Newby with another project

[Crusarius]

try this

Amazon.com: KIPA Belt Tensioner Assy Fit for Toyota Camry Rav4 Highlander Sienna Scion Tc Lexus ES RS OEM Part Number 16620-36010 16620-0V020 : Automotive

let me know how you mount it so I can mount mine

[JoshNZ]

Mine just has a piece of angle iron with a slot machined in it, welded vertically to the beam. The pulley shaft can slide vertically in that slot and the shaft has a threaded stud on it that tightens it up from moving. I just lever the pulley up into the belt with a block of wood until it's tight then torque up the nut on the stud

[Cornerstone]

Mine just has a piece of angle iron with a slot machined in it, welded vertically to the beam. The pulley shaft can slide vertically in that slot and the shaft has a threaded stud on it that tightens it up from moving. I just lever the pulley up into the belt with a block of wood until it's tight then torque up the nut on the stud

THIS. 

[rusticretreater]

That pully is pretty wide and the bolt used might shear off if only held at one end.  How about something like this?

A U shaped bracket that the pulley fits inside so there is support on both ends of the pulley.  This is welded to a piece of smaller square tube that fits inside the larger square tube.  The small tube open end is capped with a thick piece of metal for a bolt to push on.  It slides inside the larger square tube that has a plate with a nut welded to it on the end.  A bolt is threaded up from the bottom to push on the smaller tube bottom, extending the tube to take up tension on the belts.  Don't forget a lock nut on the tensioning bolt. 

The only problem left is a locking method at the top.  You could slot the smaller tube, put a boss on the frame and thread a hole in that.  Then you pass a bolt w/ washers through the tube and into the frame to lock it in place.  The boss should be such that it takes up the space between the frame and the tube to hold alignment perpendicular to the belts.

[Ljohnsaw]

I picked up one of these at a clearance store for $6, or maybe it was $2.


 
It didn't go well for me.  I welded in the mounting plate and it wasn't in line very well.  The belt kept running off the side.  So I pulled it.  I have another undamaged one (see my thread on  how I messed it up) if you would like it.  Just pay postage.  It has a coil spring (like a clock spring) inside the housing.

[Cornerstone]

That pully is pretty wide and the bolt used might shear off if only held at one end.  How about something like this?

A U shaped bracket that the pulley fits inside so there is support on both ends of the pulley.  This is welded to a piece of smaller square tube that fits inside the larger square tube.  The small tube open end is capped with a thick piece of metal for a bolt to push on.  It slides inside the larger square tube that has a plate with a nut welded to it on the end.  A bolt is threaded up from the bottom to push on the smaller tube bottom, extending the tube to take up tension on the belts.  Don't forget a lock nut on the tensioning bolt.

The only problem left is a locking method at the top.  You could slot the smaller tube, put a boss on the frame and thread a hole in that.  Then you pass a bolt w/ washers through the tube and into the frame to lock it in place.  The boss should be such that it takes up the space between the frame and the tube to hold alignment perpendicular to the belts.

The idler pulley bearing uses a bolt that is only 3/8 so you are probably right. My initial thought was to support it from both sides, but I couldn't envision how to make it pivot... that's when I asked for help. I can understand the second paragraph but I can't visualize your second paragraph. It seems to me the u shaped bracket holding the pulley, being pushed by a tube within a tube would be enough. Why does it need a locking method at the top?

[Cornerstone]

I have another undamaged one (see my thread on  how I messed it up) if you would like it.  Just pay postage. 

Thanks for the offer John. 

[JoshNZ]

I thought I posted a photo but I must've got distracted before hitting send!



 

I didn't ever detail it but you can see it in the photo below the alternator there.

Mines only an M10 thread, close to 3/8, it holds fine though it should be bigger. Make it an M16. The nut pulls the shafts shoulder into the slot/flat face of that bracket so it's not as though the 10mm shaft is holding the force, it just keeps the shoulder against the slot/face and that provides support for the tension.

