkA). However, it seems clear that getting a good straight hole at 90 degrees to the face of the plywood they are being installed into is key to having them work well.

Since I don't have a drill press, does anyone have any tips on how to get perpendicular 90 degree holes with a handheld drill? I have seen a few videos with some ideas, but they all need you to make your own guide or jig, often using other tools I don't have. I'm interested to know if there is a tool that I can buy to help make this easier. 

 

2. I should have asked before I ordered some screws (lol), but is there a guide for how long a screw should be for the 15mm plywood being used? For instance, for installing the handle, or the crossover. I'm debating using T-nuts for the handle, but will see how the screws look when I get them.

 

3. Are washers necessary for the correct installation of T-nuts? If so, we should probably add to our parts list.

 

4. When fitting the port tube, does the port tube need to be glued into place at the baffle end, or is it simply a compression fit?

 

5. Are there any requirements for the paint that goes inside the port tube, or can I just paint it with matt black paint that I'm going to use for the baffle?

 

 

Thanks in advance. I think I'll post up some detailed pics when I do my build (in the other thread I have created), and make sure that I document anything that seems trickier. It may help others who come after. 

Pete

Edited August 10, 2019 by funkle

[funkle]

Ok. Answered one of my own questions. I found some small guides to try and allow the drilling of right angled holes perfectly. For both it seems advisable to clamp the guide in before drilling. 

https://www.amazon.co.uk/wolfcraft-4685000-Mobile-Drilling-aid/dp/B001154WTS

Or

https://www.amazon.co.uk/Big-Gator-Tools-MDG1000NP-V-Drill/dp/B00CYNOFM0

 

Edited August 10, 2019 by funkle

[tauzero]

On the purchasing front, had Stevie got something lined up for bulk purchase of drivers at a reduced price, or am I imagining it?

[LukeFRC]

9 hours ago, funkle said:

Good morning all

Ok, I have some specific questions reading through the build process/photos. Perhaps other may have good answers to these questions.

 

1. Installing T-nuts. I have now watched a few videos on this, including this one (https://www.youtube.com/watch?v=HVfkxJiqLkA). However, it seems clear that getting a good straight hole at 90 degrees to the face of the plywood they are being installed into is key to having them work well.

Since I don't have a drill press, does anyone have any tips on how to get perpendicular 90 degree holes with a handheld drill? I have seen a few videos with some ideas, but they all need you to make your own guide or jig, often using other tools I don't have. I'm interested to know if there is a tool that I can buy to help make this easier. 

 

2. I should have asked before I ordered some screws (lol), but is there a guide for how long a screw should be for the 15mm plywood being used? For instance, for installing the handle, or the crossover. I'm debating using T-nuts for the handle, but will see how the screws look when I get them.

 

3. Are washers necessary for the correct installation of T-nuts? If so, we should probably add to our parts list.

 

4. When fitting the port tube, does the port tube need to be glued into place at the baffle end, or is it simply a compression fit?

 

5. Are there any requirements for the paint that goes inside the port tube, or can I just paint it with matt black paint that I'm going to use for the baffle?

 

 

Thanks in advance. I think I'll post up some detailed pics when I do my build (in the other thread I have created), and make sure that I document anything that seems trickier. It may help others who come after. 

Pete

I might be wrong but I think the bolts for the speaker can do the feet too. Not sure about the handle as I think they will look a bit proud of the top. 

According to the plans isn’t there a support ring for the handle! So you’ve got something (screws or bolts with t nuts going into 30mm of ply.)

i don’t think you will need washers, I’ve not seen them used in other builds.

Painting a port tube... see if the Matt black paint you’ve got will stick to plastic... you may have to lightly sand the plastic to give it something to key onto. 

And - I’ve not used t nuts at all but used threaded inserts which similarly need a straight drill ... but managed by hand... 

[LukeFRC]

5 minutes ago, tauzero said:

On the purchasing front, had Stevie got something lined up for bulk purchase of drivers at a reduced price, or am I imagining it?

For the HF driver yes, which you can buy via him as Celestion are really supportive.

 I think he said Blue Arran weren’t budging on price for the Faital driver. 

[funkle]

57 minutes ago, LukeFRC said:

I might be wrong but I think the bolts for the speaker can do the feet too. Not sure about the handle as I think they will look a bit proud of the top. 

According to the plans isn’t there a support ring for the handle! So you’ve got something (screws or bolts with t nuts going into 30mm of ply.)

i don’t think you will need washers, I’ve not seen them used in other builds.

Painting a port tube... see if the Matt black paint you’ve got will stick to plastic... you may have to lightly sand the plastic to give it something to key onto. 

And - I’ve not used t nuts at all but used threaded inserts which similarly need a straight drill ... but managed by hand... 

