Calculating the cable length for a highlift conversion and double checking my math

[general ike]

Hey all, absolutely great info on this forum. I have been doing some research on a highlift conversion to give me some room for my four post car lift. I have it mostly figure out, thanks to you all but I have run into a road block trying to figure out my cable length

I plan on using a cable drum D400-54 highlift and I currently have the following:

123" floor to ceiling height
96" high door
107" floor current shaft center
19.5" track to ceiling

I am hoping to bring the shaft to 3" from the ceiling (120" from the floor} and the track 6.5" from the ceiling (117" from the floor) in that I need every bit of clearance I can get. I think I can still get a side mounted motor in the future. My highlift would be 21"if my numbers are correct.

So first off are my calculations correct? I know its tight but will it work?????

I am also trying to determine cable length. I know its not simple and that you want the cable to reach the flat part of the asymmetrical drum just as it goes horizontal on the track so you might need to wind some of the cable before the drum starts moving. I found the following formula:

" Floor to shaft center +63" minus amount of hi-lift" . so my calculations make he cable length 162" long That seems like it would create a lot of excess cable wrapped around the drum? Could this be possibly be correct? It seems like it would take up all the tapered section. It does not seem to make sense.

I could use some help here before I start purchasing parts. So I would greatly appreciate any and all help. Thanks Ike

 

[pattenp]

If you're thinking about a jackshaft opener in the future you need to keep the center of the cable drum shaft at least 4 inches from the ceiling. 3 inches is really cutting it close. My shaft is right at 4 inches on center from the ceiling and top of the opener is about 1 inch below the ceiling.

 

[jstroede]

Hey all, absolutely great info on this forum. I have been doing some research on a highlift conversion to give me some room for my four post car lift. I have it mostly figure out, thanks to you all but I have run into a road block trying to figure out my cable length

I plan on using a cable drum D400-54 highlift and I currently have the following:

123" floor to ceiling height
96" high door
107" floor current shaft center
19.5" track to ceiling

I am hoping to bring the shaft to 3" from the ceiling (120" from the floor} and the track 6.5" from the ceiling (117" from the floor) in that I need every bit of clearance I can get. I think I can still get a side mounted motor in the future. My highlift would be 21"if my numbers are correct.

So first off are my calculations correct? I know its tight but will it work?????

I am also trying to determine cable length. I know its not simple and that you want the cable to reach the flat part of the asymmetrical drum just as it goes horizontal on the track so you might need to wind some of the cable before the drum starts moving. I found the following formula:

" Floor to shaft center +63" minus amount of hi-lift" . so my calculations make he cable length 162" long That seems like it would create a lot of excess cable wrapped around the drum? Could this be possibly be correct? It seems like it would take up all the tapered section. It does not seem to make sense.

I could use some help here before I start purchasing parts. So I would greatly appreciate any and all help. Thanks Ike

When you say to get the track 6.5" from the ceiling, what part of the track are you talking about? You have provided some good numbers. I don't have much time now but I will sit down and run through your numbers today if you can tell me where this 6.5" number comes from, as well as the 19.5" number. Bottom of the track? Top of track? How are you going to build the high lift portion?

For the relatively small amount of high lift, yes you are going to have cable wrapped on most of the tapered part of the drum. That is correct. Your CL shaft is probably going to need to come down a bit. That is a 6" max od drum, so you need a little space between the ceiling and drum. Off an inch or so will have virtually no affect on how the door springs.

John

 

[firebirdparts]

I've never seen that formula, but it does make some sense to have one . You only need 21 inches to roll off the cone area of the drum. They claim that the drums were designed for a max of 54" high lift, so you can see that in that max case, they thought you'd have just 9 inches on the drum in the max install.

That sounds fine to me, honest. So I redid my math here. It has 4 turns on that cone. The big diameter is 5.5 inches, vs. the small at 4.5 inches, so in 4 full turns you'd get about 63 inches on there.

It all does make sense if you understand how it works.