It's not ideal to turn the belt back on itself the other way, better to push it out from the inside of the circuit but that was difficult for me, and I also needed to clear the engine mount frame 

[rusticretreater]

There is free play between the two tubes and it is certain that the physics of the situation will make the support move around.  You have seen drive belts banjo about as they are running. All of that movement is sure to continually pound on the adjusting bolt at the bottom of the part and make the tensioner bottom wear funny, move around and get out of adjustment.

Looking at any machinery and automobile mountings in particular, you will note that all tension holding devices either have a powerful spring or are mounted securely in two locations.  Either way, they are not allowed to vibrate.

[Cornerstone]

You guys are great. Thanks for taking the time to educate a brother. I really appreciate the level of detail all of you provide. 

[rusticretreater]

You're welcome.  It's a welcome design exercise for me.  You might want to divot the bottom of the smaller tube to give a positive seating for the adjustment bolt.  This would make it handle more stress I think.  

If you really want to build it right, further down cut an opening on the back of the outer tube for another frame mounted boss to fit in the opening.  This will provide a bottom alignment for the inner tube and remove lateral stress on the alignment bolt.  I was thinking of another bolt here to lock it in place too.  

A through bolt like at the top would crush the inner and outer tubes together. So no go there. You could drill the outer tube, weld a nut on and use a bolt to push the inner tube against the boss.  This bolt would need a lock nut too.  Another method would be to slot the lower part of the inner tube too, then tap the frame boss as you did the other one, drill a larger hole in the outer tube and use a bolt directly fasten the inner tube to the boss.  I think that would be a better design as it insures alignment of the inner tube at both ends.  

[Ljohnsaw]

Take a look at the WM way - they mount the engine on a hinged plate.  You tip the engine to tighten the belt.  Tip back and its loose.  With the right leverage, pretty easy to do.  The problem with idle wheels is they have to be perfectly aligned or the belt will track off to the edge.

[KenMac]

The #1 reason for only having one side adjustable is the location of the backstops. There is no reason to adjust the other side because the cant will always be against the backstops.

With one possible exception......RRQS. I found that out the other day, but there was no ill effects that I could discern.

Care to elaborate? Are you speaking of reverse roll quarter sawing? I don't know what that is.

Yes, I'm referring to reverse roll quartersawing. On my Cook's mill, when I rrqs, it is clamped anywhere from pretty much far left to 1/4 of the way to the right. My mill normally clamps against the squaring arms on the right side. I did not find any issue sawing this way on my mill as long as you're clamping tight enough to withstand the force of the saw blade.

[Vautour]

 
I'm in the middle of testing all my adjustment and my belt tensioner is on the menu, i added guides as the belt was jumping off because my pulley was not lined up but i did readjust it whit the 36'' pipe wrench and it looks pretty strait now,.. i added a small pulley with a little down pressure to stop the bouncing on the top part of the belt. i have a over TDC lever on operator's side to engage the tensioner. 
 

[Cornerstone]

 I have a over TDC lever on operator's side to engage the tensioner.

Thanks for adding to the discussion my friend. I'd be curious to see how that works if you can show a picture of it. 
This afternoon I made a channel to hold the pulley on both sides, and I think I've got a decent place to mount it. It doesn't hang any lower than the frame of the saw head, so I shouldn't loose any throat capacity.


 
In this pic you can see the slot I added to the bracket to be able to push the pulley and tighten the belt.


 

[Cornerstone]

The problem with idle wheels is they have to be perfectly aligned or the belt will track off to the edge.

This is very probable in my case. The idler wheels that I welded together were stamped steel. I noticed the surface that the belt rides on is not perpendicular to the bearing, in other words the belt surface wasn't quite stamped at a 90 degree angle to the bolt the pulley rides on. In turn when the 2 were welded together there is now a convex surface (not noticeable in the picture above) the belts will ride on. I'm guessing they won't want to ride square on the pulley, but walk apart and possibly even come off. Tomorrow I intend to add slotted holes to the engine mounting plate to take some more slack out of the belts also.

