Help cutting moulding

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thehadmatter

CGF, Certified Grumble Framer
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Oct 19, 2007
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Central USA
Before I ask my question I feel I should explain our set up. When I was approached about coming to work for the frame shop I am in now I had minimal experience in framing, learned it in college 15 years previous. That was not a hinderance for my employer, he was hiring me as lead designer/sales clerk and I was wisked away to a beginner workshop the first month on the job. I have since attended two more workshops. I can design, sell and am learning all the specifics about preservation techniques. However, the one task I have not learned is how to cut mouldings. I know that each moulding has a varying allowance and I am assuming it is based on width and height. I have had to teach myself on the fly a couple of times. But I would like to find out if there is a chart somewhere or a rule of law in finding what allowance should be given to mouldings. I would like to broaden my knowledge and experience in framing and this would help me a great deal. The gentleman who cuts our frames is elderly and won't be around forever. We have talked about me learning the ins and outs of cutting, but it hasn't happened yet. I am worried I will be left at some point without assistance and without a clue and without a warning. Anyone have suggestions for me? I feel very ignorant asking this question but know this is the place to ask without being criticized. Thanks for the help all!
 
It's static at 1/8"

IE, a 16 x 20 frame measures 16 1/8 x 20 1/8 inner dimensions. Width or height is irrelevant.
 
As already stated the standard allowance at the inside rabbet is 1/8".

If you are trying to figure out how many lineal foot of moulding is needed then you do have to also take the width of the moulding into consideration. For instance a moulding that is 1" will wide need an additional 8" or a 2" moulding needs an additional 16" (width x 8 corners) In reality you also need to allow a little more for waste.

Most of your supplier catalogs have a conversion chart in them. You read the united inches of the frame (16x20 = 36) then find the width of the moulding in the chart and read down to find the lineal footage needed. Most POS systems do this for you automatically also allowing for some waste (not talking about the need to cut around defects)
 
Right I knew standard allowance is 1/8. However, for example, I had a metal moulding that needed 1". Aren't there others that require variances?
 
thehadmatter said:
Right I knew standard allowance is 1/8. However, for example, I had a metal moulding that needed 1". Aren't there others that require variances?
Click to expand...

Not if you're cutting the rabbet measurement - standard in the framing industry. The only common variation is 3/16" (or 1/4") allowance for canvases.
 
j Paul said:
Most of your supplier catalogs have a conversion chart in them. You read the united inches of the frame (16x20 = 36) then find the width of the moulding in the chart and read down to find the lineal footage needed. Most POS systems do this for you automatically also allowing for some waste (not talking about the need to cut around defects)
Click to expand...

I believe what jPaul ment to say here is (16 + 20 = 36) You have to add the side not multiply.
 
It's a good idea to allow more elbow room on large canvases. If they go slack and need re-tensioning, a 48x36 canvas can 'grow' 1/2". Sometimes it is necessary to either add a fillet or slip to widen the rabbet or take an extra bite out the back of the rabbet with a table saw or router.

On very small oils I find it is better to work to the sight size. That is, the extreme inner edge of the frame rather than the back of the rabbet. Otherwise a 7x5 oil can become a 6x4.:icon11: Scraps of foamcore can fill the gap and hold the oil in place.
 
As long as you're measuring from the rabbet, usually the allowance is 1/8. You normally don't need more than that. On canvas I use even less--about a 1/16th.

What type of measuring system are you using? Your employer may be using the old school measure mark and cut method...a lot harder...but some people are great at it.
 
What kind of cutting equipment do you have and what is your proceedure for cutting?
 
Metal frames will vary by size. Sounds like you are using a double miter saw and measuring to the outside rather than the rabbit which is difficult with metal.

I don't sell any metal any more but for example the ouside of a simple metal (#5, #11, #15) is 1/4". The others depend on the brand and style number. Call the supplier you buy from and they will tell you for the various profiles.
 
Dimensions.jpg


There are three dimensions that we commonly encounter:

Frame Dim. – the maximum, overall frame size which covers the wall

Sight Dim: – the interior, “viewable” dimension through which you see the mat, art, glass, etc.

Rabbet Dim: – the dimension “under the lip” into which the glass, mats, art, etc., are secured into the frame.

Ninety-nine percent of the time, we are concerned with this rabbet dimension. It is the one used to measure and cut mouldings, both wood and metal (and plastic).

Most often, mouldings are cut witht a 1/8” “allowance” on most frames; sometimes 3/16” for stretched canvas, but seldom more than that.
 
Maybe I didn't make my question clear. I know we allow 1/8" allowance on the frame. But let's say, I have a double rabbet frame that needs to measure 16 x 20. We would want those legs to measure 16 1/8 x 20 1/8. But when cutting on the saw, and we do not have a double mitre saw, I would not set that length at 16 1/8 in every instance because some will not come together properly if I did that. I know that in a couple of instances, like the metal I mentioned, I had to set my measurement at 15 1/8 in order to get the final true measurement of 16 1/8 and the legs all come together properly. This is the "allowance" I am referring to. I hope that is just as clear as mud.
 