 

[pattenp]

Based on my setup and adjusting by your numbes I get 134" cable. Shaft height 119" + 1 drum wrap 15" = 134". I assumed keeping shaft 4" O/C from ceiling. I have 96" door with those same drums. With door closed there is 1 wrap of the cable on the drum.

 

[pattenp]

See this site for good info. https://ddmgaragedoors.com/

 

[pattenp]

I found the site where you got that formula. If I use it on my door I'd have my drums loaded with about 3 to 4 wraps of cable when closed. Seems to be alot of excess cable and defeats the purpose of the stepped wraps at start of lifting.

 

[general ike]

Thanks all I greatly appreciate the help. Some answers and more questions:

John thanks for the response!!! I have been somewhat inconsistent with my measurements when it comes to he track sadly. The home its in is a summer house that I am only there every other weekend so I cant simply go out and remeasure, but I have taken alot of pics. To answer your question the 19.5 in measurement is to the ceiling from the TOP of the track. My 6.5" new track position comes from me moving the center rod/shaft from its current position up by 13in and then subtracting that from the tracks current position. So 19.5in minus 13in gave me my new track position of 6.5in. Again the top of the track measurement.

(How are you going to build the high lift portion?) I am not sure if this is what you are asking. The highlift section will come from a old track and will angle off at 7 degrees to meet the radius portion of the track .

I thought the drum was 5.5in in diameter so I gave it 3in for clearance. Too close? Since the door will not come back as far I may not need to be so tight to the ceiling.

Pattenp I looked up the specs and it required 3in from the ceiling. Again trying to squeeze out every inch.



Firebird thank you for the response. I looked and several sites quote the same formula. I freely admit that I am not clear on the math here!!!!

This is what I don't understand , if the top of the drum is approx 122" from the floor and the cable is 162" doesn't that mean that 40" of cable will already be wrapped around the drum with the door in the down position basically negating the cone area of the drum? It seems like a lot of he cone section would be gone.

I was thinking off trying to reuse my springs since I am not raising the door that high and winding them tighter. Realistic?

Thanks again all.
Greatly appreicted!!! Ike

 

[jstroede]

I found the site where you got that formula. If I use it on my door I'd have my drums loaded with about 3 to 4 wraps of cable when closed. Seems to be alot of excess cable and defeats the purpose of the stepped wraps at start of lifting.

Yes, it is exactly how the drum is supposed to work. It is not excess cable. Only the portion of the door in the high lift area should use the tapered portion of the drum. Once the top section begins to kick over to horizontal, that's when it should transition to the flat of the drum.

John

 

[jstroede]

Thanks all I greatly appreciate the help. Some answers and more questions:

John thanks for the response!!! I have been somewhat inconsistent with my measurements when it comes to he track sadly. The home its in is a summer house that I am only there every other weekend so I cant simply go out and remeasure, but I have taken alot of pics. To answer your question the 19.5 in measurement is to the ceiling from the TOP of the track. My 6.5" new track position comes from me moving the center rod/shaft from its current position up by 13in and then subtracting that from the tracks current position. So 19.5in minus 13in gave me my new track position of 6.5in. Again the top of the track measurement.

(How are you going to build the high lift portion?) I am not sure if this is what you are asking. The highlift section will come from a old track and will angle off at 7 degrees to meet the radius portion of the track .

I thought the drum was 5.5in in diameter so I gave it 3in for clearance. Too close? Since the door will not come back as far I may not need to be so tight to the ceiling.

Pattenp I looked up the specs and it required 3in from the ceiling. Again trying to squeeze out every inch.



Firebird thank you for the response. I looked and several sites quote the same formula. I freely admit that I am not clear on the math here!!!!

This is what I don't understand , if the top of the drum is approx 122" from the floor and the cable is 162" doesn't that mean that 40" of cable will already be wrapped around the drum with the door in the down position basically negating the cone area of the drum? It seems like a lot of he cone section would be gone.