I think, on reflection, I'll stick to the T nuts and bolts for just the horn/compression driver and the main woofer. It's probably overkill on the handle and feet. I bought one of the tools I linked to above make sure I drill the holes for those properly at 90 degrees. It seems silly to ruin a baffle by screwing up a T nut install...I assume most manufacturers use wood screws because of the faff involved with T nuts, though the latter seem much more sound. 

I just double checked the plans. They definitely do have a supporting brace for the handle. 

Glad we likely don't need washers. I'll make sure I just have a single one for helping to install the T nuts - when you tighten bolts to help seat the T nuts in, it's helpful to have a washer while you tighten the bolt, to avoid damage to the facing wood, apparently.

Until I hear more from @stevie, I'll plan that the port tubing gets glued in at the baffle end, rather than just compression fit.

 

[tauzero]

If you use flanged bolts, you don't need washers anyway.

[funkle]

3 hours ago, tauzero said:

If you use flanged bolts, you don't need washers anyway.

The bolts on the parts list are not flanged. However it seems like it may not matter for this application anyway...?

[Chienmortbb]

On 10/08/2019 at 15:04, funkle said:

Ok. Answered one of my own questions. I found some small guides to try and allow the drilling of right angled holes perfectly. For both it seems advisable to clamp the guide in before drilling. 

https://www.amazon.co.uk/wolfcraft-4685000-Mobile-Drilling-aid/dp/B001154WTS

Or

https://www.amazon.co.uk/Big-Gator-Tools-MDG1000NP-V-Drill/dp/B00CYNOFM0

 

I have always liked the look of this https://www.axminster.co.uk/axminster-drill-guide-500458

[Phil Starr]

The drill guides are excellent, I use them when drilling for dowels, or anything where a right angle is critical. I shouldn't say this as I live just outside Axminster but other people do similar guides. Axminster power tools do a bit of quality control though so theirs will definitely be ok.

[funkle]

I ended up going with this one after many rave YouTube reviews - it has arrived and feels like the biz. I’ve seen people now use it without a clamp as well as with, but it’s obviously safer to clamp it down.

https://www.amazon.co.uk/Big-Gator-Tools-MDG1000NP-V-Drill

Edited August 11, 2019 by funkle

[LukeFRC]

1 hour ago, funkle said:

I ended up going with this one after many rave YouTube reviews - it has arrived and feels like the biz. I’ve seen people now use it without a clamp as well as with, but it’s obviously safer to clamp it down.

https://www.amazon.co.uk/Big-Gator-Tools-MDG1000NP-V-Drill

I feel a bit guilty about the fact I ended up buying a freestanding drill press on Friday off ebay... I bought it for the Stairways project I'm doing but it's good to see it might have other uses!

[stevie]

Back from my break. I'll take the queries in date order.

The rollers Blue Aran sell are the same as the ones you can buy in most DIY stores. To get the stippled finish, use the foam roller.

On the matter of costs, the cab is going to be less expensive to build if you already have tools and bits and pieces in your workshop.  I expect quite a few people already have some matt black paint, wood filler, wood glue etc. in a cupboard that they can take out and use. If you have to go out and buy a drill and paint brushes, for example, the cost will go up.

Nevertheless, if you could buy a cab like this one in a shop, it would cost at least twice what you can build it for. 

Thanks for bringing up the question of screws. There are actually quite a few different types of screw needed and I haven't really provided much info on that.

For the main driver and horn, I'd suggest black 25mm M5 machine screws into t-nuts. The parts list says hex machine screws, which are great for the main driver, but look pants on the horn. So it's probably better to standardise on M5 pan head, Philips or pozidrive machine screws, 25mm long.

The t-nuts need to be the smaller type. There isn't enough space for the large ones behind the horn. I've heard good things about the threaded inserts mentioned by Luke, and they could work for the horn - but I've no experience of them personally.

I'd suggest flange headed screws for the feet. No. 10 size (I'll check on it) 25mm, although you could also use the same machine screws and t-nuts used for the main driver and horn.

The four central screws for the handle can be normal woodscrews, say 25mm long. However, when you lift the cab, all the weight is on the central handle, and  that is attached to the top of the cabinet with another four screws. I don't see a problem with using woodscrews here also, but some people might be happier using four t-nuts behind the handle. The machine screws would have to be about 40mm long because of the thickness of the handle support. Then you have the problem of getting all eight screws to look the same.

If you've bought the Chinese corners I recommended a while back, you'll already have the screws needed for those. If not, you'll need screws for your corners depending on which corner you're using.

You'll need M6 two hex head bolts to fit the compression driver to the horn - about 15mm long, but I'll check and confirm. Finally, you'll need four small self-tapping woodscrews, 25mm long for the Speakons. I'm not sure of the size, but I'll do some research.

