My CNC Router Build Adventure

[peteeng]

Hello All - I have received an email back from Gates Denver. The GT2 with 5mm pitch has a specific stiffness of 86,000 lbf per inch (Thank you Michael Bruha) . The AT5 has a specific stiffness of 100,500 lbs per inch. Now I have a number. By the way the ATL5 is 133,600 lbf per inch.

Mactec - I have not used the ATL because it is twice the cost per metre and I have to order it special through a company that I prefer not to deal with. I can get C7 ballscrews for less $/m then using an ATL belt system.

My belt drive machines use open belts and they have their own difficulties....My products are cost sensitive and I have to make cost vs performance decisions on every part in the machine to get the machine to the required build cost. Mactec you seem to not understand that wringing technical and commercial information from some companies is a difficult task. You make your own parts to your spec and thats great, I have to live with commercial parts where possible and with customers that don't want to spend a lot of money. This business development phase has been an interesting experience. Precision costs exponentially as you get more precise. I don't disagree with many of the things you say its all relative to the product and its the relative statements that get us into trouble so I prefer to stick to the numbers. Peter

In this little foray I have also come across pulleys that are for AT (and others) belts with less clearance and claim zero backlash, so pulleys could be a good solution if needed. Breco have std, reduced and zero backlash spec... see page 8

https://www.brecoflex.com/wp-content...ley_july08.pdf

[peteeng]

Hi Jayne - The T series and AT series have different flank angles. Use AT vs T and use an AT belt and matching AT pulley. Most pulleys come piloted and you will have to finish the bore to suit. 2 screws is enough and the hole in the pulley does not affect the belt - deburr well or slight counterbore. I recommend loctiting the pulley on once set. Sometimes the small things take the longest time. Peter

edit- PIES in Melbourne are the Breco distributor for OZ. They also have taper locks which are much better then set screws but do cost more.

[mactec54]

Hello All - I have received an email back from Gates Denver. The GT2 with 5mm pitch has a specific stiffness of 86,000 lbf per inch (Thank you Michael Bruha) . The AT5 has a specific stiffness of 100,500 lbs per inch. Now I have a number. By the way the ATL5 is 133,600 lbf per inch.

Mactec - I have not used the ATL because it is twice the cost per metre and I have to order it special through a company that I prefer not to deal with. I can get C7 ballscrews for less $/m then using an ATL belt system.

My belt drive machines use open belts and they have their own difficulties....My products are cost sensitive and I have to make cost vs performance decisions on every part in the machine to get the machine to the required build cost. Mactec you seem to not understand that wringing technical and commercial information from some companies is a difficult task. You make your own parts to your spec and thats great, I have to live with commercial parts where possible and with customers that don't want to spend a lot of money. This business development phase has been an interesting experience. Precision costs exponentially as you get more precise. I don't disagree with many of the things you say its all relative to the product and its the relative statements that get us into trouble so I prefer to stick to the numbers. Peter

In this little foray I have also come across pulleys that are for AT (and others) belts with less clearance and claim zero backlash, so pulleys could be a good solution if needed. Breco have std, reduced and zero backlash spec... see page 8

https://www.brecoflex.com/wp-content...ley_july08.pdf

That was my point ATL series if you can't use it. because of cost, and it is special order as well, why talk about it, you can't bring it into the mix even though it is no better than the standard GT3

The number you have quoted are incorrect, for the GT 3 or any of the GT series, they go up as high as 360,000 and the lowest is 155,000 using polyester

The numbers are worthless if you have no understanding, of what it means to the end result. Tooth clearance is more important, for this application, as any of the Belts will have the strength and stiffness beyond what is needed.

Yes I use Breco some times, they are more expensive, than others, but they do make all there, timing pulleys Etc.

[davida1234]

They also have taper locks which are much better then set screws but do cost more.

That looks like total overkill. SDP/SI has single piece clamp collar pulleys which work very well, do not damage the shaft and cost only a little more than set screw pulleys. I have them on all of my motors.