[rusticretreater]

If it ends up not working there is another thing you can do.  Surplus center sells v-groove pulleys.  Instead of pushing on the back of the belts, you can push on the v-side and be sure of controlling belt movement.

You can get a 3" double groove pulley with any size bore you want for around $18.  Of course you would have to wait for them to ship it to you.  :-\

There are also flat belt idler pulleys that are used on lawn mower decks to route drive belts.  They have raised edges to keep the belt on the pulley. They might be wide enough to support two belts.

https://www.surpluscenter.com/Pulleys-V-Belts/Finished-Bore-Pulleys/

[JoshNZ]

You might find the convex idler causes the belts to ride up on the crown, same as a band wheel does. See how you go. Mine was a square idler for a long time but it did fail one day, I put it back on the lathe and turned the guts of it down ~1/16" so it had little shoulders and it's never come off since.

[Ljohnsaw]

I got a set of annular cutters I use in my mill. after using one to cut a 1" hole I said I would never got back to using drill bits again. they are amazing just the cutter.

Do you have a mag drill or are you using a regular drill press?  I need to punch a number of 1" holes in 1.25" to 1.5" stock.  I don't have a mag drill :(

[Cornerstone]

You might find the convex idler causes the belts to ride up on the crown, same as a band wheel does. See how you go. Mine was a square idler for a long time but it did fail one day, I put it back on the lathe and turned the guts of it down ~1/16" so it had little shoulders and it's never come off since.

They have raised edges to keep the belt on the pulley. 

I'm seeing a pattern here, lol if I can't get it to run true, That'd be my next step.

[Cornerstone]

Do you have a mag drill or are you using a regular drill press?  I need to punch a number of 1" holes in 1.25" to 1.5" stock.  I don't have a mag drill :(

I DO! It's a no name cheapie but it works and is a huge advantage. I made up a gallon batch of cutting fluid by mixing a few ounces of oil with a few ounces of dishwashing detergent in a gallon of water and it'll do magic, I just squirt it every few seconds to help keep everything cool. If the surface isn't thick enough it's best to clamp everything down so the bit won't walk on you, but as long as the material is over 1/4" it stays rock solid while cutting. I've seen them as cheap as $219.

BRM-35 Magnetic Drill Press 12-35mm Boring Tapping 2250 LBS Magnet Force 980W | eBay

[Crusarius]

I got a set of annular cutters I use in my mill. after using one to cut a 1" hole I said I would never got back to using drill bits again. they are amazing just the cutter.

Do you have a mag drill or are you using a regular drill press?  I need to punch a number of 1" holes in 1.25" to 1.5" stock.  I don't have a mag drill :(

I put them in a 3/4" collet and used my vertical mill. Worked like a charm except for not having the ingot extractor. The ingots came out pretty easily with some tapping on the outside of it.

[Ljohnsaw]

I've seen them as cheap as $219. BRM-35 Magnetic Drill Press 12-35mm Boring Tapping 2250 LBS Magnet Force 980W | eBay

It looks like this comes with one metric bit (size?) and they don't look like standard bits.  Did you just use the one that came with it or did you buy some additional one?

[Cornerstone]

It looks like this comes with one metric bit (size?) and they don't look like standard bits.  Did you just use the one that came with it or did you buy some additional one?

That was just the first cheapie I found on Ebay.  The one I have is 1300 watts and came with a bunch of metric cutters. I still can't believe I only gave 75$ for it. ;D 8)

[Cornerstone]

I had some good fortune on the belt tensioner today. First I cut down the sidewall on the bracket so it'd be easier to load the pulley, spacers and washers, then picked a spot and tacked it to the frame. It's very easy to adjust the tension and the belts track straight and true.