Designing a rack

[Illgresi]

Hello all,

I'm sure we're all thinking about the idea of working out at home, given the current pandemic. I've just watched Rippetoe's video from last year on Youtube about building a home gym. Clearly one of the most fundamental pieces of equipment is a rack. They can be damn expensive.

That got me to thinking about designing one myself, being a mechanical engineer that works for a company who fabricate steel, I feel I could probably design and manufacture one for a fraction of the cost.

The issue is, I'm no more than what is described as an advanced novice lifter. I know what features are useful to me, but I don't necessarily know what is useful to an intermediate, or advanced lifter. Personally, I want:

• Lots of small gradations for varying height (the closer the better)
• Enough height to press inside
• A fixed bar at the top for chin ups

Are there any other features of a rack that you like/desire?

Let me know, and I'll keep you all updated on the design if anyone is interested!

[Mark Rippetoe]

This has already been designed. It's in the blue book.

[Lost and Found]

Plate storage on board for stability if you are not bolting to the floor/platform. It's also nice to keep the lifing area neater.

I know a metalwork/welder who thought the same thing about building one cheaper. He got it finished and it was nice but he said he would never do it again.

[bikesandcars]

Hello all,

...being a mechanical engineer that works for a company who fabricate steel, I feel I could probably design and manufacture one for a fraction of the cost....

One of the things that makes engineers effective is their willingness to take on any project, their mindset that they can do it cheaper/better, and the way they totally discount their time or how long it will take.

I've learned over time that I generally can't beat the market if the market is mature. Quality racks are everywhere and cheap. IF a rack is $600 and half is material, that gives you $300 to play with. If your time is worth $50/hr that gives you 6 hours to make the rack... good luck!

If you want to build one for fun and for skill do it, or if there are features you can't buy that you need then that might be worth it. I've learned my lesson, don't do it because you can make a better one cheaper.

I'm a mechanical engineer.

[Illgresi]

This has already been designed. It's in the blue book.

Ahh, right you are, albeit in US section sizes. Is there a particular reason why you stated you prefer channel over box section?

Plate storage on board for stability if you are not bolting to the floor/platform. It's also nice to keep the lifing area neater.

I know a metalwork/welder who thought the same thing about building one cheaper. He got it finished and it was nice but he said he would never do it again.

I would likely fix with mechanical anchors, however a litte plate storage could still be a good idea.

[Steve R]

You should consider using 3" square steel tube with 1" holes because of the many accessories that are available to fit these dimensions. And you can always use 1" bolts of the proper length as barbell hooks if you don't want to buy J hooks.

Welding the side panels and connecting them with your pullup device will give you a good compromise between stability and portability.

Much of the manufacturing cost is in machining all the holes which give unlimited attachment points on racks such as the Rogue Monster. You're making a rack for your own use so you only need to machine the holes that you will use.

Pin pipe safeties such as the ones sold by Rogue should be easy for you to duplicate if needed.

Good luck!

[Mark Rippetoe]

And the hole punching expense is doubled with square tubing.

[jddichello]

Ahh, right you are, albeit in US section sizes. Is there a particular reason why you stated you prefer channel over box section?



I would likely fix with mechanical anchors, however a litte plate storage could still be a good idea.

I can't remember what video it was in, but having square tubing only allows for straight lines since its passing through two walls. C channel has 1 wall to pass through allowing you to set the pins at an angle to replicate the use of J-hooks. Honestly if you had any welding skills, and have access to a iron worker press or a Hougan drill with annular cutters, this rack is extremely cheap to reproduce. As you have seen this rack can hold more than most any of us will ever be able to lift as well. On the note of drilling holes, you can get by with a few bi-metal hole saws, at a slower speed and using cutting fluid to drill holes with a drill press. Just make sure the channel is very secure, measure, and measure again then center punch it. I love doing this type of stuff as my job and wouldn't explaining more if you need some help, but I wouldn't try to learn welding on this type of project if you haven't welded, or have very little welding experience.

[Illgresi]

Thanks all for the replies, plenty to think about.

One of the things that makes engineers effective is their willingness to take on any project, their mindset that they can do it cheaper/better, and the way they totally discount their time or how long it will take.

