blade height adjustment seized ?

[tribalwind]

Hey guys,

having a "duh" moment and cant find teh info on rectifying this problem.

my bt3's blade is VERY difficult/impossible to adjust.
i'm assuming i need to squirt some wd-40 or lithium grease in there somwhere/how but want to get the right info. maybe some bolt is jsut loose or froze or somethings gotten misaligned ?

any help on this would really be appreciated, and apologies in advance for not having the wherewithall today to find this myself (usually good at that!)

[LCHIEN]

the frequent causes of this are listed I think in the BT3 FAQ - link below by sig line.

[tribalwind]

thanks loring i'll check that
i had better search results after posting.
fund some good info now to get me started!
it's probably sawdust buildup in the mechanism,i'll blow/clean out tonight

[rfalkiner]

Alternate fix no helicoil

I had same problem which turned out to be excessive wear in the jackscrew assembly, eventually resulting in stripped threads.

I replaced the jackscrew with a 3/8" x 10" carriage bolt (left over from a deck project) and epoxy/pinned a 3/8" extension NUT in the hole in the motor casting, so now I have a steel/steel jackscrew assembly instead of a steel / aluminum casting, which will wear.

I drilled the carriage bolt across the diameter same as the original jackscrew, and used the factory gear and roll pin to mate the parts. Grind the head of the carriage bolt to fit. I ground the hex flats of the extension nut down until it friction fit into the stripped aluminum casting jackscrew female thread hole. Epoxy cured overnight (used JB Weld metal filled epoxy, but any will do) and mechanism is silky smooth again.

Bonus is that this bolt is 16 threads per inch, so one turn of the wheel now raises or lowers the blade by 1/16" instead of the original 1/12 inch which was aggravating. Who does woodworking in 1/12's of an inch?????

Note - An extension nut is about 1 3/4" long and is normally used to butt join two lengths of threaded rod together.

[Ed62]

It could be as simple as giving it a good cleaning. Take the side panels off to get a good look at it. An accumulation of sawdust can make raising and lowering problems.

Ed

[Sugaray]

I just helicoiled the height adjustment on my BT3000 and wouldn't you

guess, it didn't align with the hole at the bottom, so---many thanks for

the 3/8" carriage bolt solution. I'll give it a try.

Sugaray in WVa

[rfalkiner]

Details on 3/8" 16 TPI carriage bolt fix for blade elevation

Another member asked me for more details on how to use the carriage bolt fix and this is the response I sent (forgot my password or would have posted it earlier). I sent a picture of the finished assembly. Is there a way to upload pictures to this forum (I don't have a web page set up).

BTW - I think I used an 8" carriage bolt not a 10". I bought 2 as was unsure which would fit better, and the 10" one is the unused one. The 8" carriage bolt allows full up/down travel without any cutting.
============================

The gear is attached to the jackscrew with a simple roll pin. drive it out using about a 1/8" dia pin (can use a drill using a piece of wood for the hammer if you don't have a set of drive pins)

The square flats on the shaft just under the head of the carriage bolt have to be filed or ground to fit into the lower casting flange and gear. Try and make this smooth as it becomes the bearing surface to keep the shaft on centre. Once in, mark throuh the roll pin hole in the gear where a hole has to be drilled through the diameter of the bolt to pin the carriage bolt to the gear. start with a small drill and work your way up. Carriage bolts are pretty soft, and are easily drilled using a little bit of oil for lubrication.

The gear and the head of the carriage bolt keep the bolt pinned in the bolt in place. The weight bearing surface does not change (gear, lower casting flange), so should get many years service.

Attached is a picture of the completed assembly taken from the bottom of the saw looking upward. I think made a mistake in the note in that I used a 8" carriage bolt not 10"

I was going to epoxy a couple of small glue brushes on to clean the threads on way up/down but this has proved to be unecessary. I was pleasantly surprised how silky smooth the action is, and how accurate it is (I checked some cuts with a depth gauge). Since each full turn of the wheel is now 1/16 of an inch, a 1/4 turn is 1/64" or about 15 thousands of an inch. It is relatively easy to set the depth to within less than 1/8 of a turn of the wheel which gives less than 0.005" accuracy, and a good friction fit. Just by setting "zero" by running a piece of wood over the retracted blade while raising the blade until it scratches the wood and the blade turns. Then just cound # rotations to set blade depth, with the bonus that you can use your decimal / drill chart to get equivalents, because everything is now based on 1/16 of an inch.

After I did this I can't understand why all saws are not made with either 1/10" or 1/16" height per wheel rotation. Why would Ryobi and many others pick 1/12" in the first place???? Not many woodworkers think in dodecimal units (12) when everything they use are either decimal (10) or hexadecimal (16)

[cgallery]

Another member asked me for more details on how to use the carriage bolt fix and this is the response I sent (forgot my password or would have posted it earlier). I sent a picture of the finished assembly. Is there a way to upload pictures to this forum (I don't have a web page set up).

When posting, look for the button down at the bottom that says "Manage Attachments." This will allow you to send photos from your machine directly to bt3central. I think the only requirement is that they be less than 97.7K (so you may have to resize them).

Can't wait to see the pictures!

[rfalkiner]

picture 3/8" carriage bolt fix

Thanks for the assistance.

This is picture of finished assembly taken from bottom upward. It was about a 2-3 hour job in two sessions because you have to take apart so much of the saw and re-assemble. Only took me 10 tries to get it down to the size limit, but now that I know how to do it, its simple.

As always, experience is what you get immediately after when you really needed it.

[cgallery]

So when using the carraige bolt do you have to drill-out and re-thread the bracket that holes the blade/motor? Or did you use a helicoil or ?

Thanks, looks good, interested in hearing more. Mine is working fine but this seems to be a common failure mode for these saws so I'm interested in hearing good solutions.