Hottop Americas Repair Procedure
Roasting Drum Alignment
January 2022
 DISCLAIMER: These tasks described here as well as the video presentations are not intended to be all-inclusive instructional videos nor offer advice on appliance repair. They merely illustrate the process. The information here as well as the videos take a lot for granted such as, but not limited to, your knowledge, ability, and safety around electrical devices, proper choice and use of hand tools, techniques to ensure personal safety, protection of property, fire safety, and more. By viewing. listening to, or watching these videos, and/or attempting the procedures on this page, or following any repair or maintenance instructions on the Hottop Americas website, you assume all responsibility and release Hottop Americas and all its employees and contractors from any and all liability. If you do not accept these terms and/or your local laws prohibit such a release of liability, you may not watch or use the information contained herein.

NOTE: Before attempting any cleaning or repair procedures, always read the full instructions and the step-by-step procedures before beginning. You can find these instructions in the Hottop Coffee Roaster Repair Procedures on our website. Additionally, our Video Education Center also has a number of helpful repair videos to augment those step-by-step repair pages. Refer to these before attempting any of these tasks and as necessary during the process.

WARNING
There are times when a roaster is partially disassembled when you may wish to run the machine. Usually this is during troubleshooting or after a repair to test your work before final assembly, but may also be done as part of these maintenance tasks. This may include a short test run with the rear cover removed or the front cover removed and other such procedures. The dangers when doing such testing may include, but are not limited to physical harm to you or others, fire danger, burns, electrical shock, and damage to the machine. The source of these dangers could include:
• Exposed electrical connections
• Moving parts such as the rotating roasting drum
• Heat from the heating element.
If you are unsure about the safety of any task discussed below
or any other repair or testing procedure,
please feel free to contact our
Customer Support personnel at support@hottopamericas.com.
We will be glad to assist you.
INTRODUCTION

    This document is seemingly long and detailed, but it was written in a way that should make it easy to implement for most Hottop owners. Take your time! Roasting Drum clearance and alignment is critical to the life of the Drum Motor and each step is important to get the best results and longest life of the drum motor possible.
    When new, the clearance is set at the factory, but there are situations which may require a realignment such as after installing a new motor, installing an upgrade kit, or when metallurgical changes take place over time. Any scraping or rubbing sounds indicate that an alignment issue exists. A roaster making scraping sounds should not be used until the alignment procedures herein are carried out and the scraping has been eliminated. Follow the steps below to diagnose problems and then proceed to properly align the drum in the roast chamber as necessary.
** After completing any drum alignment procedure you must run an "Empty Roast Test." **

    An 'empty roast' is a full roast cycle completed with no beans in the roaster. Stay with the roaster throughout the roast, and if any scraping sounds are heard adjust the gold screw carefully (CAUTION: Hot Surface!). If you have to turn the Gold Screw more than about 1/4 of a turn or if the sound cannot be eliminated in this way, hit the eject button, allow the roaster to cool, and readjust the drum as documented below in this document.
DRUM ALIGNMENT ORIENTATION

NOTE: Bold numbers and letters in green in the text like this: (B) or this (4) refer to the following diagram. Study it, then read on:

  The design of the roaster has the drum solidly located in the motor drive coupling (1). This position is not meant to change. The pin in the drum's axle should always be fully seated in the coupling as seen at (2). Tension to keep the drum in place is supplied by the bearing plate (3). The front end of the drum's axle is supported in the dimple in the bearing plate (C). The gold knob (5) is meant to keep the front cover in place. When the drum's position is properly set and the gold knob properly adjusted, there should be no need to use it an an adjustment to eliminate scraping or rubbing sounds beyond what is described in the following document.

BEARING PLATE: CHECK FOR SCRAPES, GOUGES, OR WEAR

    Remove the front cover, bearing plate, and roasting drum. Examine the following areas:
• (A) The inside surface of the bearing plate for any evidence of scraping or gouging
• (B) The rear wall of the roast chamber for any evidence of scraping or gouging
• (C) The dimple in the bearing plate for signs of wear. If the dimple appears elongated, oddly shaped, or distorted it is an indication that an alignment problem exists. Refer to the photo below for more on this:

If you see any elongation or distortion, in the dimple of the bearing plate
it should be replaced before proceeding with any adjustments to the roaster!
Go to the Hottop Americas Online Storefront to order a replacement bearing plate.