I was thinking off trying to reuse my springs since I am not raising the door that high and winding them tighter. Realistic?

Thanks again all.
Greatly appreicted!!! Ike

Generally in the high lift calculations, measurements are to the bottom of the horizontal track. For instance, a normal set of standard lift 15" radius track actually has about 7" of high lift built into it. If I were sending a door out shop built, normally I would say bottom of track 12" from the ceiling, but building it on site you can squeeze out a little more. With some fab work, you can work around about whatever CL of shaft you need. Usually to make the high lift "insert" you can cut the material from the back of the horizontal track. You will have to cut material from the radius as well as the vertical track to make your transitions clean. The insert must break back from the wall usually to clear the door by the cable drum as well. If I can get a chance, I will try and lay it out for you. I have been swamped lately though.

Your old springs will not work. Do not even try it. High lift will require longer springs and more turns to hold the doors up. If you give me the old spring dimensions, I can probably use them to back calculate a door weight, unless you know what it is.

You are on the right track I think, just need to sort out a few details.

Also how thick is the door you have?

John

 

[jstroede]

Thanks all I greatly appreciate the help. Some answers and more questions:

John thanks for the response!!! I have been somewhat inconsistent with my measurements when it comes to he track sadly. The home its in is a summer house that I am only there every other weekend so I cant simply go out and remeasure, but I have taken alot of pics. To answer your question the 19.5 in measurement is to the ceiling from the TOP of the track. My 6.5" new track position comes from me moving the center rod/shaft from its current position up by 13in and then subtracting that from the tracks current position. So 19.5in minus 13in gave me my new track position of 6.5in. Again the top of the track measurement.

(How are you going to build the high lift portion?) I am not sure if this is what you are asking. The highlift section will come from a old track and will angle off at 7 degrees to meet the radius portion of the track .

I thought the drum was 5.5in in diameter so I gave it 3in for clearance. Too close? Since the door will not come back as far I may not need to be so tight to the ceiling.

Pattenp I looked up the specs and it required 3in from the ceiling. Again trying to squeeze out every inch.



Firebird thank you for the response. I looked and several sites quote the same formula. I freely admit that I am not clear on the math here!!!!

This is what I don't understand , if the top of the drum is approx 122" from the floor and the cable is 162" doesn't that mean that 40" of cable will already be wrapped around the drum with the door in the down position basically negating the cone area of the drum? It seems like a lot of he cone section would be gone.

I was thinking off trying to reuse my springs since I am not raising the door that high and winding them tighter. Realistic?

Thanks again all.
Greatly appreicted!!! Ike

I forgot to address your question about the cable length. That drum is good for anywhere up to 54" of high lift. You don't have 54" of high lift, so that's why you have all of the cable wrap on the tapered portion of the drum. If you had 54" of high lift, you would have like 1/2-3/4 wrap of cable when the door is down.

John

 

[pattenp]

Yes, it is exactly how the drum is supposed to work. It is not excess cable. Only the portion of the door in the high lift area should use the tapered portion of the drum. Once the top section begins to kick over to horizontal, that's when it should transition to the flat of the drum.

John

What I was trying to get at was if the cable is so long that it uses up the tapered part of the drum before the door starts to open, the cable is into the flat part of the drum before the door is even close to going horizontal. That formula seems to eat up too much of the tapered part of the drum. I'll admit I'm no garage door highlift installation expert.

 

[jstroede]

What I was trying to get at was if the cable is so long that it uses up the tapered part of the drum before the door starts to open, the cable is into the flat part of the drum before the door is even close to going horizontal. That formula seems to eat up too much of the tapered part of the drum. I'll admit I'm no garage door highlift installation expert.

Well the OP only has 17" of high lift, so basically he needs to wrap that first half wrap plus 37" of cable.

I put together this drawing over lunch. This should get very close. A few details on bracing are omitted, but it shows the dimensions.

