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By Sideways
#1205588
C Sideways 2018

For anyone in the same position as myself, deciding whether to buy a used Kity 613 bandsaw and then setting about a clean and tune up, I hope the attached photographs and notes may be of use.
Thanks to everyone else on the web (especially the French forums) who has shared similar and often better information over the years.

My machine is an original model 613, made in 1993 by Kity SA in France. It was bought via ebay and looks to be lightly used. The alloy table is in decent condition for it's age, as are the tyres and blade guide assembly.

I decided to strip the machine down to check on the extent of some relatively minor rust, to deal with what appeared to be motor noise and to learn how to tune it.

As a general point, I find it useful to keep a small selection of stainless machine screws, nuts and washers in the common M6,8,10 sizes. As the saw will live in a garage workshop and suffer damp through winter, I replaced various fasteners with stainless if I had them on hand to avoid corrosion.
Starting with the blade guide. Clamp knob at the back, side nut has a pinion that moves the guide up and down by the rack cut into the back side.
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The upper blade guide assembly just pulls out when the clamping screw is slackened.
The side guides are held in place with M6 nuts.
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The side guides use plain bushes of some sort, not ball bearings. They turned freely so I didn't have to dismantle them (it's not obvious how you would, but a jig to pull them apart would be my guess when the time comes).
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I am debating whether to lube these bushes - thinking about an aerosol like bike chain lube

The thrust bearing is a standard size sealed unit 6200 2RS. I ordered replacements by SKF, FAG and NSK. I like the SKF best for this application. The old bearing is worn but serviceable so stays for now. A bearing puller will be useful when it is time to replace it.

The cast alloy table was unbolted and cleaned with some light oil and a "non stick" grade of kitchen scouring pad.
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I replaced the existing M6x20mm hex countersunk machine screws with torx socket stainless. Stainless are not so strong as the originals but I think they will be strong enough. Torx sockets (I think even in stainless) are less prone to strip than the 4mm hex sockets of the originals.
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The table tilts on a trunnion of pressed steel and cast alloy. I used a more aggressive scotchbrite pad to remove rust from the machined edges of the two steel brackets.
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Note there are differently sized washers between the curved steel brackets and alloy casting. Take a note of the order of the parts when disassembling to make sure they go back in the right order.

End of part 1
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Last edited by Sideways on 03 Feb 2018, 16:10, edited 2 times in total.
By Sideways
#1205622
Part 2

The lower blade guide is a simple arrangement with two wooden rubbing blocks. It is made from alloy with knobs machined from unprotected mild steel. These needed a good clean with scotchbrite and a soak in rust converter followed by light oil.

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The bearings were still good so no need to remove the wheels.
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Next step was to remove the glaze of compacted dust and rust from the tyres. This was done by hand with fine steel wool.

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Reassemble the machine and fit a new blade. Tuff supplied a good general purpose blade in just a few days. 90 1/2" x 1/2" 6-10 tpi varitooth in M42 steel. Following the instructions, the blade tension and tracking is adjusted to run the teeth of the blade just off the edge of the flat tyres.
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Ran the saw up with guards in place minus the table to check tracking. All looks good but the motor is very noisy when running. Perfectly smooth and quiet when turned by hand. The noise suggested a problem so I removed and stripped the motor - a Leroy Somer unit from 1993 (1100W (1.5hp) input 740W (1hp) output with a 20uF 400V rated start run capacitor) wrongly guessing that there might be a centrifugal switch inside causing the the noise.
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Take note of the position and orientation of the intermediate bracket when you remove it from the motor to save having to figure it out on refit. Two corners are chamfered to clear the frame of the saw so there is only one correct way to fit.
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Removing the plastic fan was a challenge. I guessed that it would be a push fit on a splined shaft (correct) but there was nowhere to get a lever or puller into the job. In the end I just clamped the main spindle in softjaws and twisted / pulled the fan until the plastic gave and the thing came off.
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Inside of the fan
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End of part 2
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Last edited by Sideways on 03 Feb 2018, 15:19, edited 2 times in total.
By Sideways
#1205623
Part 3
Opening up the motor
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The squirrel cage (stamped 1TC131) and bearings. NSK 6204-2RS1 main and 6201DU tail. Both perfectly good so no need to replace.
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Stator and end caps. Again looking good.
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Cleaned the dust from the two ends and reassembled.

Main bearing is inserted first. Wooden block in between and tap the end of the shaft with a hammer until the change of sound tells you that the bearing has bottomed in the end casting.
Tail end casing then taps on the same way. Note the thin blued spring washer that sits between the outer end of the bearing and its seat in the end casting.

