I would have posted this question here...

Installing ET and BT probes in a Hottop

...but it's an old thread that's no longer accepting posts.

I'm about to install TC's in my HT and need to drill holes in the back plate. I've got my drill and I've got my bit - just looking for advice from people who have done this. Sounds like a number of you have left the plate in place rather than removing it entirely. Advice? Did you leave the HT upright or put it on its back? How did you keep the bit from wandering all over the place? Pretty easy or pretty challenging? I'm sure it would be a much easier job with the plate removed and flat on a bench but if I can successfully drill it while in place, that'll save me a bunch of hassle.

Thanks for any tips!

Dan

I removed the back wall, carefully located where I wanted the probes, used a center punch, carefully drilled both holes, used a tap to thread the back plate, screwed in the probe holders, added a log nut and used high temp locktight to keep it all from moving.

If you have a B2-K model (k-type factory safety temp probe) I would strongly suggest that you just purchase a B2-k + back plate and use the pre-drilled holes for BT and ET probes that are factory located.

I also cut the rear plastic panel and installed panel mount k-type sockets. Much cleaner than just running the cables through a hole.

Otherwise. have fun

Also....

If you do not have the emergency bean dump option, NOW is the time to install it when you have the roaster down to the main chassis plate as you will need to swap out the main chassis plate to accommodate the new hardware

I have a 8828B-2. By emergency bean dump are you referring to a knob on the back of the roaster that you can pull to manually dump the beans? I don't have that. I looked on the HT site to see if I could purchase just that upgrade but either it's not available as a single part upgrade or I'm looking in the wrong place.

Part of the reason I'm going through this process to connect to Artisan rather than purchasing the HT upgrade is to save money so I'm not super excited about dropping another $150+ if that's what it's going to take to implement the emergency bean dump. Just how important is this? Is bean dump failure a common problem after upgrades like I'm doing? Not ideal but I'm guessing worst case I can always just pull the plug?

Yes, the manual eject is the knob on the back. This is useful should you have a power outage during roasting. Just pulling the plug is the same as a power outage. Beans stay inside and if you are near the end of the roast, temp can build up and the beam mass ignite. the older B models with the button thermometer are prone to having the eject button fail (wear out and not eject) have an option to manually dump the roast can be useful when it becomes necessary.

It is not a critical upgrade but the hardest part is getting the roaster broken down to the main chassis (sort of like getting down to the frame on a car, everything has to come off).

You can just drill the back of the roasting chamber and stick in a couple of good quality probes.

You will need the Arduino/TC4 or TC4C but regardless of which board set you decide on if you wish to "control" the roaster from Artisan instead of just "monitoring" the roast you will need to install a HTC interface board, either piggy backed on the TC4/TC4C or as I have done,mounting it inside of the electronics compartment of the toaster then taking the imbecile out to an external TRC4/TC4C.

If you only want to monitor, you can use any of the dual channel data logging meters supported by Artisan. I have used a TMD-56 as an interface between BT/ET probes and Artisan so you are not "shoe horned" into a the TC4 option

Where and how far you go is up to you.

I would recommend you do it all when you have the roaster apart as they are a real b!+h to break down completely.

The complete TC4C+HTC is a nice improvement. You may even want to get the LCD display which will show you BT/ET up front

Yup, I have the TC4C+HTC and super excited about connecting to Artisan! Hope I can get it done today - I've been waiting several weeks for all the parts to come in.

I've been on the HT site and communicating with Randy over there about manual eject. Doesn't seem like there's an option for just implementing that feature - I'd have to buy a whole upgrade kit with parts I don't necessarily want. Wondering if there's a way I can rig something...?

dcoplan wrote:
I've been on the HT site and communicating with Randy over there about manual eject. Doesn't seem like there's an option for just implementing that feature - I'd have to buy a whole upgrade kit with parts I don't necessarily want. Wondering if there's a way I can rig something...?

There was a "home brew" emergency dump build posted on HRO.....

I'll see if I can dig it up and post the URL

EDIT: I believe this is the post - http://forum.homeroasters.org/forum/vie ... post_40019

I too have drilled the back plate, however I did not remove it completely from the roaster.

If you are not careful and patient, the drill bit will indeed drift. I countered that by carefully and slowly starting the hole with the drill running slowly so I could keep it on point. Once enough metal was removed and a divot created, I ran the drill at full-speed.

Be sure to cover your main board below so that metal shavings don't drop on the board and potentially create a short (I used compressed air to clean everything up really well afterwords).

I've done two separate rounds of TC installations, for four total thermocouples. Knowing what I know now, I'd strongly recommend taking the time to remove the plate to install your TCs for two reasons:

1. It's safer/easier to drill the holes.
2. It's much easier and cleaner to apply JB Weld with the back plate lying on a surface. Otherwise the epoxy runs down the back of it and it looks messy and is wasteful.

I too just finished an installation of the HTRI board (TC4+HTC) as well as the two additional probes. You can see my writeup and pictures here:
http://blog.oilslickcoffee.com/2016/03/ ... rol-board/

In the pictures you can see the mess made from applying the epoxy with the plate still installed and up-right. Not ideal and I did find a broken weld that needed attention. Granted, the weld was done five years ago but I don't know when the crack occurred and what affects it had, if any, on roast readings. However, because of the weld-failure, I recommend compression fittings to mount the TCs as Mick, aka Turtle did.

I hope this helps! I think you'll enjoy the new level of control you'll have with the TC4 board.

Very clean install Turtle!

You can pick up a spring loaded punch for <$10 on amazon or elsewhere. That will help prevent the drill bit from wandering.

Also if its not obvious, be sure to install your BT probe where the bean mass is when the drum is tumbling. It should be the clean spot on the back wall from the abrasion.

rama wrote: Very clean install Turtle!

You can pick up a spring loaded punch for <$10 on amazon or elsewhere. That will help prevent the drill bit from wandering.

Thank you for the compliment.

I spent twice the time "thinking" it through than I did actually doing the mods. I find it easier to make changes with pencil and eraser than with a hammer and welder.

I took the back to my bench vice and placed it on the anvil part and used a standard center punch, then opened the jaws and drilled down through the metal between the vice jaws. Nice stable work platform.. Would have been easier if I had a drill press but I have minimal tools as I hate working so if I don't have tools I usually don't have to work

I also drilled smaller so that I could run a tap through the hole to thread it to match the probe compression connectors THEN put a nut on both sides and used a drop of high temp Loctite on the threads to make sure it would never move without a wrench on it.

It has been several years now and the mods are just as rock solid as they day I did them.

rama wrote:Also if its not obvious, be sure to install your BT probe where the bean mass is when the drum is tumbling. It should be the clean spot on the back wall from the abrasion.

It pays to start with a well used roaster as the bean mass area is well delineated.