That's an awful lot of screws to source. I'll see if I can put together a screw pack to save everyone a lot of time and trouble.

Edited August 13, 2019 by stevie

[stevie]

The Speakons are included in the crossover and wiring kit.

There's no need to worry about drilling vertical holes, as all the holes have been predrilled in the kit. They're a standard sized pilot hole, which is good for woodscrews but will need to be drilled to size for t-nuts. You'll have to drill holes for the feet, as it didn't make any sense to pre-drill those.

I wouldn't use the method of installing t-nuts shown in that Youtube video because you'll deform the front of the baffle - bear in mind that poplar is a relatively soft wood. It's actually a lot easier to tap them in with a hammer before assembling the cab.

The hole for the port tube is being cut to within half a milimetre to provide a friction fit. So make sure you fit it before you glue the baffle in because it takes ages to fit from the front. There's no harm sealing the port tube from the rear with some glue or silicone.

To paint the port tube, there are a number of spray paints designed for painting plastics which cost between six and eight pounds a can. I used a paint designed for spraying car bumpers because I had some in my workshop. It's quite likely that something else would work, and I'll carry out a few experiments this week. It would be ideal if we could use the Tuff Cab paint. I'll check.

I obtained a generous discount from Celestion on the compression drivers, as Luke mentioned. I'm not going to mention the price on list because it's more than just a few percent.

[funkle]

Thanks Stevie. Hmm, perhaps I should have waited on getting the screws/T-nuts etc - I've messed up pretty much everything in terms of lengths etc, and the ones I ordered from the parts list we have aren't in keeping with what you listed above. Thankfully, 'tis but the work of a moment to sort out returns to Blue Aran. I'll find a use for the other screws.

I'm definitely down for a screw pack, though. Lol

[stevie]

Sorry Pete - that's what you get for being first out of the blocks. 🙂

I'll try to sort the screw situation out as soon as I can and include the recommended types in the parts list. I imagine it's a bit confusing at the moment. To compensate for your mis-purchases,  I'll send you some screws for the feet and handle when I send your kit off (shouldn't be too long now) , as I have some spares. If you need any more M5 t-nuts, I also have spares and can send you some of those too.

Black screws are a pain to source in small quantities. As a temporary measure, you can use normal chrome-plated screws from B&Q etc. and just paint them with car touch-up or whatever you have once they're screwed in. They look all right behind a baffle.

 

Edited August 13, 2019 by stevie

[LukeFRC]

Aw are the screws on the list wrong then? 

[stewblack]

We still have a hardware store where you can buy screws and bolts individually! In a brown paper bag! Sometimes living in the past is quite handy

[LukeFRC]

2 minutes ago, stewblack said:

We still have a hardware store where you can buy screws and bolts individually! In a brown paper bag! Sometimes living in the past is quite handy

So do we, but I’m not sure about black ones

[LukeFRC]

47 minutes ago, funkle said:

the ones I ordered from the parts list we have aren't in keeping with what you listed above

The ones I got from blue Arran were the 30mm hex screws - they should be good for the main driver. Even if @stevie said 25mm you’re only a hacksaw cut away from there...

[stevie]

36 minutes ago, LukeFRC said:

Aw are the screws on the list wrong then? 

No, the screws in the parts list are fine. I only listed t-nuts and 30mm machine screws in the parts list and they are perfectly all right for the main chassis. If you want to use t-nuts on the horn, however, the hex heads won't look great. So you can either use black wood screws (without any t-nuts) or pan headed machine screws and t-nuts.

The lengths I suggested above are nominal and 30mm (or even 40mm) is OK.

[LukeFRC]

5 minutes ago, stevie said:

No, the screws in the parts list are fine. I only listed t-nuts and 30mm machine screws in the parts list and they are perfectly all right for the main chassis. If you want to use t-nuts on the horn, however, the hex heads won't look great. So you can either use black wood screws (without any t-nuts) or pan headed machine screws and t-nuts.

The lengths I suggested above are nominal and 30mm (or even 40mm) is OK.

Cool  I probably have more than I need then but they aren’t all wasted! 

[funkle]

@stevie thanks for your suggestions and work. I don’t mind being an early adopter, we’ll help work some of the kinks out of the process for those who follow. I really appreciate your offer of the extra fasteners of various sorts. 

This is going to be a belter of a cab. I estimate I’ll be in for about £470 after everything is paid for (including tools I had to buy), but it’s still much cheaper than the nearest equivalent boutique cabs, either new or secondhand.

(A Fearless F112 is around £750-800 new/£500 used and weighs more; a Big Baby 2 is £780 new/£550 used and is a bigger cab. The Audiokinesis Thunderchild or Hathor are the other main USA competitors and similarly expensive once shipping and duties are accounted for.)