Help needed, Craftsman wood planer.

[tonyfoale]

I have a small and very old cast iron Craftsman planer which I bought at a yard sale when I lived in the US. Other than a "don't cut you fingers off" notice there is no other info with it. The table is 4 or 5 inches wide and the drum is a touch over 2" diameter with 3 blades. The spindle looks as it it runs in plain bearings but I have not dismantled it yet.
Does anyone know what RPM the spindle should spin at? Failing that, can anyone give me a guide to surface cutting speeds for wood, Google came up with a lot of useless info, many planer users seem to be confused between cutting speed and cutting feed.

[bruce.desertrat]

You might peruse this page Sears | Craftsman - Photo Index | VintageMachinery.org to see if you can ID it. If you can find the craftsman part number on it you may be able to track it to the OEM and that site has tons of old manuals.

Also, your description sounds much more like a jointer than a planer...4-5" wide would be quite narrow for a planer. The link above also lists numerous jointers,

[tonyfoale]

You might peruse this page Sears | Craftsman - Photo Index | VintageMachinery.org to see if you can ID it. If you can find the craftsman part number on it you may be able to track it to the OEM and that site has tons of old manuals.

Many thanks. I have identifird it as a Sears Roebuck 149.21871. It is a couple of decades younger than I thought at 1970s/early 80s. Anyway I couldn't find anything on that site to answer my question. Actually my question isn't really machine specific, cutting surface speeds depend on material to be cut and maybe material of the blades. In the absence of additional information I'll aim for around 12,000 rpm which should give conservative cutting speeds. If the bearings/bushes wear out I'll modify it to take ball bearings.

Also, your description sounds much more like a jointer than a planer...4-5" wide would be quite narrow for a planer. The link above also lists numerous jointers,

It is listed on that web site as a jointer, but I can't figure out what sort of joints you would make with it. To me it looks like a small machine to plane with. I could be very wrong but I think that jointer is likely to be the US term only, but although I have done some pattern making in the past I am not an habitual woodworker.

So what exactly is the difference between a jointer and a planer?

[Imbeciliac]

So what exactly is the difference between a jointer and a planer?

A jointer is used to provide one straight edge on a board, often in preparation for joining several boards together, which is why it is sometimes called an ‘edge jointer’. The other edge is usually then cut on the table saw to provide a parallel edge to the jointed one. A planer usually employs a much wider cutting head (unless your jointer happens to be a massive industrial version) and is used to plane (obviously) the sides of a board, not only to smooth the surface but also make both sides parallel, and to reduce the thickness, which is why it is often referred to as a ‘thickness planer’.

Hope that helps demystify the names.

Edit: Damn. Haroun beat me to it.

[suther51]

When i get a chance I will look at a book I have that is a collection of articals from the us forest service, there Is a section on jointing planer blades, it may have a some info on surface feet per minute of cutter blades for wood. Barring that I have an old Montgomery wards joiner with what might be a similar size head in it to use as a referance. As long as you do not drive the cutter head so fast that you burn the knives (heat to the point of drawing the temper) the rpm is not overly critical in a non production situation. The wadkin molders where I used to work would jam and stop feeding, the knives would burn real fast. The finish of the molding stock would suffer as a result. In the neighborhood of 1725 rpm may be good if i remember that the pulleys are of equal size on my 6 inch jointer. Hope you find your answer.
Eric

[Al8236]

Many thanks. I have identifird it as a Sears Roebuck 149.21871. It is a couple of decades younger than I thought at 1970s/early 80s. Anyway I couldn't find anything on that site to answer my question. Actually my question isn't really machine specific, cutting surface speeds depend on material to be cut and maybe material of the blades. In the absence of additional information I'll aim for around 12,000 rpm which should give conservative cutting speeds. If the bearings/bushes wear out I'll modify it to take ball bearings.

Do not try to run the cutterhead at 12,000 RPM! you are going to want about 7,000 RPM max with a machine with bushings rather than roller bearings. those high speeds will just tear up the machine You probably want to double your motor speed, In the States it would be 3450 RPM @ 60hz. in Europe running @ 50hz. will run a tad slower

[tonyfoale]

Do not try to run the cutterhead at 12,000 RPM! you are going to want about 7,000 RPM max with a machine with bushings rather than roller bearings. those high speeds will just tear up the machine You probably want to double your motor speed, In the States it would be 3450 RPM @ 60hz. in Europe running @ 50hz. will run a tad slower

i have a Hitachi powered hand plane which states 14,000 rpm and which I measured to be 12,900 rpm unloaded. It has an OD across the blades of 64 mm. The Sears/Craftsman is 54 mm. So the surface speed of that at 12,000 rpm will be 72% of the manual plane. That being the case I am unsure as to why you warn against that speed. As I mentioned, if the bushes are not up to the job I can easily convert to ball bearings unless there is something that I'm missing. The limit as far as I can see is heating of the blades.
Is there any reason that eludes me that lets a manual machine spin around double that of a fixed machine?

[Al8236]

I just went out to the shop and looked at my power hand plane and my craftsman jointer the hand plane runs at 12,000 RPM with about a 2 to 1 reduction to the cutter head and the jointer runs a 3450 RPM motor with a 2 to 1 Increase to the cutterhead. that is what I am going by. Do what you will but I don't think the jointer was ever intended to operate at those speeds.

[hemmjo]

I think that cutter head would run in the 4500-5000 rpm range. Feed rate depends a lot on the specie of wood, grain structure and moisture content of the board, as well as sharpness of your blades and the capacity of your system to clear chips. Typically planers with variable feed rates range from 0 fpm to 70-80 on the high end for big industrial machines. Fixed feed rate models run between 15-30 fpm

With a 3 blade cutting head you have 15,000 cuts per min @ 5000 rpm. If you feed stock at 10 fpm you have 120 in / 15000 cuts or .008" per cut. As you know, it is all a balance between the speed your cutter head bearings can handle and the power your motor can deliver relative to the feed rate you choose.

I just looked at some specs online for new models, they range from;
Grizzley 8750rpm 3 blade with 26 fpm feed rate
WEN 9000rpm 2 blade with 26 fpm feed rate
DeWalt, 10,000rpm 3 blade, no feed rate given but they claim 96 cuts per inch so that would be about 31 fpm feed rate

None of these specify cutter head diameter.

Not sure if it of any assistance, but there some info from state side.

John

[tonyfoale]

i just found this on Wiki
"A jointer or in some configurations, a jointer-planer (also known in the UK and Australia as a planer ......."

I was born in the UK and grew up in Australia, so for me it's a planer.