LumberJocks

Ridgid 4512 saw 4-wheel mobile base issue

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by Mike335 posted 07-23-2019 12:26 AM 240 views 0 times favorited 8 replies Add to Favorites Watch
View Mike335's profile

Mike335

5 posts in 28 days


07-23-2019 12:26 AM

Hey guys, I bought a used Ridgid R4512 table saw that’s equipped with the four-caster mobile base. I dismounted and disassembled the mobile base to clean off some rust, and after I reassembled the base, the casters will not remain locked down in the rolling position. The slightest bump causes the saw base to retract unless I keep my foot on the pedal that lifts the saw into the rolling position. This is very awkward and inconvenient. This topic came up on the forum previously in a post by user SawdustyDan in 2015, but after he apparently received a replacement set of casters, he posted no follow up to say how they worked:

https://www.lumberjocks.com/topics/90498

I believe I’ve reassembled the base correctly as per the manual. I tried reversing the shaft or axle that joins the aft pair of casters end-to-end, but that didn’t improve things.

Anyway if anyone owns the four-caster version of the saw, I’d like to hear any guidance you can offer. Thanks in advance…


8 replies so far

View Delete's profile

Delete

439 posts in 822 days


#1 posted 07-23-2019 01:43 AM

These mechanisms normally lock in place when a eccentric is rotated over center. If the eccentric does not go over center it will not lock and will slip back. How is the pedal fixed to the shaft is it tack welded or is there a bolt or set screw locking the pedal to the shaft. If it is bolted, it is possible it has slipped on the shaft and when you depress the pedal it no longer rotates the eccentrics over center to lock it in place. If this is the case you should be able to loosen the bolt or set screw reset the pedal to its proper location and retighten the bolt or set screw. Check both shaft mounts, if one slipped the other may have as well. Without a more detailed diagram, I am just guessing here, but it is worth a look.

View Mike335's profile

Mike335

5 posts in 28 days


#2 posted 07-23-2019 04:19 AM

Thanks for your response Carlos. The pedal on the front axle and the lever on the rear axle that are connected by the “center support” appear to be fixed with set pins, not screws or bolts. They seem quite firmly attached to the axles. I suppose they may have slipped a few degrees from use, but I don’t think so. I’ve rigged a kind of lock using a turnbuckle attached to a longer substitute set bolt on the pedal which I can in turn hook to an eyebolt I’ve mounted to the front of the stand. This complicates the lock and release process, but now I can at least move the saw without the casters retracting prematurely.

View Delete's profile

Delete

439 posts in 822 days


#3 posted 07-23-2019 05:11 AM

Yes that increases the work, but it works. Did it ever lock since you had it. If you want to have a close look at the ends of the shafts where the eccentrics would be, it could be something has come loose there, if the pedal didn’t slip something like the eccentrics could have. There has to be a reason why they are not rotating far enough to lock. If Ridgid used really cheap metal like zamuk they could have wore out, but I doubt that, something could be bent, disassembly should find that.

View Mike335's profile

Mike335

5 posts in 28 days


#4 posted 07-23-2019 06:00 AM

The base did seem to work properly before I took it apart to clean off the rust. I believe that the “cams” in the caster assemblies are rotating as far as they need to, but for some reason they aren’t locking with sufficient authority. I disassembled the entire base for cleaning/coating, and detected nothing that stood out as “wrong,” or damaged. I photographed the assemblies before I took them apart, and believe that I put them back together correctly. I coated the parts in a beeswax mixture I use to prevent rust—I wondered if this and cleaning the rust off may have made the contacts where the cam-like triangular parts rest on the plated caster mount too slippery, so I cleaned the wax off the places that I thought could now be too slippery with thinner to remove the wax. This didn’t fix the problem. You can see the triangular cams in the photo I took before cleaning and coating the surfaces. These are bent into a squared “U” shape during manufacture. The ends of the axles are ground with flat sides and the cams have the same flat-sided holes to receive the shaft—they cannot rotate on the shaft, and are very positively locked in position relative to the axle so that the torque will not shift their position on the axle shaft when the axle rotates to raise and lower the casters. So I’m pretty much stumped, and resorted to the turnbuckle solution.

View Delete's profile

Delete

439 posts in 822 days


#5 posted 07-23-2019 06:58 AM

Those pictures clarify it for me. They are both where the locked position should be, and I can’t see how they could slip from that position with the weight of the saw on them without lifting the pedal to assist the rotation past the high point on the eccentric. They should lock in that position so for the life of me I can’t see why they are not.

You could check to insure they are in that position with the pedal depressed and you should have the saw well off the floor. Maybe check to see if you can mount them a little lower on the legs to give you more floor clearance when you are moving it. Without good weight on the casters all the time when it is raised the eccentrics won’t stay locked.

Edit: Looking at the wear on the high point of the eccentric, it is possible the flat locking surface after the high point has been rounded making it easier to release. A file to flatten the locking surface so it mattes closer with the caster might help. If they are used alot the transition from the high point to the locking surface will tend to round out through normal wear.

View Mike335's profile

Mike335

5 posts in 28 days


#6 posted 07-23-2019 09:20 AM

Two things: the saw was kept on a gravel surface by the original owner, and the casters were virtually unused (always retracted) until I bought it. The rust is superficial, and the cams and the surfaces where they bear and chafe aren’t worn to any noticeable degree. Second, when the saw is in the raised position (feet about 1/2” clear of the floor) there is probably over 200# of weight on them—the manual forbids raising the saw solo after the inverted assembly. When I attempted to violate this stipulation after cleaning up the base, I immediately realized that I was well out of my depth. This thing is heavy.

View Delete's profile

Delete

439 posts in 822 days


#7 posted 07-23-2019 09:46 AM

Well you got me then, maybe someone else has figured that one out and sees this.

View Mike335's profile

Mike335

5 posts in 28 days


#8 posted 07-25-2019 11:52 PM

In case anyone finds this post and decides to do this hack to their R4512 mobile base, I thought I ought to post a refinement of the rig that I found necessary. Two things were interfering with the original turnbuckle fix: The turnbuckle as I originally attached it to the pedal could not apply sufficient tension/torque, so I added a piece of aluminum scrap that I had handy to extend the turnbuckle connection in order to increase leverage (and torque) on the pedal and axle. The second problem was that the turnbuckle’s tension on the eyebolt was bending the metal of the base and the eyebolt was deflecting too much under tension. To resolve this issue I added a scrap rectangle of .25” ply and a 6” long .75”X.125” steel strap under the back of the eyebolt to stiffen the saw base where the turnbuckle is mounted. These two modifications keep the casters rolling and the saw base feet clear of the floor with more authority. I used materials that I had at hand, and plan to refine this rig a bit more with appropriately sized bolts, bushings, and washers next time I can get some in town.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com