I don't know about everyone else out there (I'm sure most do the same as me) but I for one cut to 1/8" over actual length. I have a scale (ruler) on my chopper and it is dead on. No reason to make allowances.
 
I've never heard of anything like that on a metal frame. The only way possible that I can think for this to have happened is that you didn't line up the proper point of your moulding with the line on your scale. Inside the rabbet, which is right up next to the metal outer wall on many narrower metal frames, is where you measure from.

My rule: regardless of what you are cutting, always measure to where the art will touch the moulding. On stretcher bar, you measure to the outside of it, on thin metal mouldings, you measure to the inside of the outer wall, and on wood mouldings you measure to the inside of the rabbet.

As for variations in where to cut to get the proper 1/8" allowance, I tend to cut narrower (under 3/4") mouldings a hair less than the 1/8" allowance scale mark, and I tend to cut wider mouldings (> 3") a hair over the 1/8" allowance scale mark. When you take a ruler to it afterwards, I get the 1/8" allowance I need that way on all mouldings. Personally, I think the reason for this variation on my cuts is that my single mitre saw is not quite perfectly calibrated, or perhaps my scale lines are not quite pefectly 45 degrees from the horizontal.

One other thing. Several people have indicated that they use 3/16" or 1/4" allowances for moulding for canvases. I never do that. What if they bring the frame back to swap it onto a standard size photo? You run into issues that way. Instead, I always cut my stretcher bar 1/16" less than the indicated size. That allows the canvas itself to actually take up the 1/16" and bring the painting to the proper size. The folds in the corners make make it a tad bigger, but the normal 1/8" allowance in the frame is there to take care of that.
 
Ok, there is no standard difference for each metal profile. The reason you are subtracting an inch is based on a mathematical equation. If you look at where you are measureing on your moulding when you cut a wood frame, and compare that to where you are reading your measurement on a metal frame, you will find that what you are actually doing is subtracting that difference twice, once for each mitre. It works differently based on which saw and fence setup you have, whether the moulding moves along the fence facing in or out, where you are lining up your measurement on the ruler (on the outside edge? on the rabbet?)

So....
\What saw are you using? If you are unfamiliar with the equipment can you describe it? Does it have two blades that come down and cut both sides of the mitre simultaneously, then run the moulding with the outside edge along the straight fence to the desired measurement? Or is there a single stationary blade with a fence at both sides set at a 45 where you cut one mitre, then move the moulding to the other side with the rabbet along the fence where you measure your next cut? The formula for the difference between metal and wood is different based on what you are using. Once you understand the formula, you can make it work with any profile.

Is the fence set up to where you add the allowance to your size, or is it automatically worked in so that you set it to 16" and it comes out 16 1/8"?

Do you have a moulding number for the metal frame you are cutting so we can figure out this formula?
 
The metal frames have a channel that hold the art in the back so the rabbit is not against the measuring arm. That is why you had to cut shorter to get the longer size.

Tell us about your setup on the saw. Is the moulding against a guide on the rabbit side or the outer side of the moulding.
 
I’m confused, too.

When you say, “double rabbet” are you referring to

DoubleRabbet.jpg
?

If so, ignore it. The depth/width of each “double rabbet” may be different. Measure only the actual “where you drop your mat, glass, art, etc.” rabbet. It may require you to drop an imaginary vertical line from this rabbet to the cutting table, but measure and cut from this rabbet dimension.
 
I think imaluma has it, although I am a bit confused as well.

Allowance is wiggle room.

To properly size a metal moulding, you subtract from the size of the package (Mat and glass) two times the width of the back of the channel, that would be the part that gets the brackets and touches the wall. Measured from the inside of the channel. On your average nielson or clark, that space is 9/16, so you subtract 1 1/8" from the size you are trying to build.

For a double rabbet, you add two times the distance between the rabbets usually, because the second rabbet is sitting on the measuring arm and that's not what you're trying to cut to.

The wiggle room is usually built into the saw, so if you cut 16", the leg is actually 16 1/8, so you don't need to add it to your equation.

Other than that, I don't do math when I cut, I just set my production stop. That's on a Framesquare mitre saw which cuts one mitre at a time and then you switch to the other side.
 
Kind of lost me - that's not unusual though - probably because I haven't sold a metal molding in the last 5 years and I can pretty much guarantee that I won't sell one in the next 5 years, if I can help it. I don't care for the metal mouldings and haven't found one yet that I like the looks of enough to change my opinion and I have found that if you don't care for something it is really hard to be positive enough about it to sell it - besides, I have never seen a metal moulding in a class act museum, there are probably some but I can't remember seeing them.
 
