Milling Practice


MattF

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4 minutes ago, RichardA said:

No need to trash them, if you are going to work any wood for the next few years, they will always come in handy.

Agreed. They can always be used again - like for breaking down sheet goods.

 

As to your question, I can't say I've ever compared and measured the consistency of different milled boards.  I mill each to where I want it to be and call it good.  If I want more than 1 the same thickness, I run them through the planer at the same setting.

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3 hours ago, RichardA said:

No need to trash them, if you are going to work any wood for the next few years, they will always come in handy.

I will keep them if I can store them somewhere out of the way when not in use.

2 hours ago, Jfitz said:

Agreed. They can always be used again - like for breaking down sheet goods.

 

As to your question, I can't say I've ever compared and measured the consistency of different milled boards.  I mill each to where I want it to be and call it good.  If I want more than 1 the same thickness, I run them through the planer at the same setting.

 

2 hours ago, wtnhighlander said:

Not sure I understand the question. When I mill boards that need to be the same, I mill them all in the same session, and they come out dead-on equal.

This is the approach I took. Milled all boards to thickness in the same session and all 2x4s to width at the same time. For woodworking purposes I would consider them "dead-on equal"

2 hours ago, K Cooper said:

I’ve never thought to check mine, just always figured they were the same. 

I play an engineer at work, I cant help but to measure.

1 hour ago, TerryMcK said:

The thing about general woodworking is that you don't have to work to engineering tolerances. As Ross says mill the boards that you are going to do joinery to in the same session and you will be good to go. For example if making a table frame mill all four legs in one go, then mill all the aprons in one go. The respective parts will all be a consistent thickness relative to each other. They might be a few thou over or under the thickness desired but who cares - certainly not the customer as I've never seen anybody measure my work with a micrometer. and say "this apron isn't exactly 3/4" thick!"

If you hit the boards with a smoothing plane after machine milling to remove milling marks you loose a few thou anyway. 

Use relative dimensioning when matching parts up rather than depend upon absolute dimensions from a drawing and you end up fitting parts to suit. Think of cutting a flush fitting drawer front to fit into an aperture. Cut it slighlty oversize and then mark from the aperture directly onto the drawer front using a marking knife. You will end up with a front suitably cut to fit into the aperture with no measuring done. 

I wasnt trying to hold extremely tight tolerances while milling. To be honest, I didnt even work to a given final dimension for the saw horses, just wanted square material. Out of curiosity I measured the difference for each board to check the variance from piece to piece. I was quite happy with the final outcomes. I'm a manufacturing engineer and by nature I think of the best way to increase throughput and efficiency on everything I do, so batching comes natural. 

 

When it comes to "engineering tolerance", that's a very broad term. I do quite a bit of tooling design and we hold our tolerance extremely tight, +/- .002" over a 36" part is very common in our company. 

 

My original point was not to hit +/- .005" on the final dimensions. I checked squareness, thickness and width out of curiosity.  Mainly because the was the first time I have milled lumber and wanted to check machine and personal work. I was very pleased with the final product. 

 

 

Thanks for all the input.

 

Matt

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1 hour ago, MattF said:

I will keep them if I can store them somewhere out of the way when not in use.

 

This is the approach I took. Milled all boards to thickness in the same session and all 2x4s to width at the same time. For woodworking purposes I would consider them "dead-on equal"

I play an engineer at work, I cant help but to measure.

I wasnt trying to hold extremely tight tolerances while milling. To be honest, I didnt even work to a given final dimension for the saw horses, just wanted square material. Out of curiosity I measured the difference for each board to check the variance from piece to piece. I was quite happy with the final outcomes. I'm a manufacturing engineer and by nature I think of the best way to increase throughput and efficiency on everything I do, so batching comes natural. 

 

When it comes to "engineering tolerance", that's a very broad term. I do quite a bit of tooling design and we hold our tolerance extremely tight, +/- .002" over a 36" part is very common in our company. 

