Off-the-shelf Step Blocks and Clamps For Sea-of-Holes Beds

Fixturing in a sea-of-holes bed requires the right tools. A common fixturing (clamping) solution for sea-of-holes beds are step blocks and clamps.

The High Tech Systems Nomad replacement bed uses an 10-32 (Imperial) threading, the C3D Nomad add-on bed uses an M6 (metric) threading. The C3D SO3 sea-of-holes is M6 as well.

Surprisingly, these are compatible with at least one commercial step block clamping system:

It so happens that 10-32 and M5 screws (used for the set) have the same clearance hole size - 0.201". The clearance hole size of an M6 is 0.242". The clamps in this set are slotted at a 0.250" (and a bit larger).

This which means that one can purchase one or two of these sets and use them with an M5 sea-of-holes. If one has a M6 and 10-32 sea-of-holes bed, they may ditch the M5 hardware that comes with a set and use 10-32 or M6 screws plus the appropriate washers.

I verified this by speaking to their supplier’s technical support and by putting calipers to the actual clamps (I purchased some).

Step blocks and clamps are not for everyone or for all situations - they take up room on the bed - but they are hard to beat for simplicity, easy of placement, ease of use, adjustability, and low profile nature (helps avoid collisions with the fixturing).

With a spoiler board underneath ones stock, they can provide additional “Z” over using the C3D vise - which may be useful for some projects.

As with all clamping devices (collets too!) remember to go “monkey tight, not gorilla tight”.



Thanks for posting this, @mbellon!

If anyone is curious to see how these are used - as I was - you can see them in action in this very thorough tutorial video from Tormach:

Skip to about 2:40 if you are as wildly impatient as I am.

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Great find, Mark! LMS seems pretty responsive to customer needs, so I wouldn’t be too surprised if they came out with a version of the clamping set with M6 studs and no t-nuts.

Step block clamps are pretty versatile. On my Tormach I’ve even used step block clamps to hold down workpieces on a wasteboard which is held in the vise.


I found this in New Zealand - it’s heaps cheap - only about $15USD and trade tools normally only sells good stuff. That said I haven’t tried it out yet and you guys in the US would need to pay freight - but then I had to freight my whole machine :slight_smile:

I wounder if you can get threaded rod made of something softer than aluminium with the same rigidity so it doesn’t damage the threads in the C3D Sea of holes bed, if I could find aluminium thread rod it would be no good because it would inevitably seize with the bed. But monkey vs gorilla is sometimes hard to judge with such small threads. I live on an island so we only have two sorts of tools, hammers and bigger hammers :wink:

Nice! Of course this is half of the set I identified. That would make it US$30 (for two sets) which is still a terrific price.

There’s not much information there. Can you contact them and find out the width the slot in the clamps? It has to be 0.242" (6.15 mm) for an M6 to work.

I wounder if you can get threaded rod made of something softer than aluminium with the same rigidity so it doesn’t damage the threads in the C3D Sea of holes bed,

Certainly one can find alternate material rods and Al alloy is one of them. I can just as easily strip threads with them as with steel rods/screws. Working with precision equipment one should learn how to use them safely and effectively. :smiling_imp:

That said, monkey tight, not gorilla tight, is pretty easy to learn. Use hex socket head screws! Turning the screw is then using a hex wrench and the feel is very similar to tightening the collect nut and collet.

The beds are MIC6 - tool quality Al alloy - are designed for threaded applications. That’s reasonably tough.

In a class, we teach how to tighten things… and discover how most things that people tighten are way over tightened!


I just went at lunch and bought two sets for that reason, they are M6 thread rod :slight_smile: Wow, just checked out the specs on MIC6 plate, that’s cool!

Packaging has a bit of an asian feel… but they look okay.

OOOOOO! Definite asian feel.

You’ll discover that with step blocks and clamps you want different heights and clamp lengths for different situations. Expect to grow into a bunch as you get used to them… As @Randy says “Step block clamps are pretty versatile”.


Sold out! Estimated time back in stock is May! Crazy! Gotta start searching.

Sold out! Estimated time back in stock is May! Crazy! Gotta start searching.

ACK! I may have created a stampede! :joy:



3D printing to the rescue :grinning:


I picked up a set after you posted, thanks for the heads up. They are pretty good for the price, especially for the Nomad’s size. Definitely want to make sure you miss these with your endmill though :wink:


Nice Nick.
How is the anchoring bolt fixed to the Nomad bed? Did you find/post these on Thingiverse or somewhere similar?

I’m actually using a shapeoko 3 with threaded inserts in the wasteboard but they would probably work better on the nomad.

They are quite tall and so clearance with the z axis can be challenging. Yep, they are on thingiverse, just search for step blocks

How did your step blocks from Trade Tools work out on the Nomad? Did you use them on the sea-of-holes bed from High Tech Systems?

I bought them to use on the Carbide 3D OEM sea of holes bed but I havn’t tried them. I’m sure they will be just fine though as the thread is the same.

@nick: I missed this a few months ago… What material did you use for the 3d hold down prints? How have they held up?

@enl_public I just used PLA with 3 perimeters and 50% honeycomb in-fill. They are very solid but I made them quite thick. So i’m probably going to make some aluminium ones based off of @ApolloCrowe’s design

Sometimes there is not enough room for those step blocks, I really like these small clamps for the Nomad:
5 Small Clamps wiith step blocks.c2d (1.2 MB)

Ironically I added step blocks to the design.
You can design your own in Carbide Create, or modify this design.

I made a version out of 1/4" aluminum and they work great, I threaded the rear holes M6


@ApolloCrowe You’re right they do take up a fair amount of room, the issue I had was the height when clamping thick oak panels; I have the old long z axis design on my shapeoko and so the z plate would sometimes crash into the top of the clamps!

As soon as I get one of those threaded tables from Edward I’m going to make a set of the ones like yours :slight_smile:

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