MabSadie2 said:
The wiggle room is usually built into the saw, so if you cut 16", the leg is actually 16 1/8, so you don't need to add it to your equation.
Click to expand...


The allowance is either added when cutting or already there depending on how the saw/fence is set up. We wouldn't want to coerce anyone to not consider it, if their circumstances and equipment warrant consideration.
 
Joe B said:
Kind of lost me - that's not unusual though - probably because I haven't sold a metal molding in the last 5 years and I can pretty much guarantee that I won't sell one in the next 5 years, if I can help it. I don't care for the metal mouldings and haven't found one yet that I like the looks of enough to change my opinion and I have found that if you don't care for something it is really hard to be positive enough about it to sell it - besides, I have never seen a metal moulding in a class act museum, there are probably some but I can't remember seeing them.
Click to expand...

Joe ...I too don't care for metal in 99.9% of the cases, but you shouldn't totally close yourself off to offering some. What do you say to the customer who does want a metal frame???

Besides ... metal = money.

Also ...it is OK to be a framing snob. Just don't put more than one clothespin on your nose when you sell metal.

:party:

Easy and profitable.
 
Dave, thanks for the advise. I do have some samples on the walls (about 12) but I none of my customers have been to demanding about the metal and I have been able to steer them all to wood so far. My shop is really small so I don't have a saw and would have to order any metal molding chopped. In the end the cost of the metal mouldings at chopped prices are more expensive than equal wood mouldings so it is a easy sale and the customers all believe they are getting upgrades for a less price. I wouldn't turn away the business if they absolutely wanted the metal moulding but that hasn't been the case in a super long time and I can't see how that will change in the future unless some really dinamite metal moulding comes out.
 
All of these crazy math calculations are alot of extra work for no reason!! Who taught you to do it that way??

I can say with all confidence that I measure and cut metal AND wood frames the same way. My measuring rails were set by me for an exact cut when I set the saw up and haven't changed since. If you have a system that doesn't allow you to get a consistent exact size , then you need to consider upgrading to a system to allow that. It makes work so much easier.

There is no multiplying or subtracting. If you want 16", the standard allowance is 1/8" so you would set the rabbet on the 16 1/8" mark and cut. On a metal frame, the place you set your measurement is the inside of the frame which is the back of the rabbet. What is so hard about that?
Personally, your saw should not be set to include the 1/8" allowance because there will always be times when you want either an exact cut size or a little larger size and it is just easier to make those little adjustments from the size you start with.
There might be a time when you are not the one cutting and they might not know about your little allowance adjustment or not remember.
Always set the measuring rails to an exact measurement .. with NO allowances!! .. and that will lessen the chances of mistakes.


...and no... hadmatter..so far you haven't been clear about what you are talking about, so what you are saying is still confusing and makes no sense.
Please try again to describe.
 
By the way.. there are some dynamite metal mouldings out there!!
Why would you always want to sell your customers down on price??
sounds like you are leaving money on the table so to speak.

Alot of pieces look quite nice in a metal frame and realize that a persons house is not equal to a museum so that analogy doesn't work here.

There are times where a thin line of color works nicely and a metal frame is the only place to get that color.

So, get rid of the clothes pins and get yourself a set of metal samples including the nice new ones.

Make more money!!
 
I'm with framah on this. I set up my saw with the exact measurements, so a 16" is a 16"
I don't understand exactly what you're asking either as you seem to know the allowance of 1/8 or whatever you decide which allowance to use.

I order my metal frames chopped. Yes, I do loose a bit of profit, but to me it's not worth doing it myself. I do have customers that want the specific color or the narrow frame look, where wood wouldn't do it. So again, there is a market for that, even if you don't care for metal. But have you checked out the new lines NB has now? There are some gorgeous metal frames that wouldn't look wrong in a museum! (and not everyone lives in a museum). Also, it does work for quite a few contemporary pieces. So don't dismiss metal, based on metal frames from the past. Check out the new ones!
 
Must be a New England thing!!:beer:
 
Framah, Thank you for the advice, I will be looking at the NB line this weekend at the TC Moulding show.
As far as leaving money on the table - no don't believe so - a $6.00 a foot moulding is a $6.00 a foot moulding no matter if it is metal or wood. Profits are the same because my markup is the same for both mouldings. Now the other way to look at this is if my customer is only willing to spend that same $6.00 where will they be getting the better value; as an example, my $2.00 a foot wood moulding that I paid $2.00 for or my $1.00 a foot metal moulding that I had to pay $2.00 a foot for because of the chop cost; IMHO that is a no brainer, but, no matter the profits are the same. Personally, I don't like metal mouldings and don't sell it because I have no need to, believe me I have thrown the clothespins away a long time ago, I'm just looking at economics and how best to satisfy my customers. If my customer is dead set on metal moulding that is what they will get, I just haven't been in the position to have to sell them metal in the past 5 years and don't know why that will change in the future.
 
