New acquisition!

Culprit · Post by **Culprit** » Sun Apr 28, 2013 5:47 pm

I made my gasket last year from a roll of cork I had on hand. Now you've got me trying to remember if I cut the fifth hole or not. Hmmm... I know I didn't cut out the inside of the perimeter.

Well, I'm not opening it up now to check. I use it infrequently enough and for short enough durations that it hasn't been a problem. But if I come across a project where I'll need it for harder use, I'll open it up to check the oil level anyway and will check then.

I really like prmindartmouth's clear window modification, but didn't want to change the look at the time I restored the jigsaw. But the usefulness is just too good - especially since I use it so infrequently and the chances of powering it up "just for a quick cut" after it has leaked dry without knowing is pretty high.

Incidentally, I use my jigsaw for cutting shapes out of the thick triple wall cardboard. My wife uses them for dress forms for Victorian Barbie doll dresses that she crotchets.

pieceseeker · Post by **pieceseeker** » Mon May 20, 2013 8:36 pm

Well, I'm going to use the original cover myself. Going to use a thin paper gasket material along with permatex.

Checking oil level shouldn't be that hard to do. Besides, if it sits for an extended period of time, it should be obvious if any oil leaks out by any residue left over.

Reground the sealing surfaces true....

[ATTACH]21436[/ATTACH]

and waiting on 2 new seals and a bearing. Had to measure the shafts and the seal bore and depth. One seal is on backorder, so won't see those items for several weeks yet.

Holding the housing and cover together up to the light, I can just barely see a very dim line of light at the mating surfaces. Far better than when I started.

Also plan on using low strength thread lock to ensure no leaking from screws coming loose.

pieceseeker · Post by **pieceseeker** » Sat May 25, 2013 8:46 pm

Recieved 1 seal and 1 bearing so far. Still waiting on input shaft seal. In the meantime, cut out the cover gasket.

The old gasket wasn't near as bad as it looked in the beginning. What appeared to be gasket material splitting, was just a crusty layer of old crystalized oil. Scraped it off carefully with a sharp chisel. The resulting cleaned old gasket made for a nice pattern to trace.

[ATTACH]21575[/ATTACH]

Using 1/64 thick Felpro gasket material. Cutout for breather hole is same as original. Even though material is much thinner than cork and won't compress like cork, it should still provide clearance at the breather hole. Going to use Permatex sparingly on both sides of gasket for a positive seal.

Have so much experience with cork gaskets not allowing the screws or bolts on engine valve covers to remain tight over long periods of time. They always work loose and begin to seep oil.

[ATTACH]21576[/ATTACH]

[ATTACH]21577[/ATTACH]

[ATTACH]21578[/ATTACH]

Crankcase all cleaned up, ready for seal installation.

billmayo · Post by **billmayo** » Sat May 25, 2013 11:50 pm

I wish I could make that nice looking gasket, looks just like the new factory gasket I use as a copy. Mine are always a little rougher looking. I find the very small breather hole going to the outside of the housing is always stopped up with dirt and crud. I drilled the hole a little bigger on the couple of jig saws that I had been using over the years. Note: This is only a Bill Mayo Mod, not recommended by Shopsmith. However it seems to work and gasket did not leak during the time I was checking it.

pieceseeker · Post by **pieceseeker** » Sun May 26, 2013 10:05 am

Just took my time on the gasket, used new box cutter blade and paper punch on the holes.

As far as the air bleed hole getting plugged, just planning on adding this step to a "ShopSmith" check list before and after each use of the jigsaw. The passage to the cover should have enough volume to hold a lot of crud before needing to be cleaned out.

[ATTACH]21581[/ATTACH]

pieceseeker · Post by **pieceseeker** » Sat Jun 01, 2013 9:12 pm

Finished the rebuild on the jigsaw crankcase tonight. Test ran it for about 30 minutes.

No leaks, no runs, no errors. It's looking good. Lower chuck and shaft were slightly warm to the touch after the test run. Housing was still cool.

Lower chuck shaft seal had a small glistening of oil at the outer lip, which I would consider good. It needs lubrication too!

[attach]21708[/attach]

Only problem I'm seeing is the pulley won't set straight on the shaft, about a 1/4" wobble. It's a strange looking bushed pulley to say the least.
[attach]21709[/attach]

[attach]21710[/attach]

[attach]21711[/attach]

Long story short, Congress Drives is still in business, I have a fixed bore pulley coming from Amazon for $17 for 4L belts which is what is on there now. SS# 513854-03 4L400

On a side note, I used 10w turbine oil from Ace Hardware. It's supposed to be a highly refined non-detergent lubricant. It is very clear oil and comes in a 4oz bottle with a 8" very small spout.

Looks like it would be very handy for oiling sheaves and shafts in the headstock.

On another note, while doing the test run, I could feel a constant flow of air coming out of the breather hole in the side of the crankcase. I was quite surprised to feel that much air.

billmayo · Post by **billmayo** » Sun Jun 02, 2013 12:41 am

[quote="pieceseekerOn another note, while doing the test run, I could feel a constant flow of air coming out of the breather hole in the side of the crankcase. I was quite surprised to feel that much air.[/QUOTE"]

Thats why if the breather hole get stopped up from crud, dirt or paint, the gasket will always leak. Most of the jig saws I have handled has the breather hole stopped up and the gasket is sipping oil.

pieceseeker · Post by **pieceseeker** » Sun Jun 02, 2013 7:07 am

Very similar to the PCV system on an engine. An engine that is leaking oil may only be a plugged up crankcase ventilation problem. That system prevents a positive pressure buildup in the crankcase, which will force oil out the path of least resistance.

JPG · Post by **JPG** » Sun Jun 02, 2013 7:56 am

Hmmmm! Since there is nothing in the crankcase that is changing 'volume', what pray tell is acting as an air pump?

I believe the purpose of the 'breather' hole is to tolerate atmospheric pressure variation.

Gotta admit I have never 'checked' for air flow when operating!

pieceseeker · Post by **pieceseeker** » Sun Jun 02, 2013 8:39 am

Well, I believe it would have to be the crank throw and/or the yoke bracket creating the air movement into and out of the hole. And then there's the lower chuck shaft moving up and down in a blind hole. Even though the shaft is hollow, I would think there's gotta be some kind of pumping and sucking action there.

Air movement has inertia, so a momentary pressure buildup..say the chuck shaft moving down into the lower hole forcing air out of the upper hole where the cotter pin is, would create a positive pressure in the crankcase. That is where there would be actual volume change.

When I was first putting the shaft and yoke together, I filled the blind hole in the bottom of the crankcase with oil, put the shaft into the hole. I then turned the pulley several times by hand and noticed oil coming out of the upper hole with the cotter pin in place.

And what is the real purpose of that cotter pin above the yoke bracket?

I'm planning to use my manometer from work to verify the actual movement of air flow. My gage is digital, the airflow in and out may be quicker that the screen update is able to handle. It has no min/max capabilities, so we'll see.