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Redesigning router sled. Motor size and speed question.

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Forum topic by AZWoody posted 07-26-2017 11:19 PM 1686 views 0 times favorited 14 replies Add to Favorites Watch
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AZWoody

1138 posts in 1057 days


07-26-2017 11:19 PM

I”m going to redesign the router sled I had posted in my projects. It works great but I am getting larger and larger slabs off my sawmill so I need something longer and wider.

Since I’m going to do that, I figured I might replace the router and just get a regular induction motor and mount a collett to it.

My router is a “3.5hp” but what would I realistically need to replace that with if I’m going to get a 220v induction motor for it?
I know that router is not really runing at 3.5hp. Also, what would the rpm need to be?
I’m really considering getting some kind of surface planer but that has carbide inserts.


14 replies so far

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crank49

4026 posts in 2804 days


#1 posted 07-27-2017 12:11 AM

Well, if you are using a 3400 RPM motor, a common speed, you will need to add a belt drive with pulley ratios of 7.35 to 1. The spindle speed needs to be 25000 RPM. While you are at it you better use very good bearings and I might not want to be in the same room with it while it’s running.

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AZWoody

1138 posts in 1057 days


#2 posted 07-27-2017 12:20 AM



Well, if you are using a 3400 RPM motor, a common speed, you will need to add a belt drive with pulley ratios of 7.35 to 1. The spindle speed needs to be 25000 RPM. While you are at it you better use very good bearings and I might not want to be in the same room with it while it s running.

- crank49

I’m not worried on bearings. I know where to get them ;)
Are you sure I would need to go 25k rpm on a bit for surface planing? Those aren’t small bits. The smallest I have is 1.5” and I have a 2” and if I up the motor size, I’ve been thinking 3”.
I was thinking going as fast as a router would be extremely dangers on larger bits.

View TungOil's profile

TungOil

740 posts in 328 days


#3 posted 07-27-2017 01:14 AM

instead of using router bits, try to find one of the molding heads that were commonly used on radial arm saws back in the 70’s. It is sized properly to run at the lower speeds of an induction motor and you will get much wider cuts with that tooling, making your process go much faster.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View ArtMann's profile

ArtMann

678 posts in 650 days


#4 posted 07-27-2017 01:52 AM

If you are using a great big 2.5 or 3 inch bottom cutting bit, you could go with 10,000 or 12,000 rpm. That is what the bit manufacturers recommend. If you turn the bit slower than that, it will cut very poorly due to excess chip loading, regardless of horsepower. If you try to cut faster with more horsepower, you will need to speed the bit up to the 25,000+ rpm that AZWoody mentioned. Those bits are not designed to turn that fast and may be dangerous, as you already mentioned.

If I were trying to speed performance, I would try to design a machine so that the router feeds itself semi automatically. I use my CNC router that way sometimes and it works far better than what I could do by hand.

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AZWoody

1138 posts in 1057 days


#5 posted 07-27-2017 01:53 AM



instead of using router bits, try to find one of the molding heads that were commonly used on radial arm saws back in the 70 s. It is sized properly to run at the lower speeds of an induction motor and you will get much wider cuts with that tooling, making your process go much faster.

- TungOil

That’s interesting. I hadn’t heard of that before. Is there a set of blades that would work for surfacing, or maybe at least a rabbet type knife profile for it? Looks like ebay has quite a bit of those sets for sale.

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TungOil

740 posts in 328 days


#6 posted 07-27-2017 02:02 AM


That s interesting. I hadn t heard of that before. Is there a set of blades that would work for surfacing, or maybe at least a rabbet type knife profile for it? Looks like ebay has quite a bit of those sets for sale.

- AZWoody


I seen to recall that you could get planer knives for them yes. The operation of these things was terribly dangeruous on a radial arm, so be forewarned. I would not attempt to use one of these by hand- you would need to set up some x-y feed screws and crank handles. Like the bed of a milling machine.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

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AZWoody

1138 posts in 1057 days


#7 posted 07-27-2017 02:02 AM

How about running something like this horiznally. Basically having a planer that I move the head, rather than the head feeding the wood under it.

With this, I should be able to use a 1 1/2” induction motor easily enough.