I do not know the skills of the OP, but with no more than this is, and some handling, it might be able to work with the drums and the springs that are there (obviously would require longer cables). I don't know how the door is sprung now, but with the jack shaft opener that already wants the door to be a little heavy, it could work. I hesitate to suggest it though because I don't know the skill of the OP, but it could be possible. We spring doors on 32" radius, which is 24" of high lift, with standard lift drums all the time. This is similar to that.

John

 

[general ike]

Thanks all!!! John thank you greatly for taking the time to draw this out and calculate everything. Excellent I am a very handy person. Did most of the rehab of my house by myself so this should not be too complicated. I hope!!!!
My confusion and perhaps Pattenp as well is that all the angled portion of the drum is getting unused. But if I understand you well enough because of the limited high lift that I need I may not need the high lift drums at all and may be able to use the conventional drums I now have?
That would simplify everything for sure.
Would you let me know if understand you correctly when you get a chance. No rush. !!
Regarding the springs I believe the door weighs 190 lbs. (double checked my notes and it is 189lbs) but I need to verify that.
My current drums pick. Thanks again everyone. Ike

 

[jstroede]

Thanks all!!! John thank you greatly for taking the time to draw this out and calculate everything. Excellent I am a very handy person. Did most of the rehab of my house by myself so this should not be too complicated. I hope!!!!
My confusion and perhaps Pattenp as well is that all the angled portion of the drum is getting unused. But if I understand you well enough because of the limited high lift that I need I may not need the high lift drums at all and may be able to use the conventional drums I now have?
That would simplify everything for sure.
Would you let me know if understand you correctly when you get a chance. No rush. !!
Regarding the springs I believe the door weighs 190 lbs. but I need to verify that. Thanks again everyone. Ike

A 400-54 drum is good for doors with up to 54" of high lift. That means it works with doors with 24", 30", 48", etc as well. The amount of high lift determines how much of the drum gets used. You can actually use it just like a standard lift drum as well by basically using none of the taper. You are not far from that as you only have 17" of high lift, so you would only use like 1.5 wraps of the tapered section.

Guessing at weight isn't a good idea. If you have the size of the existing springs, I can back calculate it as well.

It isn't complicated, but takes some messing to get it to work. Those guys have a few more tools at their disposal, like doing a set of cables on site if needed. Depending on what type of glass you have in the top section of that door, it could be a little trickier than normal too.

John

 

[general ike]

John the weight of the door is from clopay. I had verified with them. I won’t be able to get the dimensions till the 18th so it might need to wait till then. When you say dimensions do you mean length and width?
The glass is double pane thickness but I think you mean I might need to add a strut to support that section of the door. Correct?

So do I understand you correctly that a standard lift drum may work instead of a highlight type?
Does my existing standard lift drums have enough room to wind the 120+ in of cable I would need? I have not paid attention to it in a up position to see how much more extra room it had.


Thanks again Ike

 

[jstroede]

John the weight of the door is from clopay. I had verified with them. I won’t be able to get the dimensions till the 18th so it might need to wait till then. When you say dimensions do you mean length and width?
The glass is double pane thickness but I think you mean I might need to add a strut to support that section of the door. Correct?

So do I understand you correctly that a standard lift drum may work instead of a highlight type?
Does my existing standard lift drums have enough room to wind the 120+ in of cable I would need? I have not paid attention to it in a up position to see how much more extra room it had.


Thanks again Ike

Ok, if the weight came from them then it is good.

Doors like that with insulated glass in the top section like that can be a little trickier to spring right, especially in applications like high lift. Spring calculations assume that the door is fairly evenly weighted from top to bottom, but when an disproportionate amount of weight is in one section, it doesn't balance as well.

Standard lift drum might work, but let me look at what the springs do. I will be able to tell fairly well if it will work or not. If you use the standard lift drums, you would use a different length cable. In fact, you would use a cable length that is the same as current plus the amount that the shaft moves vertically. Again, I want to look at this to see if I think it will work in this case. It may not, or at least I may not be comfortable recommending it. Right now, springs are not cheap and are hard to get.