T Timing Belts and Pulleys

[peteeng]

Mactec - I give up. The number is as quoted by the Gates application engineer for the GT-5MGT belt. Not interested in going further with this topic here. We have hijacked Jaynes thread enough. Peter

David they look good, have not seen them before thanks - Peter

[JayneV]

Hi everyone,

I don’t mind some healthy debate as long as it all remains respectful. I am learning lots here and it’s all relevant discussion, you haven’t hijacked anything. The good thing about using belts is that it is very easy to switch over to a different system, whether it be AT, GT or something not yet invented. It’s just a matter of swapping the pulleys and belt and it’s done. What is available in Australia is usually a limited sample of what is available in America or Europe. Manufacturers may have a presence here with a local website and make their catalogues available but many items are either special order or just plain unavailable to buy. If you dig around enough, it’s possible to find a way to purchase the items you want but that comes at a cost. As an example, we had a $100 voucher to spend in the iFIT online store as reward for completing certain challenges in a fitness program. At the time, iFIT did not ship outside of the US so the voucher was worthless to us. I contacted a friend who lives in Virginia and had the item shipped to her so she could then send it here. The item was a heart rate monitor that fits over your arm, no larger than a watch, yet the shipping costs were $70. With the exchange rate, it would have been cheaper to throw away that $100 voucher and just buy a similar device locally. My point is that costs can escalate very quickly without a proportional increase in value for money.

davida1234, the clamp collar pulley looks good. It might be a good way to go if they are available here and reasonably priced.

Jayne

[JayneV]

I just went through the process of placing an online order (stopping short of actually making payment) for a 450mm GT3 belt from SDP/SI to see what they charge for shipping. The belt costs $25 and shipping is $162. I will obviously never be ordering anything from there, but they have some good info and online calculators I can use, plus they have CAD drawings for the products which could save me some time drawing.

Jayne

[mactec54]

Mactec - I give up. The number is as quoted by the Gates application engineer for the GT-5MGT belt. Not interested in going further with this topic here. We have hijacked Jaynes thread enough. Peter

David they look good, have not seen them before thanks - Peter

I posted the link to there site a few posts back, if you had cared to look.

[mactec54]

I just went through the process of placing an online order (stopping short of actually making payment) for a 450mm GT3 belt from SDP/SI to see what they charge for shipping. The belt costs $25 and shipping is $162. I will obviously never be ordering anything from there, but they have some good info and online calculators I can use, plus they have CAD drawings for the products which could save me some time drawing.

Jayne

That shipping cost is crazy, yes the information on there web site is very good, especially the calculator. it is very accurate for the center distance calculation, as long as you plug in the correct information
.
That shipping cost must of been using DHL or some other shipper like them. you would look at a shipper like this https://www.shipnex.com/internationa...ping/australia

[davida1234]

I just went through the process of placing an online order (stopping short of actually making payment) for a 450mm GT3 belt from SDP/SI to see what they charge for shipping. The belt costs $25 and shipping is $162. I will obviously never be ordering anything from there, but they have some good info and online calculators I can use, plus they have CAD drawings for the products which could save me some time drawing.

Jayne

Once you get to that point, I could order for you whatever you need and send the package to you. I am in California and have no idea if that could save you some money. I could use the carrier mactec54 suggested and see what the cost would be. However, I would take no liability in terms of shipping/delivery or the contents/quality of the order.

[JayneV]

That shipping cost is crazy, yes the information on there web site is very good, especially the calculator. it is very accurate for the center distance calculation, as long as you plug in the correct information
.
That shipping cost must of been using DHL or some other shipper like them. you would look at a shipper like this https://www.shipnex.com/internationa...ping/australia

Yes, it is crazy but is also very common from US suppliers. Over the years, I have tried ordering many different items from the US but could not complete the order either because the vendor does not ship internationally or their shipping costs are outrageous. The shipping costs SDP/SI where with UPS, it was the only option available. USPS is usually the cheapest if the bender offers that option but even that is expensive if a small item the size of a watch cost me $70 to ship, it hitch is actually AUD$93.The exchange rate is a significant factor. USD$1.00 = AUD$1.34 with today’s exchange rate, so anything we buy from the US costs 34% more than the listed price. The cost/benefit of purchasing small quantities from US makes it too expensive to consider. It’s one of the down sides of being so isolated from the rest of the world. There are several companies that offer a parcel forwarding service to cater to countries that vendors don’t ship to but even they tend to be expensive and any shipping warranties offered by the vendor are void when a third party is introduced, which is not really a concern for something like belts and pulleys but is something to keep in mind.

[JayneV]

Once you get to that point, I could order for you whatever you need and send the package to you. I am in California and have no idea if that could save you some money. I could use the carrier mactec54 suggested and see what the cost would be. However, I would take no liability in terms of shipping/delivery or the contents/quality of the order.