Plus, much of my slabs are very figured and extremely hard woods. This would let me do the top and the bottom and leave them fairly smooth, ready for sanding.

http://www.grizzly.com/products/4-Spiral-Cutterhead/H2877Z?utm_campaign=zPage&utm_source=grizzly.com

My main problem would being able to get the proper rpm as I couldn’t have the pulley any wider than the head size and I could also only run it in one direction. The direction would be a trade off though in that I could have a surface that has much nicer results.

View TungOil's profile

TungOil

740 posts in 328 days


#8 posted 07-27-2017 02:08 AM



How about running something like this horiznally. Basically having a planer that I move the head, rather than the head feeding the wood under it.

With this, I should be able to use a 1 1/2” induction motor easily enough.

Plus, much of my slabs are very figured and extremely hard woods. This would let me do the top and the bottom and leave them fairly smooth, ready for sanding.

http://www.grizzly.com/products/4-Spiral-Cutterhead/H2877Z?utm_campaign=zPage&utm_source=grizzly.com

- AZWoody


that’s shaper cutter, and a big one. I would not use that since the forces of the cut are all in one direction. If it gets away from you it will take off like a dragster. stick with a rotary cutter, it will be safer.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

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AZWoody

1138 posts in 1057 days


#9 posted 07-27-2017 02:13 AM


How about running something like this horiznally. Basically having a planer that I move the head, rather than the head feeding the wood under it.

With this, I should be able to use a 1 1/2” induction motor easily enough.

Plus, much of my slabs are very figured and extremely hard woods. This would let me do the top and the bottom and leave them fairly smooth, ready for sanding.

http://www.grizzly.com/products/4-Spiral-Cutterhead/H2877Z?utm_campaign=zPage&utm_source=grizzly.com

- AZWoody

that s shaper cutter, and a big one. I would not use that since the forces of the cut are all in one direction. If it gets away from you it will take off like a dragster. stick with a rotary cutter, it will be safer.

- TungOil

I agree with you on that. I would have to have a motorized feed on it, which I really wasn’t wanting to do. Just thinking out loud really. If I can find the planer head on that radial arm head, I think that would be the ticket.

Do you know by chance the HP rating on the radial arm saws that would run that?

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TungOil

740 posts in 328 days


#10 posted 07-27-2017 02:34 AM


Do you know by chance the HP rating on the radial arm saws that would run that?

- AZWoody

Radial arms saws, like table saws, came in all different HP. more power = higher feed rate. higher HP induction motors get quite expensive as well.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

View KelleyCrafts's profile

KelleyCrafts

2680 posts in 573 days


#11 posted 07-27-2017 09:01 PM

I think you just need a 36” jointer to sit next to the 16” and 20” you already have. Or just take the fence off of one and snug the jointers close together. ;)

-- http://kelleycrafts.com/ - pen blanks - knife scales - turning tools

View ArtMann's profile

ArtMann

678 posts in 650 days


#12 posted 07-27-2017 09:10 PM

Back in the early 1980’s, I used to have a Craftsman 3 knife molding head, which I think is what we are talking about. I used it extensively for exactly one job. I built the columns in this picture using beveled fir 2X4 segments that were partially machined on it.

I used it on my craftsman 1.5 horsepower radial arm saw and the power was quite adequate. I pushed the work piece across the rotating head that was oriented horizontally. That is one of the scarriest woodworking jobs I ever did. The set included planer knives like what has already been mentioned. The problem with using one of these is exactly the problem you will have trying to run figured wood across a straight knife jointer. You are going to get all kinds of ugly tear out. A big router bit rotating at the correct speed won’t do that.

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eflanders

218 posts in 1684 days


#13 posted 07-28-2017 02:00 PM

FYI I think I saw in the Infinity catalog specially designed router bits for planing wide stock. Best to confirm this with them though… I’m not sure what their advantage is but it might be something to consider?

View Andybb's profile

Andybb

543 posts in 437 days


#14 posted 07-28-2017 07:07 PM

I’d be worried about safety with a DIY machine with a heavy duty motor. This is what I use in my router sled. For big slabs I take them to a mill here in town and it costs me $80 to flatten and sand to 120 grit in about an hour.

-- Andybb - GO HAWKS!

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