 Note the difference between the worn area indicated by the red arrow and the unworn area indicated by the green arrow. The wear has moved the position of the drum's axle two or three millimeters off center. This would allow the axle to drop down causing the drum to be at an angle in the roast chamber. This would make it impossible to align the drum and could easily cause the Drum Motor to fail. Regardless as to the location or extent of such uneven wear in this area of the Bearing Plate, if found the bearing plate must be replaced before proceeding with the remainder of this alignment procedure.
HEATING ELEMENT ALIGNMENT

The image above shows the proper location for the Heating Element.
When properly aligned, distance A = B = C
They should all be roughly equal. In other words, the heating element should be parallel to the Roasting Chamber's inner wall.

NOTE: In this photo the Bezel has been removed for better view of Heating Element. Do not remove the Bezel.

      Examine the heating element. It should be properly shaped and parallel to the roast chamber's outer wall- close to it, but not touching the wall. Also check for warping of the element itself. If warped it must be replaced. The element should be parallel to the roasting chamber outer wall throughout its length and width. Note that across its width that the element is not flat but is formed in an arc to be parallel to the roast chamber outer wall.
      The position of the Heating Element is important for proper operation of the Hottop Coffee Roaster. If it is too close to the wall of the roasting chamber heat may be lost and can slow the roast through loss of thermal energy. If the heating Element is too close to the drum it can cause "tipping" (scorching) that can cause bad tastes. Although a rare condition, in the extreme, the heating element may rub on the drum which will cause scraping noises and that can damage the Drum Motor.
      Look at the back wall of the Roasting Chamber where the Heating Element mounts to see the proper distance. The heating element should be the same distance from the Chamber Wall throughout its length. A visual inspection is sufficient- it is not necessary to actually measure the distance.
      If it is necessary to adjust the heating element becasue it is too close to the chamber wall, use care when bending it into its proper location. After bending the outer bars of the Element it may be necessary to make a further adjustment to the center loop of the element. This procedure is for minor adjustments only, and is generally only effective for an element that is too close to the outer wall of the roasting chamber.

CAUTION: Use care not to be injured on sharp edges during this procedure.

      It is easy to bend the element away from the wall with the drum removed, but there are times, such as when the element is too far from the chamber wall and there is insufficient room to move the element towards the chamber wall. In those cases, the adjustment procedure described above may not be effective. It will be necessary to first remove the Heating Element from the roaster for further adjustment as described here:

      Use a suitable pair of pliers to grasp the mounting tab at one end of the Heating Element. Position the pliers so that they cover the mounting hole completely so as not to distort the hole when bending the tab, and far enough away from where the element passes through the mounting tab so as not to disturb the area where they are joined.

For a Heating Element that is too close to the Roasting Drum,
bend the mounting tab by moving the pliers in the
direction indicated by the red arrow in this photo

    A small amount of movement of the tab, just a couple of degrees, is all that will usually be necessary. Repeat on the other tab, and attempt to bend it the same amount as the first adjustment. Use care not to damage the electrical connections nor their ceramic insulators.
    After reinstalling the Heating Element, check the alignment again and adjust as necessary.
    If the element is warped, oddly bent, or twisted in such a way that it cannot be aligned in the manner as described above, the Heating Element will need to be replaced. Go to the Hottop Americas Online Storefront where all replacement parts available will be listed to order a replacement heating element.

INSERT THE DRUM

    Check to verify that the pin through the end of the axle that engages the drum motor coupling is in place and not loose. If loose, the drum will likely need to be replaced. Now, fully insert the drum into the machine by hand and be sure that the drive end of the axle fully engages into the drive coupling.
• (1) When you do so, the axle should smoothly slide into the drive coupling. When fully inserted it should stop quite positively.
• (2) That firm stop indicates that the drive pin in the drum's axle has seated completely into the drum motor's drive coupling and has stopped when the pin hits the far end of the slots in the drive coupling.
    Slide the drum out about four or five millimeters and slide it back in as few times. Each time it is pushed in it should should stop solidly and at the same depth each time.

