Replace bearings on a DeWalt DW700 saw

jack of all

I hope someone here could point me in the right direction- I went to use my old DW700 mitre saw today and found the blade was coming to a halt immediately after releasing the trigger, I hadn't used it in a while so don't actually know how long there's been a problem. Anyway I removed rear casing to the motor and after I pulled the arbor pulley off I was able to establish that one or both bearings on the saw arbor (as opposed to the motor armature) are shot. It should be an economical repair as the bearings will probably cost €20 or so but I wonder is it possible to remove the old bearings and press in new ones without a proper press? I was planning to use my mechanics vice and socket to perform this task. Has anyone done anything similar, is it do-able? I'd rather do the job myself as the saw is old and probably not worth sending out to a professional workshop for repair.

gutteruu

All bearings are designed to be replaced. If you heat up the bearing before putting it on it should go on easily. A heat gun works fine, but I like to soak them in any hot oil. A piece of metal the same diameters as inside slieve of bearing should help beat it on if in trouble.

K.Flyer

gutteruu wrote: »

All bearings are designed to be replaced. If you heat up the bearing before putting it on it should go on easily. A heat gun works fine, but I like to soak them in any hot oil. A piece of metal the same diameters as inside slieve of bearing should help beat it on if in trouble.

Do you not mean that he should heat the casing that the bearing fits into?
By heating the bearing itself you make it expand, therefore creating less space for it to fit into.
An engineer gave me a great tip when I was younger and rebuilding old British motorbike engines...
Heat the casing gently and the old bearing should drop out with a light tap.
Place the new bearings into your freezer for an hour or so before you need them. After cleaning out the casing that holds the bearing apply some gentle heat to it for some slight expansion. Apply a light dab of bearing to casing adhesive and if done right you should be almost able to push the bearing into place with your thumbs.
Casing cools down, bearing returns to normal temp and everything locks nicely into place.

jack of all

I managed to extract the old bearing with a large socket, some threaded rod, washers and nuts so once I've ordered a replacement I should be good to go.

gutteruu

K.Flyer wrote: »

Do you not mean that he should heat the casing that the bearing fits into?
By heating the bearing itself you make it expand, therefore creating less space for it to fit into.

It seems completely counter-intuitive. I used your way for years using freeze spray, but my father who sold bearings told me to try this and I haven't looked back. Apparently they don't expand like you would expect due to design. I don't understand reasoning but I change large bearings every few weeks and it works great for me. (Freeze works better on ZZ sealed bearings I find)

Flood

Dealing with such small bearing using heating/cooling techniques are unnecessary for this job.

jack of all

Job is now done and saw is working very well! In the end I did freeze the arbor to assist with fitting bearings on it, also heated aluminium pulley before re-fitting. I don't know if it made a whole lot of difference but everything went back together pretty smoothly without resort to brute force! It was a great opportunity to clean dust from the motor, clean the commutator, check brushes and clean the blade guard assembly which had been sticking for a long time and was a source of annoyance. Hopefully I'll get a few more years from it.

Pie Man

Hi.
How to I remove this ball bearing? You can see on the second picture there is a grove on the bar (there is a second grove at the far side), do I need a special tool to grab it and screw it off?
Thanks.

listermint

the flat spots on the pipe are for a socket to grip the pipe. For you to take the screw off the end of the pipe. This allows you to remove the pulley wheel.

The bearing would have to be removed with a bearing puller.

Pie Man

listermint wrote: »

the flat spots on the pipe are for a socket to grip the pipe. For you to take the screw off the end of the pipe. This allows you to remove the pulley wheel.

The bearing would have to be removed with a bearing puller.

Thanks, found a video on YouTube showing exactly what to do.

https://youtu.be/1mYDazvQzjE