Framah, some systems are set up so you can't just visually line up the back of the metal frame rabbett to the measureing rule, as in a framesquare saw. In this case, the first mitre is cut and then moved to the other side of the saw and the lines on the measureing rule are parallell to the mitre, not perpendicular so you are lining up the flat of the mitre to the measurement rather than the point where the rabbett meets the line. On these setups it is impossible to just line up the inside of the frame, and the only way to do it is by mathematical equation. It's easy enough to tell someone to get a different saw to make their work easier, but that is easier said than done. I am less concerned with berating a person for not updating their equipment to someone else's standards than I am with trying to help out someone who is a new(ish) employee at a shop, who is not being given to most thorough training possible, and who is stuck using the equipment that exists there.

For all we know this person could just be using a pistrious and is just lining up the inside of the hardware channel instead of simply visually lining up the inside of the frame. I hope this is the case. But if he/she (?) has not been trained on the equipment properly to know the difference then we may not be of much help at all anyway.
 
Maybe I missed the answer somewhere along the way, but I think the OP was looking for a way to figure out the Outside Dimension (OD) based on the width. If that is the case, you need to add 2 x [back width*] to your Frame Dimension plus Allowance to get OD.

If you have a fence system designed for cutting 45° angles such as any typical picture framing system there is no need for this. If you are using a contractor type fence with only measurements at the back of the fence, and no angled lines on the bed you will need to do the OD calculation, or measure and mark the rabbet and cut to the mark.

*the difference between Frame Dimension and Outside Dimension.
 
Bill Henry- said:
Dimensions.jpg


There are three dimensions that we commonly encounter:

Frame Dim. – the maximum, overall frame size which covers the wall

Sight Dim: – the interior, “viewable” dimension through which you see the mat, art, glass, etc.

Rabbet Dim: – the dimension “under the lip” into which the glass, mats, art, etc., are secured into the frame.

Ninety-nine percent of the time, we are concerned with this rabbet dimension. It is the one used to measure and cut mouldings, both wood and metal (and plastic).
Click to expand...

Bill,
I'm not sure where you got that picture and/or description, but it conflicts with FACTS Standard FRM-397. Using that standard,
your "Rabbet Dimension" = FACTS "Frame Dimension" and
your "Frame Dimension" = FACTS "Outside Dimension".

While I recognize that FACTS doesn't have any jurisdiction over anyone it would seem a real waste for it to be ignored when such efforts have been put into it and there is no reason (that I know of) to not use it, i.e. it does not conflict with any other standard that I'm aware of.
 
Sorry, one more observation. Though not germane to the OP (at least, as I interpret the OP) it did come up in the conversation.

While 1/8" is indeed the "Standard Allowance" it is up to the framer to determine if the standard is applicable in the application. FACTS also has a standard that addresses evaluation and selection of an allowance.
 
This is what I am talking about with the framesquare, and how it differs from a straight line fence, like on a pistorius or a morso. The moulding gllides along the fence facing in and the measurement is read along the mitre. Fig 1 shows the basic setup of the saw, fig 2 shows how "normal" and easy it is to measure a wood frame, because the rabbett is the point that meets the fence and ultimately gets measured. Figs 3 and 4 show how on different metal frames the point that meets the fence is NOT the rabbett, and describes where the difference is that needs to be subtracted based on teh profile. It is not standard by any means but many profiles are the same underneath and I'd bet ducats to dollars that the reason the OP was trained to take off an inch was that the metal profiles being used are the ones commonly used in poster packages like 11, 15, 05, etc. which measure exactly the same where it counts, and the other profiles are not being designed as much since the poster package tends to be a fallback sell and that is usually when design shifts from wood to metal. Excuse the sloppy drawings. I hope it makes sense. But without a lot more information from the OP I am only guessing at the relevance of this anyway.

001.jpg
 
Nice drawing, Imaluma... suitable for framing!
;) Rick

P.S. Notwithstanding personal preferences, I believe that eliminating metals as a design option is cutting off one's nose to spite the face. Sure, many are pedestrian looking. However, there are some very distinctive profiles that give beautiful, contemporary, clean and classic looks to the right kind of art. They also combine nicely with woods in stacked designs, providing the bonus of an acid barrier within the rabbet. If you haven't kept up with what's new in metals, you owe it to yourself to check out Nielsen's "Gilded" series, featuring finishes and patterns formerly found only on woods- enabling you to use a trim profile safely on a large piece; and the "Natural Elements" series that has various molten metal finishes applied over the aluminum substrate. They are unique, providing effects found nowhere else on any kind of moulding. BTW, I am not a paid spokesman for Nielsen or anyone else except my own business.
 
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