I've learned over time that I generally can't beat the market if the market is mature. Quality racks are everywhere and cheap. IF a rack is $600 and half is material, that gives you $300 to play with. If your time is worth $50/hr that gives you 6 hours to make the rack... good luck!

If you want to build one for fun and for skill do it, or if there are features you can't buy that you need then that might be worth it. I've learned my lesson, don't do it because you can make a better one cheaper.

I'm a mechanical engineer.

I'd like to think I can do it cheaper, and as well. Whether I can design something better is a different question. Firstly, does it really need to be better? I think if I'm taking the time to design it, I might as well have a go at improving the design, or adding features.

The main issue in costing the project is that I won't be charging myself labour! The cost of the steel (and consumables), are the only costs I will have. Granted if this was a commercial venture, labour would be a major factor, and would also influence the design. In fact, as an engineer, I will design it with ease of fabrication in mind. It's what we do. However, labour isn't a consideration for me designing and manufacturing myself.

And the hole punching expense is doubled with square tubing.

As above, if the cost of punching (or more likely cutting using a magdrill, or even more likely bought cut and drilled) is a consideration, I can happily accept that. In this instance, I would be borrowing equipment from work, and perhaps an hour of expertise from my manager (paid for in beer or gin no doubt). However, I assume from your response there is no training oriented or actual usage difference?

You should consider using 3" square steel tube with 1" holes because of the many accessories that are available to fit these dimensions. And you can always use 1" bolts of the proper length as barbell hooks if you don't want to buy J hooks.

Welding the side panels and connecting them with your pullup device will give you a good compromise between stability and portability.

Much of the manufacturing cost is in machining all the holes which give unlimited attachment points on racks such as the Rogue Monster. You're making a rack for your own use so you only need to machine the holes that you will use.

Pin pipe safeties such as the ones sold by Rogue should be easy for you to duplicate if needed.

Good luck!

I'm in Scotland, so we use Eurocode sizes here; the closest anologue to a 3" box section would be SHS 80. I would have to do the calculations, but I would imagine a fairly light section, let's assume 5mm wall thickness. We're talking £12/m, although I'll allow another 25% for buying cut and drilled to length...so £15/m. I'm a shade under 6', and with arms extended I'm around 2.2m. So a 2.3m height is good for me to press under. Assuming I use SHS alround (not including the front top, which will be 25mm round bar), and working on our 3D software, I will need at most 14m of SHS 80x5, so £168. Then I need fittings (i.e. endplates) to bolt it all together. We usually estimate plasma cut fittings at ARP*£2150/t, and I would imagine the fittings will be around 15% of the total weight (155kg). So I will allow £50 for plates. If mechanical anchors are required I generally allow £80 per t, so in this case...£12 for fasteners.

So in terms of raw ingredients, I would expect the project to cost in the region of £230.

I love the notion that I only need to place holes where I need them! In fact...the vast majority of us are within a range of 5'7" to 6'3", and so optimal bar position is only going to change by at most 200mm. So I only need holes around that area. However I also need holes to protect me at the bottom of the squat. I also need holes to protect me when I'm benching hard. I could also need that when pressing (albeit you're never attempting a press you can't hold on your shoulders). When you take into account these different potential requirements, and different 'heights', it actually makes sense to have multiple levels.

I can't remember what video it was in, but having square tubing only allows for straight lines since its passing through two walls. C channel has 1 wall to pass through allowing you to set the pins at an angle to replicate the use of J-hooks. Honestly if you had any welding skills, and have access to a iron worker press or a Hougan drill with annular cutters, this rack is extremely cheap to reproduce. As you have seen this rack can hold more than most any of us will ever be able to lift as well. On the note of drilling holes, you can get by with a few bi-metal hole saws, at a slower speed and using cutting fluid to drill holes with a drill press. Just make sure the channel is very secure, measure, and measure again then center punch it. I love doing this type of stuff as my job and wouldn't explaining more if you need some help, but I wouldn't try to learn welding on this type of project if you haven't welded, or have very little welding experience.

As I mentioned above, chances are I would buy it cut to length, and pre-drilled. I would also buy the end plates plasma cut.

The actual fabrication could be done by myself, for a great deal less cost, but would be considered a labour cost. That labour cost (i.e. me doing it) could be seen as a financial cost. However for me, it's a social cost, as it would detract from the time I get to spend with my 9mth old boy.