Author Topic: Another build thread... JoshNZ (Read 20517 times)

JoshNZ · « **Reply #460 on:** September 21, 2020, 03:32:54 PM »

I don't know what size the battery is but I'll assume it's at least 60Ah generously, at .2mA drain it'll take approx 34 years to empty it if I've done the math right so I'm ok with that. I just wondered if it's normal to have any draw with the voltage regulator off and if not, is it a sign of pending failure.

JoshNZ · « **Reply #461 on:** October 04, 2020, 03:47:42 AM »

Had the first big blowout today with a main bearing on the idle wheel failing. Let go with a bang, blade flew off etc.

I can't find any info about the rating of this bearing here. It's got written on it FAG UC208-24 and M1216-08.

Is a 1.5" bearing enough, can I find a high load one or do I need to go up in shaft size? Or turn collars for my current shaft and go up in bearing size? They were quite a tight fit, it may be that I damaged them while pressing.

charles mann · « **Reply #462 on:** October 04, 2020, 08:16:05 PM »

@JoshNZ
Does you idle wheel have enough meat around the bore to machine it out, leaving a lip and get a set or a single bearing/s, drill/tap the front face and press in the bearing/s and install a cover plate, bolted to in the tapped holes? An example,
https://cookssaw.com/25-metal-band-wheels/

Replacing the tapper bushing with bearing/s
https://cookssaw.com/bearing-for-idle-band-wheel/

Then turn a shaft that fits the ID of the bearings, weld on 2 pcs of 3/8” (whatever metric) 2x3-4” angle, slotted to match up to your existing pillow block holes and bolt it on.
Something similar to this for the idle shaft,
https://cookssaw.com/standard-idle-shaft/

Crusarius · « **Reply #463 on:** October 04, 2020, 09:49:32 PM »

my bearings were a super tight fit but with persistence I was able to slip the shaft into it. I do not believe that should be a press fit into those bearings. I do wonder if that is whats causing a failure. There is actually someone on my forum that just had the same type of failure with 1.5" bearings.

I have 1-7/16" shaft and have had no issues at all. One day I will try the caliper trick to find out how much blade stretch I have.

JoshNZ · « **Reply #464 on:** October 05, 2020, 05:06:28 AM »

I ended up just replacing the bearings, will see how it goes one more round. I did put the shaft back in the lathe and polished the journals down until I could tap fit the bearings. Excessive interference and the blasting from a hammer/drift can't have been good.

KenMac · « **Reply #465 on:** October 05, 2020, 09:01:57 PM »

All pillow block bearings I have ever seen were slip fit not pressed or tapped on. I've replaced probably hundreds over the last 25 years as a commercial HVAC mechanic. For what it's worth.

JoshNZ · « **Reply #466 on:** October 06, 2020, 01:48:46 AM »

Thanks Ken. It's tap fit now, rubber mallet tap.

JoshNZ · « **Reply #467 on:** October 06, 2020, 02:38:14 AM »

This is the stack of logs that ended up arriving. Some crap walnut, some decent walnut, and most of the blackwood looks in pretty good shape.

I pulled the longest walnut log off the pile when it was small and sawed two 16ft 12x4" beams out of it. Lots of movement when sawing unfortunately, but it was a smaller log. The cracks in the log ends want to continue opening if sawing perpendicular to them (i.e. blade spanning the crack) which will be a real problem for the logs with stars in them, will be lots of sawing curves and bellies out of cants and lots of firewood logs there I suppose.

I put the beams up on posts and used some old galv ag beam we use in the orchards here to span them. Will put some tin on it tomorrow. Piles are driven in behind the tractor for the mill to go on. All temporary, I don't know how big the beam should be but I did try bouncing in the middle of it and it doesn't move, so I hope it'll do a few months.

thecfarm · « **Reply #468 on:** October 06, 2020, 06:50:12 AM »

Like the dog in the picture. My dog would fellow me whatever I went.

Hilltop366 · « **Reply #469 on:** October 06, 2020, 08:46:18 AM »

Wondering... if both bearings were locked to the shaft as they warm up with use would they transfer enough heat to the shaft to cause the shaft to lengthen slightly creating a thrust (pushing) on the bearing?

JoshNZ · « **Reply #470 on:** October 06, 2020, 02:24:37 PM »

I think it'd be negligible, they don't heat enough. I had a similar thought though of whether or not I should lock the shaft to the bearing before adjusting the tracking. Since your bearing point technically draws an arc around your other point, but your pillow adjusts in a line. I think it's negligible also.

Yeah the dog is good to have around she's never far from me.

Hilltop366 · « **Reply #471 on:** October 06, 2020, 04:11:43 PM »

What got me thinking of that was the trailer hub and spindle I had on my CSM would get warm enough that I had to run a little extra slack in it when cold to prevent it from binding when it got warm which would make it warmer and get worse.

Could keep an eye on the bearing temp and try it with the inner one unlocked if it felt warm for comparison.

JoshNZ · « **Reply #472 on:** October 08, 2020, 04:47:50 AM »

I got my little mill shack finished today. Looking forward to spending some time under it...

I pulled another log off the stack, 2 down, ~70 odd to go. I didn't have my log hook so I picked the smallest one I could reach, which had a bunch of stress in it too.