 

[firebirdparts]

This is what I don't understand , if the top of the drum is approx 122" from the floor and the cable is 162" doesn't that mean that 40" of cable will already be wrapped around the drum with the door in the down position basically negating the cone area of the drum? It seems like a lot of he cone section would be gone.

That's what you want. You want a 21 inch highlift and you want 21 inches of the cone actively in use. That is, 21 inches to roll OFF the cone when you close the door. During that final 21 inches, the door is vertical the whole time and the weight held by the cables is not changing. That is what the cone section is for, that situation. You say you want 21" of that. The cone section is 63" total. If you wrap 40" on there that never gets used, then 23" is what you'd actually be using.

 

[general ike]

John than you for your time and effort!!!!

Firebird thanks that is how I understood it as well but with that much cable wrapped you are not using that much of the cone section and I could not understand it since it did no make sense. I now understand that in my application we are barely using much of the high lift design of the drum.
Interesting stuff. Should have paid more attention in the physics class
Ike

 

[general ike]

John, no rush but have you had an opportunity to take a look and see if I can reuse my springs and the existing drums?

I found some pics of the existing springs labels. I don't know what info they might give. I will also be out to the garage this weekend so if any additional info is need I can see what it might be. Thanks again Ike

 

[jstroede]

Sorry I missed this reply. In looking at this, it appears you have a Clopay Coachman series door that is 9x8. It looks like you have unmatched pair springs. I should be able to use the weight and the one spring to figure out the other spring. Let me see if I can fire up my old computer this afternoon and plug some numbers in. Sorry I didn't reply sooner. I didn't get any notification.

John

 

[jstroede]

John, no rush but have you had an opportunity to take a look and see if I can reuse my springs and the existing drums?

I found some pics of the existing springs labels. I don't know what info they might give. I will also be out to the garage this weekend so if any additional info is need I can see what it might be. Thanks again Ike

Can you find any markings on the other spring? Something seems a little off. Even as an unmatched pair, that seems very short for a spring for an 8' high door. If there are no markings on the other spring, can you measure the length of 20 of the coils? That will give me the wire size. Then measure the overall length of the spring.

John

 

[general ike]

John and anyone interested. Thanks for the response. I did not get a notification about your response as well!!

Well some progress, a lot. I spent this weekend moving the tracks and adding the two sections. I also moved the torsion bar to within four inches from the ceiling. The tracks wound up at approximately 9 inches from the ceiling.

I then realized that the door would still be opening the same amount as before and that I perhaps could still use the drums that I had ( or at least attempt to use them). I had the opportunity to make new cables and give everything a try.

It seems to all work fine for the most part. The springs were both wound to 6.5 full turns initially. ( Granted a few years ago I had an issue with the door and I had played with the springs so I am not sure if that is what the installer had set them to.) After some trial and error I set both of them to 8.75 turns. The door goes up nice and easy. But I do have a lot of questions and I am looking for some advise.

First why the asymmetrical springs? Is it that it just did not need two larger springs? Should they be wound the same? Is there a reason one is on the left or the right?

Second I had to move the center bracket supporting the bar from the one side of a centerline to the other. It was cheated to the left all ready by the installer I assume to find a stud. I think that the stud may have splintered in that it would not hold the lag bolts so I cheated it to the right. Does it matter? Does that have anything to do with the asymmetrical springs?

Third a slight issue with the door and spring tensions, at 9 turns the door will just barely creep up and open at the bottom for about 1 to 2 inches when closed but stay open at the top. When I dropped it to 8.75 turns the bottom stays shut but the door just barely sometimes tries to creep down when opened to the top. Nothing I can't live with but thoughts on perfecting it? I have not had a manually opening door in a long time so I am not sure what is normal.

So thanks again to everyone. Thoughts and suggestions?

John I am afraid I did not see your message till late. I measured the whole springs quickly but they are wound. Doesn't that confuse the issue? Sorry I did not measure the 20 coils.