A roll of tape was enough to help me drive the tail end casting squarely into place. Take note to align the holes for the long thin bolts just as the end casting presses onto the motor main frame. You won't be able to turn it after it's tapped home.
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When the end casting is seated, the blue spring washer is just visible. Neither loose not fully compressed.
The tie bolts can then be tightened. They have an unusual head. For disassembly I wriggled them free with short and long nose pliers as they are not tightly fastened and have anti-vibration washers. A slot ended tool would be useful for re tightening them without damaging the heads.
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As the motor looked sound and there were no parts or loose laminations that looked like the source of the operating noise it was time to check the capacitor and the No Volt Release switch.

Cap is a 20uF 400V rated part. Totally generic. As there's no centrifugal switch it must be permanently connected and rated for run as well as start. The motor started ok so I have no reason to think there's anything wrong with the capacitor but they do age. I have another Kity machine made in the 90's that sat in a crate for 20 years until I bought and assembled it. The capacitor exploded in a cloud of smoke 10 seconds after starting the saw for the very first time :-)

Check and blow out the connecting box on the motor.
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Check and blow out the NVR switch. Everything clean and tidy.
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At this point I everything looked in order so I powered up the motor on the bench and everything ran smoothly with no excess noises.

I used some scotchbrite to clean a little rust off the spindle while it turned.

Check the motor body tie bolts are tight (as you can't access them properly when the fan is in place) then tap the fan back onto the splined motor shaft.
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I left the black plastic fan 2-3mm short of the original position when refitting to give more clearance between the insde of the fan and the motor body in case the slightly soft plastic of the fan was distorting at 3000 rpm and causing noises by rubbing on something (though I saw no marks from this). The fan creates a powerful draught.

End of part 3
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Last edited by Sideways on 03 Feb 2018, 15:39, edited 1 time in total.
By Sideways
#1205624
Part 4

Clean and refit the polyV drive pulley. A little grease on the shaft and the loose key first, then assemble, spin the motor and use scotchbrite to remove some corrosion that had built up on the pulley. Another sign that the machine has seen damp at some point in the past.
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Bolt the intermediate bracket back onto the end of the motor and then reinstall everything back on the saw. Guess the poly V drive belt tension as a couple of mm deflection under firm finger pressure.
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This time the saw runs without any unexpected noises. I don't really know what I did to fix it but suspect the fan was rubbing somewhere. I'm happy that i've seen pretty well all of it in detail and there are no surprises waiting for me.

To finish, i remove the cover over the blade tension and tilt mechanism so I can clean it out and apply a good spray of rust preventing wax. The cover pulls off once four small screws behind the upper band wheel are removed.
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The mechanism is basic with painted sheet metal rubbing against painted sheet metal. But there's only limited movement and nothing seems much worn. Spray and put it back together.
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Some test cuts and all is useable until the weather improves and I can tackle some rust on the motor cover. I will strip this and repaint with Flag brand green hammer finish enamel. It's a toluene based paint unlike the latest formula for Hammerite so not a job for indoors.
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Having stripped it, i'm confident that the machine comes apart quickly and easily enough for maintenance. Fine tuning is for another day but the blade tracks off the front of the flat wheels as it should, the motor is pretty quiet, and the trunnion seems robust enough for my needs.
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End :-)
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By Sideways
#1206210
Thanks Powertools :-) It's kind of you to say so and makes putting the post together worthwhile.

I'm a total newcomer to bandsaws. This is my first. I will be grateful for any good advice you or other owners out there care to offer :D

Before starting to take this machine apart I spent some time searching the web for similar blog posts to help me along. There is one particularly good one posted on a French site that seems similar to ukworkshop but I couldn't find so much in English language.

As a newcomer to the machine the main things that I learnt are:
1. the flat bandsaw tyres are a little unusual so you have to have a manual or know from elsewhere that the proper tracking is with teeth off the edge of the tyre. I don't have the manual so it was great to find it on the web.
2. it seems like you have to learn a knack of adjusting blade tension and tracking knob alternately to get the blade at a sensible tension and in the right place on the tyre. Altering tension moves the tracking and now I think about it, altering tracking must change the tension. I hadn't thought about this before.
3. at first glance the motor in this looked a little "cheap" because it has no fins or weather sealing on the outside. Very like a washing machine motor. I guess it doesn't matter because it is enclosed in it's own vented box at the back of the machine. It works well. It comes apart very easily except for the fan which just requires brute force. It looks super easy to replace the bearings as long as you have a puller, and it went back together without any drama.

I have some nostalgia for the Kity machines so I'm just happy that this old machine doesn't seem to be a lemon !
Last edited by Sideways on 13 Mar 2018, 17:17, edited 1 time in total.
By NeeKlaus
#1213356
Thanks for this - good reference pictures. The upper side-guides remove easily enough - remove the pair of nuts in image 3 and the guide housings come away. You can then unscrew them - the thumb nut to one side, the bearing and threaded shaft to the other.
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By Robbo3
#1213371
Very nice. You have obviously taken great care.
From a bought in shaft & components, I used to make (fabricate/build) brush motors. As a generalisation, if you can't see any means of fixing other than splines, then it's a two screwdriver (used as levers) job.