BEARING PLATE

   Proper bearing plate fitting is important for the life of the drum motor. When replacing the Bearing Plate in this section, make sure the drum axle is properly located in the bearing plate's dimple (C) !


• 1 - Insert the screws loosely to help hold the bearing plate in its place. Note how loose they are in the photo.
• 2 - Lightly hold the bearing plate aligned, ready to engage the alignment pins but do not push it into place. Just hold it against the drum with enough pressure to be sure the drum's axle is fully seated in the drive coupling, but do so without flexing the bearing plate.
• 3 - While holding the plate in this position and keeping it parallel to the face of the bezel, there should be no less than approximately 2 mm but less than about 5mm (about 1/8 to 1/4 of an inch) of clearance between the bearing plate and the bezel. If the clearance is excessive or insufficient the bearing plate needs to be adjusted.
  Another way to test the distance is to only turn the plate's retaining screws in about one full turn after the threads engage. To do that, align the screw in the hole and while hodling it with the screwdriver, turn it counter-clockwise until you feel it sort of "click" into place. Then tighten one full turn from that point. This is an old mechanic's trick to keep threaded parts from cross-threading.

  We are trying to establish the amount of pressure that the bearing plate will exert upon the axle. It needs to be enough to hold the axle in place but not so much as to exert excessive force on the motor's drive or cause accelerated wear to the bearing plate itself. After assessing whether the plate's tongue (the tongue is the "arm" of the bearing plate that holds the drum's axle) needs to be adjusted to achieve that 3mm to 5mm of clearance, and which direction the bearing plate's tongue needs to be bent, the easiest way to deal with that is to remove the drum then reinstall the bearing plate on the roaster and seat the screws (DO NOT OVERTIGHTEN THEM!). Note adjustments to a worn bearing plate will likely be difficult or impossible to accurately set using this method.
 
  With the drum out and the bearing plate screws tighterned, begin by placing a straight edge across the flat surface of the face of the bearing plate to judge the tongue's current position.
  - If the bearing plate in the previous step was LESS than 2mm away from the bezel, bend the tongue INWARDS.
  - If the bearing plate was MORE than 5mm away from the bezel (or if you had to use more force with the scredriver then you would with your fingers alone, bend the tongue OUTWARDS.
  Use the straight edge once again to verify that the adjustment was sufficient.
  Replace the drum, bearing plate, and insert the screws loosely as in the first part of this section. Once again, measure the distance of the plate from the bexel.
  Once the adjustment is correct, hold the bearing plate flush against bezel with one hand, making sure the alignment pins are in the proper holes in the bearing plate and tighten the screws with the other.
  Tighten the four screws now but do not overdo the torque. The bearing plate is not under much actual stress and can easily stay in place with no more than having the screws seated all the way and then very gently tightened just a little more.
    With the bearing plate screws tightened, carefully reach a finger into the roaster right behind the bearing plate and apply upwards pressure to the axle. If the axle moves upwards more than a slight amount there is a problem. The bearing plate is not holding the end of the axle correctly. While holding the axle up attempt to push the tongue of the bearing plate towards the axle. If it moves the plate needs to be removed and the tongue bent inwards just a little. If the problem cannot be resolved, it may be necessary to replace the bearing plate as it is likely too worn to hold the drum.

STOP! Any of the above situations
indicate an alignment problem which must be addressed
before continuing with the drum alignment procedure below.

