You may find that additional toolrests can add versatility to your daily turning. They can get expensive if you go out and buy them. I made my own, and it's not that hard.
Some of the toolrests I made are pictured in my AAW gallery
link to the toolrest pics in the photo gallery
The steel used is mild stock steel, I think it might be 1042, aka coldroll. The horizontal piece is 1.0" bar stock. The vertical piece needs to be the same size as your existing tool post, and on the PM3520a, that is 1.0". Do not get stainless. It is very difficult to work (hard to drill, and harder to weld).
Even though this is "mild" steel, it is darned tough. It basically does not bend under normal usage...and I have "tested" them with more than one catch during roughouts. It will get dinged up, but for the usage pattern of roughouts that doesn't matter. And when the U shaped insert is used, there won't be dings.
Tips for construction:
1) I MIG welded these. The steel is thick and that was the easy way to go. If you don't have access to MIG I would suggest you craft the pieces and take them to a local auto shop or welder. Squareness is important when doing the welds. You also want to chamfer the top of the vertical steel post prior to the weld so that there is plenty of surface contact for the welds to hold. This chamfering can be done on a grinding wheel or something similar. With these toolrests I chamfered a 45 degree angle about 1/8" to 3/16" off the edge of the steel rod.
2) I welded the heck out of the pieces. They aren't beautiful, but the extra steel provides a lot of structural integrity. The welds haven't budged.
3) Cutting the holes. Use a drillpress to drill 90 degree holes. Use plenty of lubricating machinist type oil and withdraw the drill bit frequently. Withdrawing the bit helps with extracting the cut material, and also reduces the formation of long steel strands (the strands are also called "swarf").
4) In forging the U shape I made 3 different "U" shaped inserts to fit 3 different toolsizes. They won't be perfect, so you can tune them a bit with a dremel type tool after the forging and welding. The "U" shape insert tops are made from 5/16" or 3/8" mild steel.
5) When you are all done with welding and forging you may want to clean up MIG splatter and machine marks with a dremel tool and a rotating wire brush. The cleanup will smooth out the surfaces and also remove metal pieces which might cut your hands during normal usage. I highly recommend this step. The little leftover MIG spatter marks will definitely cut your skin.
Using the "U" shaped insert
1) In 2 of the posts I drilled holes to accept small U shaped posts for more controlled roughouts. Once you move to a system similar to this it makes you wonder how you ever did hollowing without it. This picture shows a bowl gouge resting in one of the "U" shaped posts:
link to the "U" shaped post picture
2) The post is used to control lateral movement when you are doing roughouts. Just light pressure is needed with one hande near the toolrest holding the tool down, and light pressure from the other hand on the gouge handle guiding the direction of the cut. In this picture there is a single vertical post installed, whereas the "U" shaped insert provides control in both directions:
using a post to control roughout work
Discussion and Critique:
Now, during roughouts the toolrest does the work and mostly I just guide it. No more workouts during roughouts, and they go faster too! The same setup is used for very controlled hollowing. In addition, you can slip a piece of foam insulation on the tool handle to reduce vibration.
One drawback of these toolrests is they are square across the top. They do not provide the ability to do close-in cuts with the tool handle down. It would be better to have some supplementary rests which are not so wide at the very top of the rest (i.e. angled 45 degrees).
Hope this helps. I had fun making the toolposts. The toolrest with the holes and the "U" shaped inserts is the only rest I use for roughouts at this point.
Some of the toolrests I made are pictured in my AAW gallery
link to the toolrest pics in the photo gallery
The steel used is mild stock steel, I think it might be 1042, aka coldroll. The horizontal piece is 1.0" bar stock. The vertical piece needs to be the same size as your existing tool post, and on the PM3520a, that is 1.0". Do not get stainless. It is very difficult to work (hard to drill, and harder to weld).
Even though this is "mild" steel, it is darned tough. It basically does not bend under normal usage...and I have "tested" them with more than one catch during roughouts. It will get dinged up, but for the usage pattern of roughouts that doesn't matter. And when the U shaped insert is used, there won't be dings.
Tips for construction:
1) I MIG welded these. The steel is thick and that was the easy way to go. If you don't have access to MIG I would suggest you craft the pieces and take them to a local auto shop or welder. Squareness is important when doing the welds. You also want to chamfer the top of the vertical steel post prior to the weld so that there is plenty of surface contact for the welds to hold. This chamfering can be done on a grinding wheel or something similar. With these toolrests I chamfered a 45 degree angle about 1/8" to 3/16" off the edge of the steel rod.
2) I welded the heck out of the pieces. They aren't beautiful, but the extra steel provides a lot of structural integrity. The welds haven't budged.
3) Cutting the holes. Use a drillpress to drill 90 degree holes. Use plenty of lubricating machinist type oil and withdraw the drill bit frequently. Withdrawing the bit helps with extracting the cut material, and also reduces the formation of long steel strands (the strands are also called "swarf").
4) In forging the U shape I made 3 different "U" shaped inserts to fit 3 different toolsizes. They won't be perfect, so you can tune them a bit with a dremel type tool after the forging and welding. The "U" shape insert tops are made from 5/16" or 3/8" mild steel.
5) When you are all done with welding and forging you may want to clean up MIG splatter and machine marks with a dremel tool and a rotating wire brush. The cleanup will smooth out the surfaces and also remove metal pieces which might cut your hands during normal usage. I highly recommend this step. The little leftover MIG spatter marks will definitely cut your skin.
Using the "U" shaped insert
1) In 2 of the posts I drilled holes to accept small U shaped posts for more controlled roughouts. Once you move to a system similar to this it makes you wonder how you ever did hollowing without it. This picture shows a bowl gouge resting in one of the "U" shaped posts:
link to the "U" shaped post picture
2) The post is used to control lateral movement when you are doing roughouts. Just light pressure is needed with one hande near the toolrest holding the tool down, and light pressure from the other hand on the gouge handle guiding the direction of the cut. In this picture there is a single vertical post installed, whereas the "U" shaped insert provides control in both directions:
using a post to control roughout work
Discussion and Critique:
Now, during roughouts the toolrest does the work and mostly I just guide it. No more workouts during roughouts, and they go faster too! The same setup is used for very controlled hollowing. In addition, you can slip a piece of foam insulation on the tool handle to reduce vibration.
One drawback of these toolrests is they are square across the top. They do not provide the ability to do close-in cuts with the tool handle down. It would be better to have some supplementary rests which are not so wide at the very top of the rest (i.e. angled 45 degrees).
Hope this helps. I had fun making the toolposts. The toolrest with the holes and the "U" shaped inserts is the only rest I use for roughouts at this point.