 

My original point was not to hit +/- .005" on the final dimensions. I checked squareness, thickness and width out of curiosity.  Mainly because the was the first time I have milled lumber and wanted to check machine and personal work. I was very pleased with the final product. 

 

 

Thanks for all the input.

 

Matt

Store the saw horses outside of your shop, they'll turn grey but they will still be there when you need them.  I have mine outside for over 5 years and they're still useful when I need them.  Why build new ones every time you need saw horses?

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31 minutes ago, RichardA said:

Store the saw horses outside of your shop, they'll turn grey but they will still be there when you need them.  I have mine outside for over 5 years and they're still useful when I need them.  Why build new ones every time you need saw horses?

I am going to try to hold on to them. Storing outside of the shop in Seattle may not be best. I need a shed for yard tools and other items I want out of the shop. This would be a good place for them. This is on the list for home improvements, but not near the top of my wifes list. With a little rearranging, I can probably find a space for them. 

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2 hours ago, MattF said:

I play an engineer at work, I cant help but to measure.

This may have been an oversight on your part but woodworking is supposed to be an opportunity for you to relax have some fun and forget about things you do at work. ;)

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13 minutes ago, Chet said:

This may have been an oversight on your part but woodworking is supposed to be an opportunity for you to relax have some fun and forget about things you do at work. ;)

No oversight. I am relaxed the minute I step into the shop. Work is not n my mind when its shop time. :DI probably should not use digital calipers in the shop, but I like exact measurements sometimes. I do not use them to chase thousandths on a inch. 

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The old man that taught me, I'm past his age now,  Besides the normal fractions down to 1/64th created his own words for small dimensions. frog hairs and fart skins. 2 fart skins to the frog hair. When he wanted his folding rule, he call for his corn stalk. And he would chant around the house, around the house, behind the kitchen door. He wanted me to get the broom and sweep. The only time small tolerances are considered in my shop is for my tools. One board next to the other just planed needs to be the same by touch. I do not own a micrometer...

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15 hours ago, TerryMcK said:

 

If you hit the boards with a smoothing plane after machine milling to remove milling marks you loose a few thou anyway. 

 

I think this is a key point:  there is always some planing and sanding that occurs before finishing.  "Flat" wood surfaces are never flat to engineering tolerances.

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9 hours ago, Pondhockey said:

I think this is a key point:  there is always some planing and sanding that occurs before finishing.  "Flat" wood surfaces are never flat to engineering tolerances.

The key point of the original post was me taking the opportunity to practice milling lumber for the first time and also build some saw horses for an upcoming project. The tolerances that I stated in the OP are arbitrary and were taken out of curiosity to check consistency of the machines from board to board. I was hoping to compare my numbers with others here to see if the variance in thickness was common. 

The phrase "Engineering Tolerances" seems to keep showing up in the this thread. It appears that most think these tolerances are extremely tight across the board, which in fact they can vary dramatically. This all depends on how critical this feature is. I am a manufacturing engineer and design flat panel satellite antennas in the Ku Band. We have some parts that most features are held to +/- 0.002 over 36". We also have parts that are much loser, +/- 0.010". Tolerances will also depend on the manufacture of the product, mainly for cost reasons. Lets take table saws for example: I have not seen the drawings but I am fairly confident that my Ridgid cast iron top is not held to the same flatness spec as a PM2000. Tolerances will also vary with different engineering fields. 

 

Sometimes I feel that woodworkers sell themselves short in an engineering capacity. If you have designed, drawn and built something, you have engineered it. Granted the drawings are probably pretty basic and missing dimensional tolerances and other all GD&T call outs, but we keep an acceptable level of error in our head and will work off of that. What the level is will vary from person to person and part to part, but we all will work a part until we feel its good to go. 

 

Different Question:

Is there a "too early" to start milling boards for a project? As mentioned above, I am about to start my Ruobo, and the milling will be a large part to tackle. I assume if I mill the boards up one weekend, leaving the pieces slightly oversized,  and glue up the next I should be ok. Most of the lumber has been in the shop and acclimating for about 8 months. I should probably start a build thread for questions like this. 

