OpenAstroMount EQ5 Style Tripod

After looking at the epic prices of some tripods, I decided to design and make my own!

In short, this is an EQ5 style tripod designed for OpenAstroMount. The mount sits on a 51115 thrust bearing and secured by an M12 bolt housed in the tripod head. The nut tightens onto a smaller thrust bearing with a centering bush. The tripod legs are 1 metre 2040 aluminium extrusions and the levelling legs are 300mm 2020. Temu seemed to be the cheapest place to obtain these.

Included is the original FreeCad design. I also have 3mf files.
You can always open the design in FreeCad and export to whatever format you like. I've named all the parts in the design.

Parts Required:

9 x M4 hot melt inserts, 4 or 5 mm length for securing central tube and leveller thumb screws

6 x M4 20mm Thumb Screws (for the levellers)

9 x M4 50mm Allen Head Screws

3 x M4 30mm Screws

18 x M4 Washers

9 x M4 Nyloc Nuts

9 x 30mm M5 Bolts

18 x M5 Washers

9 x M5 Nyloc Nuts

3 x 1000mm 2040 Aluminium Extrusion

3 x 300mm 2020 Aluminium Extrusion

Between 24-48 M4 T-nuts (depending on how secure the leveller needs to be. I went for the lower number)

Between 24-28 10mm M4 Allen Head Bolts

1 x 51115 Thrust Bearing

2 x M12 Nyloc Nut

1 x 100mm M12 Hexagonal Head Bolt

1 x F8-16M (8x16x5mm) Thrust Bearing

Approx 1kg of PETG filament. I find standard glossy stronger than matt or high speed.

OPTIONAL:

2 x 100mm x 12mm x 3mm Weld repair plate. Circular steel plate which adds rigidity to the mounting. I got mine here - https://www.ebay.co.uk/itm/116576815623
The 51115 bearing will still clear the top of the housing without the plates.

What you will need to print:

1 x Tripod Head
9 x Chainplate
18 x Chainplate Bushing
1 x Drilling Template
3 x Tripod Foot
3 x Tripod Leveller
3 x Tripod LegBracket
1 x Tripod Lower Tube
1 x Tripod Upper Tube
1 x Tripod Upper Bearing Bush

Print Profile:

PETG 0.24mm Layer Height, 100% infill for the head, 85% for everything else.

Tripod Head:
Supports: Yes
Type: Normal
NOTE: You'll notice 2 leg areas have flats on them. This was required to fit it onto a 220x220 build plate.

Tripod Chainplate, Chainplate Bushing, Drill Template, Upper Bearing Bush:
Supports: No

Tripod Upper/Lower Tube:
Supports: Raft Only
Layers: 2

Tripod Leveller, Leg Bracket, Tube Adapter:
Supports: Yes
Type: Tree

Assembly:

You may need to drill out some of the M4 holes to 4.5mm if the bolts dont go in freely.

Hot melt inserts need to go into the top of the upper tube and into the sides of the levellers, the narrow side with the 2 holes in. Don't push them in too far, flush with outer surface is best.

The Upper tube should easily push into the lower tube with reasonable force. Drill out the lower tube holes if it is too tight. Use Epoxy resin in the holes and between the surfaces for a good bond and smear the excess around the outside of the join to make it nice and smooth.

Chainplates join the tube adapter to the leg brackets, 3 for each leg. For the middle, the sequence of parts would be M5 30mm bolt -> washer -> chainplate bushing -> chainplate -> chainplate -> chainplate -> chainplate bushing -> M5 washer -> M5 nyloc nut.
Repeat a simliar sequence for the tube adapter end and leg bracket end.

Use the drill template to drill 3 holes in the top of each 1000mm 2040 extrusion. I marked each hole with a 3mm bit and drilled out with a 5mm bit. Try to drill the holes central in the channels, the template might be a bit off.
I haven't modified the tripod head yet for clearance so you will need to file the narrow sides of the top of the 1000mm extrusions (drilled end) to a 45 degree flat about 4mm wide. This is needed for smooth operation of the legs. I need to make a modification to the head so this doesn't need to be done but haven't got around to it yet.

At the other end, secure the levellers with a minimum 4 x M4x10mm and t-nuts. It helps to also insert the 2020 extrusion at this point as this needs to move freely once the leveller is tightened so good do check and move things around at this point.
The foot attaches to the 2020 section with 2x M4x10mm and t-nuts. The pointy bit points inwards. Everything is angled 25 degrees so these should be vertical when the tripod is fully open.
The 2020 sections are secured using 2 x M4x20mm thumb screws, screwed into the hot melt inserts. This is why the extrusions are 300mm, to provide plenty of friction.

Legs secure to the head using a 50mm M4 bolt with a washer at each end and a M4 nyloc nut. Start with the fixed hole. This one can be done up fairly tight. The other 2 holes use the same hardware but leave them a bit loose for smooth operation and to avoid snapping the legs off the head. These can be tightened when the legs are extended for more rigidity. I might make a better mechanism one day.

The leg brackets secure to the legs 335mm down from the tripod head with the legs extended. Use a 10mm M4 with a t-nut on both holes. Do these up quite tight.

Next, insert the 12mm bolt into the base of the head from the bottom. You'll have to screw it in as the hole is intentionally close tolerance. Use an M12 nut and washer to pull the hex head into the plastic moulding nice and tight. Once captive, the nut and washer can be removed.

The upper/lower tube assembly now needs to be fed through the tube adapter and secured to the tripod head with 3 x 30mm M4 bolts/screws

Now drop one of the optional steel plates over the M12 bolt if you are using them.

The M12 Bolt can now be secured using an M12 washer and M12 nyloc nut.

Next comes the 51115 bearing followed by the second steel plate if you are using them.

You OpenAstroMount will need a 13mm hole drill in the bottom where the EQ5 adapter would normally go. This is the section of 2060x100mm extrusion in the base. I put my hole nearest the balance point.

The mount now goes onto the M12 bolt, followed by the smaller thrust bearing. The small bearing has a smaller hole in one surface. Put this on the bottom. The upper bearing bush should slip over the bolt and go into the bearing keeping it central. Tighten it all down with an M12 nyloc nut.

I've designed this so it can accept the auto PA mount secured in the same way as a standard EQ5 tripod. You will just need to use bigger washers on the M4 bolts.

I tested this out with OpenAstroMount, a home built 6 inch newtonian with raspberry pi and DIY refrigerated pi HQ camera with liquid cooling and a 10000mAh, 21V lipo battery pack (2x 5000mAh 5S packs) acting as the telescope counter weight. In all, there is about 25kg sitting on this thing.

It is reasonably sturdy and should be good on most nights. I wouldn't trust it to take clear images if it is windy.

I'm certainly no CAD expert so this is entirely a case of make cube/cylinder, resize and cut another shape out of it. I don't use sketch or draft yet in FreeCad.

Have fun! Make as many modifications or suggestions as you like.