From the two logs I've played with I think I've figured out it's the sapwood in tension that is pulling the ends open and causing issues. I'm hoping if I cut the sapwood off before taking cants and boards I'll be ok with the heart. Will be pretty low recovery but it is what it is.

I took a couple of slabbing cuts just to watch what the log did and they all just about explode open along their pith. I turned them on their edge and ran the saw down the split, then sawed again to get straight boards from them, cross cutting in half if necessary. So I've ended up with straight boards but whether or not they're going to stay like that...

If anyone has any thoughts on dealing with logs with cracks in their ends that want to continue splitting, feel free..!

Thought I might get away with just edging this one that didn't have a split but no such luck. Exploded apart about 2ft into the cut

Magicman · « **Reply #473 on:** October 08, 2020, 08:27:53 AM »

Turn the log so that you are sawing parallel to the pith check/crack.

JoshNZ · « **Reply #474 on:** October 08, 2020, 03:50:27 PM »

This one was a 3 armed star from memory. Some of them are 4 which makes things tricky right?

If I've taken a board that has crooked and I then remove sapwood and edge it on the mill and see no further movement, is it likely to warp while drying? There's not much more for it I can do at that point is there

JoshNZ · « **Reply #475 on:** October 08, 2020, 05:23:10 PM »

@YellowHammer I was playing around with feeds in this log too, getting a little bit of mixed results. I remembered your post on my blade thread a while back and tried a cut pushing to the point where the engine just barely started to bog, which felt wrecklessly fast to me. But it was by far the best surface finish I got all afternoon.

I did notice however there was a knot in the end of the log and I was getting a faint wave as I hit this, with the high feed speeds. Should I be lowering rake if I see this, or slowing feed down for knots or is it just unavoidable?

YellowHammer · « **Reply #476 on:** October 08, 2020, 10:17:25 PM »

Nice on the cut speed, before long you'll get used to sawing fast and getting the maximum power out of your mill while getting a good clean cut. There is a bit of driving involved, like a car slowing down for the turns, then accelerating out of them. Same thing with knots, if it's a little one, just power on through, if it's a big knot, take your foot off the gas, get through, and them power back up.

It's critical to watch the rooster tail of the sawdust coming out of the kerf, as it's the best way to tell real time what's happening in the cut. If the rooster tail jerks, twitches, or angles upon or down like the needle on a gauge, then that indicates that the band is waving up or down. If the rooster tail settles in line with the band then the band is cutting straight. If the sawdust looks like a spray but is inline with the band, then that is what actual gullet spillage looks like. If the sawdust is in line with the band but spraying, then the band is cutting straight, but is getting dull, or is overset, because the sawdust isn't staying trapped in the gullet of the band.

The absolute best look when the band exits the cut and there is no gullet spillage. This is when you almost can't see the sawdust, and it looks like the band is simply cutting through the log like a knife. This is the epidimy of sawing fast and straight, and when you see it, you won't forget it. You'll also feel it with the way the engine sounds and feels, and the way there will be almost no sawdust on the board after the cut because its all being ejected.

The cool thing about watching the sawdust roostertail is that you'll know the condition of the band, at all times, as you saw. You can actually see it starting to dull, and you'll know when you are starting to lose a straight cut, with instant feedback so you can make an immediate correction, and not after you stack the board sometime later.

JSHogue · « **Reply #477 on:** October 09, 2020, 06:15:48 AM »

Quote from: JoshNZ on October 04, 2020, 03:47:42 AM

Had the first big blowout today with a main bearing on the idle wheel failing. Let go with a bang, blade flew off etc.

I can't find any info about the rating of this bearing here. It's got written on it FAG UC208-24 and M1216-08.

Is a 1.5" bearing enough, can I find a high load one or do I need to go up in shaft size? Or turn collars for my current shaft and go up in bearing size? They were quite a tight fit, it may be that I damaged them while pressing.

(Image hidden from quote, click to view.)

How many board feet or hours do you think you’ve sawn before this bearing failed? Did it give you much warning? How do the others feel?

JoshNZ · « **Reply #478 on:** October 10, 2020, 05:14:26 AM »

It did give plenty of warning and I ignored all of it, in hindsight. I remember quite a while ago I started getting a rumble and the blade guard door was vibrating, I just thought it was a new harmonic. A few sessions later I ran it up in the shed and it didn't quite sound right, and lots of vibration in the blade. Ive finished looking for teething problems and now was just too keen to get sawing to pay it any attention. Need to get into a habit of pre-checks and general maintenance observance now.

The others are fine, I replaced both on the failed side after polishing the shaft down to a tap fit. I remember the bearings being really hard to get on I think I probably damaged them during installation, and overdid the interference fit.

YH I've definitely noticed the rooster tail change consistency with a dull blade, not sure I've noticed it twitch or jerk or move, I'll keep and eye on it and see if I can make some sense of it.

Crusarius · « **Reply #479 on:** October 10, 2020, 09:54:20 AM »

Thanks for that info yellowhammer, My mill should be back together and running by sunday. I will pay attention to that.

Forestry ForumSponsored by:

Author Topic: Another build thread... JoshNZ (Read 20517 times)

Forestry Forum
Sponsored by: