Making small circles

[TRITON]

I don't have a bandsaw or a lathe

Certainly an excuse for getting either, or both

You have a drill ?, a saw of some sort ?, screws and glue ?, a chisel or 40 ?, other assorted bits of metal like bolts, nuts and that ilk ?.
DIY Lathe.
Not just ideal for this project, but ideal for other later projects.

 

[Fergie 307]

I was going to say the same as bald kev regarding using the hole saw in a pillar drill to avoid the need for a pilot. But for your bull nose edges? If you have a belt sander you could maybe make a jig that allows the edge to contact the belt at a given distance and angle to chamfer them then round off by hand. If you had a lathe then you could clamp each one between centres and sand the profile on.
If you don't mind the centre hole then the profiling could be done by just threading them into a suitable sized rod with spacers either side to keep them parallel then spin them against a sander.

 

[bobblezard]

Drill some holes say 100mm in some 6mm mdf.

then clamp over your material, rout out with a guide bush -you would need to be careful at breakthrough.

That would be my first approach given the lack of a lathe

 

[Grahammon]

+1 to Recipios reply yesterday at 14:14. One of the wooden toys I used to make, required tyres of a different wood adding, so required accurate inner and outer disks. One way the plans required was a simple jig made out of a 5” square of 3/4 inch ply with a 1/2”x 1”ish routed channel through the middle clamped to your disc sander platform. a 7-8” 1x1/2 stick With a 1/4”small dowel at one end for the pivot. place your over size holesaw disk over the dowel slide the stick into the routed slot and slide until it touches the sanding disk, clamp start the sander and then rotate the wooden disk. Unclamp and reclamp while advancing to the desired size. If you have a router table rinse and repeat with a bull nosed router bit. If anyone’s interested I’ll post the book title, it is fabulous early 1900 - 1930s wooden cars. I’ll have to find it in the workshop otherwise I would have posted here

 

[dephill]

Use your hole saw to cut a hole in some 18mm MDF. Remove the drill from the hole saw, and use the 18mm MDF to guide the hole saw on your desired material. This will cut out circles with no centre hole, quick and simple.

What Richard said, then clean up and round over on router table.
You can use a board with a large ‘v’ notch cut in, clamped to the table to do both. Clean up the edges first but just 3/4depth, then round over the last protruding 1/4 and the other corner. Particularly good if not thick enough for bearing use.
A little breakout doesn’t matter if you’re adding a bullnose.
Can just be seen in this shot, although was using T-slot bit for other job at the time:

 

[BenB]

Cut a neat right angle into some scrap ply, clamp it to your router table. Place your rough disc of wood tight into the elbow. Rotate the disc by hand so the the outer edge of the wood is against the router cutter. Done

 

[johnnyb]

I don't recomend doing the above. just sounds like a finger biter.seriously.

 

[Woodbutcher1960]

I've been making wooden wheels recently to go on cars. I tried lots of different options but the best one was definitely a hole saw in a pillar drill and drilled from both sides. I then mounted the wheel back on the pillar drill with a nut and bolt so that I could use a sanding block to remove the hole saw marks. This also allowed me to round over the edges to make the profile look more like tyres. If you don't want a hole in them, why not cut a hole in a piece of scrap with the hole saw and then remove the pilot bit. You can then use your scrap and a clamp to guide the holesaw in your workpiece. With a simple jig you should still be able to drill from both sides and get the circle spot on. The edges would need some attention, preferably from a router in a table.

 

[dephill]

I don't recomend doing the above. just sounds like a finger biter.seriously.

I don’t think any worse than a router table with bearing guided bit. If the op wants to avoid holes in the middle of his discs it’ll be hard to get a bullnose without some small hazard - a lathe would be safest, or hand tools.
Perhaps double sided to a larger knob of wood for a better grip/more finger clearance.

 

[Bob Chapman]

You don’t have to own a lathe - just find your local wood turning club. Someone there would do the job easily.

 

[dephill]

Cut a neat right angle into some scrap ply, clamp it to your router table. Place your rough disc of wood tight into the elbow. Rotate the disc by hand so the the outer edge of the wood is against the router cutter. Done

That’s what I was trying to say except you need to leave a lip un-routed to ride on the jig otherwise the circle will just keep getting smaller and less circular as the bit cuts deeper.