So thoughts? Is it OK to leave as is? Do I need to adjust anything? Have I created a issue moving the center bracket? Have I over wound these springs?

Thanks Ike

Greatly appreciate all the assistance that got me to this point. Excellent forum!!!!

 

[jstroede]

John and anyone interested. Thanks for the response. I did not get a notification about your response as well!!

Well some progress, a lot. I spent this weekend moving the tracks and adding the two sections. I also moved the torsion bar to within four inches from the ceiling. The tracks wound up at approximately 9 inches from the ceiling.

I then realized that the door would still be opening the same amount as before and that I perhaps could still use the drums that I had ( or at least attempt to use them). I had the opportunity to make new cables and give everything a try.

It seems to all work fine for the most part. The springs were both wound to 6.5 full turns initially. ( Granted a few years ago I had an issue with the door and I had played with the springs so I am not sure if that is what the installer had set them to.) After some trial and error I set both of them to 8.75 turns. The door goes up nice and easy. But I do have a lot of questions and I am looking for some advise.

First why the asymmetrical springs? Is it that it just did not need two larger springs? Should they be wound the same? Is there a reason one is on the left or the right?

Second I had to move the center bracket supporting the bar from the one side of a centerline to the other. It was cheated to the left all ready by the installer I assume to find a stud. I think that the stud may have splintered in that it would not hold the lag bolts so I cheated it to the right. Does it matter? Does that have anything to do with the asymmetrical springs?

Third a slight issue with the door and spring tensions, at 9 turns the door will just barely creep up and open at the bottom for about 1 to 2 inches when closed but stay open at the top. When I dropped it to 8.75 turns the bottom stays shut but the door just barely sometimes tries to creep down when opened to the top. Nothing I can't live with but thoughts on perfecting it? I have not had a manually opening door in a long time so I am not sure what is normal.

So thanks again to everyone. Thoughts and suggestions?

John I am afraid I did not see your message till late. I measured the whole springs quickly but they are wound. Doesn't that confuse the issue? Sorry I did not measure the 20 coils.

So thoughts? Is it OK to leave as is? Do I need to adjust anything? Have I created a issue moving the center bracket? Have I over wound these springs?

Thanks Ike

Greatly appreciate all the assistance that got me to this point. Excellent forum!!!!

The asymmetrical pair of springs are generally referred to as unmatched pairs. Some manufacturers will use them to mix and match to reduce the number of SKU numbers in inventory. As long as the total IPPT of the springs is good, and the cycle life is good, then it's fine. The springs should have roughly the same number for turns, though slightly more or less turns on one or the other is ok to tune. The springs are on the left or the right because of the direction that the spring wire is wound. Do not change the side the springs are on!!

The springs can be installed pretty much anywhere along the shaft as long as they fit. They do not need to be centered.

What you are describing is exactly what should happen when trying to reuse your springs. That is probably about as good as you are going to get it without going to different drums or springs. Basically what you would need would be lighter springs that would take more turns in order to help keep the door open at the top. If you are going to use an RJO, you probably want to keep that 8.75 turns, or maybe even down to 8.5. It might also mean taking a quarter turn off of just one of the springs. You can tune it a little by adding say a quarter turn to one spring and take if off of the other. The RJO needs the door to work on gravity, so they need sprung a little heavy.

Measuring the 20 coils just allows me to know the wire size. You have already sprung the door and it is working ok, so this information isn't key at this point.

It sounds like you have it working pretty well.

John

 

[general ike]

Yeah John thanks for the reply, info and the assistance. Working well. I think they might settle in as well. I will wait till next time
out and maybe add a quarter back in in one side to see what it will do.

I can finally get two cars my lift. That frees up a lot of space in the garage to do some work.

Since it is the door in front of the lift it will not be used to any great extent.

Thanks again John and the other forum members for all the assistance!!! Greatly appreciated!! Another project scratched off the list!!!

Ike