Kickback Incident

dusty · Post by **dusty** » Tue Dec 01, 2009 2:18 pm

With the season coming on and the recent discussion on potential safety hazards, I was forced into action. I am hoping that this will satisfy my production schedule while at the same time improve Table Top Safety.

Feedback Please - positive and negative!

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heathicus · Post by **heathicus** » Tue Dec 01, 2009 2:32 pm

That's a great looking sled, Dusty! The only danger I could see would be the exposed blade behind the sled as the back of the sled passes the blade. But that might be picking nits.

dusty · Post by **dusty** » Tue Dec 01, 2009 2:39 pm

heathicus wrote:That's a great looking sled, Dusty! The only danger I could see would be the exposed blade behind the sled as the back of the sled passes the blade. But that might be picking nits.

No, that is a value criticism and appreciated observation.

You know that feeling (small voice) that has been mentioned. I sorta felt (heard) same when I was testing this. That may be the reason for the sensation.

I don't want to trade one reason for cutting off a finger for a different one.

robinson46176 · Post by **robinson46176** » Tue Dec 01, 2009 2:41 pm

[quote="dusty"]With the season coming on and the recent discussion on potential safety hazards, I was forced into action. I am hoping that this will satisfy my production schedule while at the same time improve Table Top Safety.

Feedback Please - positive and negative!

Do you think it is heavy enough?

You are to be commended for quick action. I have been procrastinating on mine for over a year.

Looks good, just be careful about the blade coming through the push bar and trimming your thumbnails.

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If you take a small corner off of the bottom of the stop block (maybe about 1/4" to 3/8" high it will keep sawdust from piling up against the end of the stop block and getting compacted into a accuracy destroying lump.
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"Somewhere"... (maybe even PTWFE) I saw plans for a sled that you also used for all manner of angle cuts etc. I have a book of "Jigs & Fixtures" here "someplace" (dang I say that a lot). Maybe that was where it was. I'll look tonight. I recall one that used swinging stops to make the angles and another where you just cut angled blocks and dropped them in place where they were held with guide pins for accurate angle cuts.

mickyd · Post by **mickyd** » Tue Dec 01, 2009 4:00 pm

dusty wrote:With the season coming on and the recent discussion on potential safety hazards, I was forced into action. I am hoping that this will satisfy my production schedule while at the same time improve Table Top Safety.

Feedback Please - positive and negative!

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Great piece of work dusty. Very professional. Adding the little guard box in the back to keep the little voice quite will complete the job, unless you plan on putting 10 or so coats of spar on it.....I have extra you know.

dusty · Post by **dusty** » Tue Dec 01, 2009 4:08 pm

Thank you for the input. I have incorporated two quick changes.

The stop block has been champhered on two edges to reduce unwanted interference by saw dust accumulation.

A dog house has been added to the back side of the fence. This will prevent blade exposure at the end of the cut.

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PS Really ugly glue job. It is too late now but I really should have cleaned up the dog house while I could do it on the belt sander. Now it is a hand sanding job. Not smart. This is sorta like accidents - the direct result of haste.

JPG · Post by **JPG** » Tue Dec 01, 2009 4:58 pm

robinson46176 wrote:OK, I'm going to throw this statement in here... I don't believe that there is good basic comprehension here as to the amount of lifespan being taken off of the Shopsmith (or any power tool) by constantly starting it up over and over again, especially something that that starts as hard as a Shopsmith does. Just because you do not see or hear an immediate effect doe not mean that you are not shortening its life. Many successive start-ups close together are far harder on it than the same number of start-ups spread out over longer time. Heat will build up in the plug, the power cord, the main switch, the centrifugal starter switch, the capacitor and the motor windings much more than just running. The more heat that builds up the higher the electrical resistance will build up which in turn generates more heat...
You should not hesitate to shut it down when needed for safety reasons but to "plan" to stop / start a whole bunch of extra times one after the other as part of daily use is in my opinion a poor plan especially when there are many other better options available.

Well said! There are two reasons for turning the speed down prior to 'shutting off'. As owners of 3/4 HP models are quite aware of the act of starting up when set to higher speeds does take its toll on the motor. It takes a lengthy amount of time to 'get up to speed' which greatly increases the heat buildup to which Farmer has already mentioned.
The second is the possibility that a sudden jar or the vibration of moving the SS around with the sheaves in their 'high speed' positions will momentarily cause the control sheave to 'open up' and allow the belt to drop further into the spacing(possibly enough to cause it to jam). Even if it doesn't jam, the added torque required to start up with the belt 'out of round' may stall the motor or at least greatly increase the time and torque required to get it 'running'.

If you are ever considering purchase of a NEW SS, get the 230V 60Hz version. They start very quickly at high speed and draw half the current! I am assuming the power-pro is not an option. Also as recently 'discovered' there are 50 Hz models 'over there' which have different upper poly-v pulleys! An additional consideration if 50 Hz may be in your 'future'.

nomoman · Post by **nomoman** » Tue Dec 01, 2009 5:24 pm

dusty wrote:Really ugly glue job. It is too late now but I really should have cleaned up the dog house while I could do it on the belt sander. Now it is a hand sanding job. Not smart. This is sorta like accidents - the direct result of haste.[/SIZE]

What is a dog house? I know the big one in the backyard, but not of the one which Dusty mentions.

JPG · Post by **JPG** » Tue Dec 01, 2009 5:39 pm

nomoman wrote:What is a dog house? I know the big one in the backyard, but not of the one which Dusty mentions.

The dog house to which he referred is the ugly glue job appendage he added to the 'front'(the push bar) of the sled so that the front of the saw blade would not be exposed as the cut is 'finished'. See the last pix!

dusty · Post by **dusty** » Tue Dec 01, 2009 6:04 pm

nomoman wrote:What is a dog house? I know the big one in the backyard, but not of the one which Dusty mentions.

otherwise referred to (by me) as the doghouse.

As JPG has explained, I hung this on the back so that the blade was less likely to be exposed when the sled was pushed way forward during a cut. Suppose to prevent an unplanned manicure.

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It (the sled) still needs some finish work but I sorta think this is a prototype. I have done several things that I would want to revise before I called it "my design" and "finished".

Like most all of my projects, I change more details on the fly than were planned to start with. Most of my projects, especially the successes, are real surprises.

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