 

[recipio]

[QUOTE

The plug cutter idea is interesting, although the plug cutters at 60-70mm are very pricey. Would the finish really be noticeably better than a holesaw?
[/QUOTE]

I bought some large plug cutters at a show once - up to 50mm diameter. I soon found out that my puny 350 watt Ryobi drill press would not run them without bogging down. You need a powerful motor on a low speed to power them and yes, the finish is not any better than a holesaw. That V shaped jig looks promising and might just give you the bullnose profile you need.

 

[Craig22]

Trend used to make a router sled/jig called a "pivot frame" which would be useful for this.
Good luck finding one, thoough: I bought the last one machine mart had in the country, 10+ years ago...

It's called the Trend Combination Router Base. Current Trend product. In the range £75 - £80 just doing a google search. I have one I bought maybe 8 years ago to make large holes for mounting loudspeakers.

 

[Craig22]

https://trenddirectuk.com/trend-crb-combination-router-base.html
There are all sorts of ways of using this wonder-gizmo. With the correct radius router cutter you can even curve the edge.

To deal with the small hole in the centre you need for the router base, you could drill a large hole, and then use a plug cutter to make a contrasting plug to fit the hole.

 

[Terrytpot]

I would definitely re-consider the router option, but using double-sided tape to anchor the centre of your small-circle jig, the jig being made something like this:

The jig I use is very much simpler and uses the existing guide rails as part of the mechanism.

I went down this route for a router jig that will make holes or discs of pretty much any size.
https://www.ukworkshop.co.uk/threads/flat-bottomed-25mm-hole.125784/post-1397309

 

[Bigegg]

It's called the Trend Combination Router Base. Current Trend product. In the range £75 - £80 just doing a google search. I have one I bought maybe 8 years ago to make large holes for mounting loudspeakers.

I don't think that's the same thing (again, quick Google search). The CRB doesn't have the wheels?

 

[RobinBHM]

Cut a neat right angle into some scrap ply, clamp it to your router table. Place your rough disc of wood tight into the elbow. Rotate the disc by hand so the the outer edge of the wood is against the router cutter. Done

I don't recomend doing the above. just sounds like a finger biter.seriously

thats a very valid point


A simple piece of wood with a rounded end -screwed on top and protruding over the cutter will make the operation safe

the key is to ensure if your hand slips or the work catches -there is no way of hitting the cutter

 

[peter-harrison]

I'm trying to make a large number of small identical hardwood circles (probably oak) for a child's game. Think small coasters, about 6-7cm diameter, with smooth bullnose edges to use as oversized counters. But I can't work out the best way to do it. I'd like both sides to have no hole in the centre, but I could live with one side having a hole that I could fill.

I've considered a router, but don't think I can easily get a router to turn accurately and repeatedly on that radius. So my next idea is to use a holesaw bit with a removable pilot. That should at least get the basic circle. Then my router table to add the bullnose, overcome the probably poor finish of the holesaw, and get them identical. Should that work, or any better way to do it?

I don't have a bandsaw (one way I've seen for making the rough circles) or a lathe, and I'm not sure I'd be able to get quick repeatable circles with either method in any case given my experience.

I'm hoping someone's done something similar. This place is a great source of advice.

I’ve made lots with a hole saw, and then finished them by chucking them in a drill and sanding on a linisher- if you have a belt sander you could maybe use that held upside down in a vice? This does require at least a half-hole. I think you’d have a lot of trouble trying to clean them up with a router as there’s not a lot to hold on to and you’re working with a lot of adverse grain. Unless you could make some sort of holding jig?
best of luck!

 

[dizjasta]

Another possible method using DIY frame and T4 router. The timber and spelch piece are located on a small pin through base board.

 

[Titan_uk]

Wow people love to get complicated. whats up with 'compassing' your circles onto squares and cutting the corners off on a tangent (and again if necessary) then sand? Clamp some together with a small clamp and sand one side then the other to your lines . All same size and prob faster than a router which you'll have to sand anyway. Unless you're doing lots. I used a Dremel to make some and upending it with a piece of sticky stuff makes a good sander you can adjust the speed on for small circles