DRUM CLEARANCE VERIFICATION

   With the roaster assembled, with the exception of leaving the front cover off, the correct distance between the drum and the rear wall of the roast chamber (4) is around 1 millimeter and no more than about 1.5mm from the rear wall of the roast chamber when that drum is fully inserted into the drive coupling (this is approximately 0.05"). It must be less than than 2 millimeters. Be aware that this measurement is critical. To describe the distance between the back end of the roasting drum and the rear wall of the roast chamber less specifically, it should be as reasonably close as possible to, but not touching the rear wall. Following are instructions on how to make a simple tool to check the alignment of the drum in the roast chamber.
    The distance is designed to keep beans from falling into the chaff tray and still allow for thermal expansion of the drum during the roast.
HOMEMADE DRUM-SPACING GAUGE

MATERIALS
  You will need two or three silver paper clips as follows (avoid plastic-covered or painted clips) :
- One standard size 1.25" long. .035" (.89mm) diameter
- One large 2" long .04" (1mm) diameter.
      If you find one that is a little thicker, that would be fine as well to have. Whatever clips you choose, the thick one should should be approximately 1mm to 1.5mm (0.04" to 0.06"), but no more than that! More info on sizes follows:
paper clips

There are a lot of different paper clips available and their sizes vary. Click on the small image here to see a larger image with examples of different clips as well as the dimensions (diameters and lengths). This may make selection of the correct paper clips somewhat easier for you. The very best solution is to have three tools when you finish: One tool that is of the 'correct' diameter and one that is too large and one that is too small.
 Avoid plastic-covered or painted clips.

For Those More 'Technically Advanced':
This tool does not have to be made from a paper clip. If you have an accurate caliper and can find any sort of stiff wire, or electric wire with a solid conductor of similar sizes as listed below, feel free to try it. The sizes below are for uncoated, uninsulated wire only:

Here are the precise sizes rounded off the the nearest .01":
  • 0.08" 12ga. (2.0mm) wire should not fit- it is too big. Gap must be less than 2mm.
  • 0.06" 15 ga. (1.5mm) wire should be a nice fit and not be loose.
  • 0.04" 18 ga. (1.0mm) wire should be a somewhat loose fit.
Another comparison is: An American penny is 1.5mm, an American nickle is 2.0mm.

   Start by straightening one of the paper clips (or wires if you are using that) the best you can with a pair of needle nose pliers. About 1.5" of one end should be as straight as possible. "Close enough" for the remaining length will be sufficient. Using pliers (as seen here), hold the side of the jaws about 1/2" to 3/4" long at the "straightest" end and..
...create a bend which forms an angle as close to 90 degrees as possible 1/2" to 3/4" long.
Here you see the first bend completed.

Create a second bend which forms a 90 degree angle of approximately 1/2" to 3/4" above the first bend.
Make a second bend at 90 degrees in the same direction.

   
The second bend creates a "J" shaped hook at one end of the wire
   

Create a sort of handle on the tool. There should be a length of straight (unbent) wire which is a minimum of about 2.5" to 3" in length from the last bend. This distance is not critical as it just has to be long enough to end above the top of the roaster when the tool is in use and give you an easy place to grip the tool.

Repeat this process to create the second (and third, if you so choose) tool using the other paper clip.

    The tools are now ready for use!
Refer to the following illustration and description
on how to use the paper clip tools you just made

• Leave the front cover off while making these measurements.
• The bearing plate screws must be tight and not left loose.
• Remove the bean loading chute cover.
• Slide the "thicker" paper clip tool you made down into the chute and insert it into the roast chamber.
• Slide the end of the tool upwards so that it is inserted between the rear end of the drum and the rear wall of the roast chamber.
    It may take a bit of practice to get it into place. Looking into the roast chamber with a flashlight the first few times will help you find and "feel" the correct location.
    Gently move the tool about and slide it up and down a few millimeters to get the feel of how to judge the gap. Let the tool settle into where it wants to be by using a soft hold on it with just a light "pinch" of your fingers. Now do the same with the "thinner" tool you made. Manually rotate the drum 1/4 turn and repeat the same check (Use care when rotating the drum!). Repeat until one full revolution of the drum has been checked in that manner.
  Ideally, the 1.5mm paper clip tool should show a bit of resistance when sliding it around in the gap. The 1.0mm tool should fit loosely. If both of those conditions exist then the drum is in good alignment.
If that is not the case:
• If the thick tool fits too easily with excessive space left it means the drum is too far from the rear wall and you need to adjust the drum clearance.
• If the thin tool cannot be inserted it means that the drum is too close to the rear wall and you need to adjust the drum clearance.