Hi David, thank you, that is a very kind offer, but the cost of the items is still too high even without the cost of shipping. The exchange rate is pushing the price higher than I’d like to spend. I’m actually considering going back to a direct drive design to avoid using belts at all, to save some money and the headache of finding the right belt/pulleys for the job at an affordable price.

[peteeng]

Hi Jayne - Try not to make $$$ decisions at the moment. Make good design decisions. Otherwise you will continue in micro spirals through the project consuming huge amounts of time with no real progress to the project. At the end you can see the big picture and then make $$$ decisions... Peter

[JayneV]

Hi Peter, you are right, but I think it’s also important to have some idea of what materials will be used in the design. The machine would look very different if this was purely a theoretical exercise with an unlimited budget. For example I have been careful to use standard stock sizes of aluminium as much as possible. I don’t want to go too far down a path of it means costs will start to escalate out of control. As for belt vs direct driven screws, direct drive is simpler and cheaper but makes the overall footprint slightly larger. I’m reassessing the available space and I think I can accomodate a larger footprint and keep the current working envelope without being too cramped in the garage. Carlos is currently at v9. I think I’ll take a break from v9 for now and move on to v10 to see how direct drives pan out. Thank you for your input, it’s very much appreciated.
Jayne

[peteeng]

Hi - Only V9 around V20 it will be polished so just half done or half to go? Peter

[JayneV]

Hi - Only V9 around V20 it will be polished so just half done or half to go? Peter

Well v9 is the main version number, there were many minor versions within each version. Lol

[peteeng]

Absolutely par for the process!! I think your through the Fuzzy Front End of the project, onto Roughing then Detailing then Polishing... Have fun. Peter

[JayneV]

Hi everyone,

My brain has gone a little mushy thinking about the CNC pretty much 24/7. I was heading towards burnout. Spending so much time in the design phase was never my intention, this project started out with a purchased, proven fit for purpose design, which I wanted to make a few minor adjustments to suit the materials I already had available. It’s so easy to get carried away with tweaking this and adjusting that, before you know it you are designing a whole new machine practically from the ground up. I would really like to place an order for the parts coming from China with Christmas just around the corner but I t’s probably already too late to expect any parts to be delivered before the new year. However, the design is not quite ready to order any parts yet until I sort out how to drive the screws (directly or with belts), so it was time for a little break to give my brain cells a rest and then return to the CNC with a fresh mind.

To help keep me motivated, I have started modelling the first guitar project for Carlos once it is built. Still needs a lot of work like figuring out how to create complex curves where the neck meets the body. I’m still relatively new to Fusion and I don’t yet know how to do that. It might also be easier to rough out the shape with simpler geometry and then carve and sand the final shape by hand, but addressing those details is still a long way away.

I’ve attached some rendered images of the guitar as it is so far if anyone is interested. I got distracted by the shiny materials in the fusion library and made the last two models from shiny metal. One is bronze with a maple fretboard and the other is platinum with carbon fibre fretboard, just because they were shiny.

I’ll get back to Carlos tomorrow.

Have a great day/ night everyone.
Jayne

[JayneV]

Hi everyone,

After taking a break from Carlos for a few days, I started on v10 to move the motors back to the outside of the frame and direct drive the screws. That wasn't working out, I really like where v9 was going with the screws being belt driven and the motors tucked inside the frame, so v10 was set aside and v9 reinstated as my preferred design. I've sent emails to two suppliers this evening, one was to ptparts again to try and clarify the misunderstanding they had with my original email request.

Jayne

[mactec54]

Hi everyone,

After taking a break from Carlos for a few days, I started on v10 to move the motors back to the outside of the frame and direct drive the screws. That wasn't working out, I really like where v9 was going with the screws being belt driven and the motors tucked inside the frame, so v10 was set aside and v9 reinstated as my preferred design. I've sent emails to two suppliers this evening, one was to ptparts again to try and clarify the misunderstanding they had with my original email request.

Jayne

Putting the motors inside the frame is a good idea, I never do it any other way. even for direct drive, doing it the way Peter did having the motors out the front gets old fast, I said in one of his posts to at least put them out the back of the machine, if you have to direct drive like this.

Just so you have more information on Belts Drives, you will see in this snip, that Trapezoidal Tooth Timing belts are at the bottom of the list of Belts to use for CNC machine drives.

PTparts have HTD Timing Belts listed, this was the improved design over the Trapezoidal tooth design, the GT series came after the HTD, if you decide on something to use I will help with the part numbers, if you have a problem with that part, as even in this snip they have some confusing code numbers for some of the Belts series listed