 

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14 minutes ago, MattF said:

Different Question:

Is there a "too early" to start milling boards for a project? As mentioned above, I am about to start my Ruobo, and the milling will be a large part to tackle. I assume if I mill the boards up one weekend, leaving the pieces slightly oversized,  and glue up the next I should be ok. Most of the lumber has been in the shop and acclimating for about 8 months. I should probably start a build thread for questions like this.

There's another thread going on about this very topic...

 

 

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1 hour ago, MattF said:

Is there a "too early" to start milling boards for a project? As mentioned above, I am about to start my Ruobo, and the milling will be a large part to tackle. I assume if I mill the boards up one weekend, leaving the pieces slightly oversized,  and glue up the next I should be ok. Most of the lumber has been in the shop and acclimating for about 8 months. I should probably start a build thread for questions like this. 

 

I know I may be in the minority here, but sometimes you have to mill a project in stages just because of sheer size. I usually only get a couple of hours at a time. It took me about a month to mill all the boards for the top of my Roubo, since I was jointing by hand.

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I like to partially mill my boards to about 1/16 to 1/8" oversized early on and then mill to final thickness when ready to incorporate into the project.  Reason 1 is to allow mositure content to stabilize and reason 2 1s so I can see the grain - It might affect what piece is cut from what board.

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24 minutes ago, SawDustB said:

I know I may be in the minority here, but sometimes you have to mill a project in stages just because of sheer size. I usually only get a couple of hours at a time. It took me about a month to mill all the boards for the top of my Roubo, since I was jointing by hand.

 

12 minutes ago, Ronn W said:

I like to partially mill my boards to about 1/16 to 1/8" oversized early on and then mill to final thickness when ready to incorporate into the project.  Reason 1 is to allow mositure content to stabilize and reason 2 1s so I can see the grain - It might affect what piece is cut from what board.

Thanks. This was my plan. Just wanted some reassurance that milling too early isn't an issue.

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In my experience  if something doesn't move after a few days or a week it probably won't move after a few months. If you mill and then let the material for the roubo sit for a while you'll see the movement in the beginning and letting it sit longer shouldn't really have much of an impact. This assumes a stickerd or properly ventilated work piece.

I was going to say something about the engineering tolerances as well but you covered it. Tolerances on the projects i deal with are in the hundredths of a foot or 0.12" or 1/8". Even that sometimes is asking a lot.

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Saw horses are also great if you ever decide to do something over-sized. At the shop I worked in before, we had some saw horses and some very stiff beams glued up from a combination of 2x lumber and plywood. They could make a reasonably stiff and flat surface for work support if you wanted to build a large table top, rowboat, or something along the those lines. 

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8 minutes ago, Isaac said:

Saw horses are also great if you ever decide to do something over-sized. At the shop I worked in before, we had some saw horses and some very stiff beams glued up from a combination of 2x lumber and plywood. They could make a reasonably stiff and flat surface for work support if you wanted to build a large table top, rowboat, or something along the those lines. 

The sawhorse were built specifically to be used for the Roubo build. I have a smallish shop, 400 sqft, so unless I can find a storage option out of the way they have to go. Id rather be out $20 in material than deal with moving them out of my way all the time. I am going to take some measurements and see if I have the clearance to suspend them form the ceiling in between the wall and roll up door. 

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2 minutes ago, MattF said:

The sawhorse were built specifically to be used for the Roubo build. I have a smallish shop, 400 sqft, so unless I can find a storage option out of the way they have to go. Id rather be out $20 in material than deal with moving them out of my way all the time. I am going to take some measurements and see if I have the clearance to suspend them form the ceiling in between the wall and roll up door. 

Dare i suggest but can you hit em with a quick coat of paint and store them outside somewhere? You might get a couple more uses before they are unseable espically if you keep the bottms of the legs dry.

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