NOTE: Remember that we are dealing with fractions of an inch:
    1mm = 0.04"
    2mm = 0.08"

DRUM CLEARANCE ADJUSTMENT

    In the previous section you 'measured' to quantify whether the drum was in correct horizontal alignment in the roast chamber. If you found that the drum was properly located, skip this section and go directly to the "Gold Knob section below. If your paper clip measurements showed that the drum was either too close or too far from the roast chamber's rear wall, the adjustment can be made by following the instructions below:

** READ AND UNDERSTAND THIS ENTIRE SECTION **
** BEFORE ATTEMPTING THIS ADJUSTMENT **

It is important to understand that the minimum distance between the Drum and the Roast Chamber's Rear Wall is a constant in actual use, but which can be adjusted by following these instructions. The distance is set by the drive pin's position in the motor coupling. Although you are tapping on the axle in the following adjustment, what you are actually achievinmg is moving the drum's position in relation to the axle.

align drum with hammer
The user found that the drum was
TOO FAR from the rear wall.
The user is now moving the drum
CLOSER TO THE REAR WALL

If The Drum Is TOO FAR FROM THE REAR WALL Of The Roast Chamber
Use a non-marring hammer and gently tap the end of drum's axle to that is inserted into the drum motor's drive coupling. Tapping the axle in the direction shown in the photo MOVES THE DRUM CLOSER TO THE REAR WALL of the roast chamber.

If The Drum Is TOO CLOSE TO THE REAR WALL Of The Roast Chamber
Use a non-marring hammer and gently tap the end of drum's axle on the end that rests in the bearing plate. Tapping in that direction (not shown here) will MOVE THE DRUM AWAY FROM THE REAR WALLf the roast chamber.

IMPORTANT:
  Even though the drum and axle are made of heavy metal, DO NOT think it takes a hard hit with a hammer to move the axle. You must use one or two GENTLE taps, and it is best to use a light hammer if you have one. In most cases you are likely only trying to move the shaft one or two millimeters (which is less than 1/10th of an inch)!
  After tapping once or twice, replace the drum, reassemble the machine, and check the clearance again using your paper clip tools. You will likely need to repeat this adjustment a few times to get the proper alignment.
  If an adjustment was necessary and the drum is now properly located in the roast chamber, you should recheck the spacing after the next two or three roasts. This is because the heating and cooling cycles the roaster will experience may allow the metal to "relax" and cause the drum to move towards its previous, incorrect alignment.

HELPFUL TIPS
    Hold the drum in the air in one hand. Doing this over a bed, sofa, stuffed chair, or other soft surface is recommended just in case the drum slips out of your hand. Do not place the drum on a fixed surface! If you have difficulty holding onto the drum, have another person hold the drum while you tap. Use a non-marring hammer and gently tap straight downward on the end of the drum's axle.

THE GOLD KNOB

  The Gold Knob should not have to be tightened more than a tiny amount past just seated. It only has to be tight enough to hold the front cover in place on the machine and to avoid beans or chaff from falling out of the roasting chamber. That is the Gold Knob's main purpose. But during a roast, heat can expand metal parts and so it is possible that a SLIGHT adjustment may have to be made. If the noise is from the front of the machine then try a tiny dab of food safe, heat resistant lubricant on the end of the axle where it is held in the dimple of the bearing plate.

If the scraping sound is from the frint of the roaster you may need to tighten the Gold Knob a tiny amount; no more then about 1/8 of a turnIf it needs more than that, you have some other problem that should be addressed (worn drum axle, warped drum, worn bearing plate, etc.). If the scraping sound is coming from the rear of the drum, then the alignment procedure in the previous section needs to be revisited.

TESTING
** After completing any drum alignment procedure you must run an "Empty Roast Test." **

  An "empty roast" is a full roast cycle but do not add beans. Stay with the roaster throughout the roast, and if any scraping sounds are heard, immediately hit the eject button. Allow the roaster to cool and readjust the drum as necessary.  

If you are unable to adjust the drum, if scraping sounds are still heard, please contact support at support@hottopamericas.com.
If we cannot help you solve the problem the machine may need to be returned to us for examination and repair.